@article{wang_du_yang_2023, title={Arterial Signal Coordination Considering the Impacts of Left-Turn Waiting Areas}, volume={149}, ISSN={["2473-2893"]}, DOI={10.1061/JTEPBS.TEENG-7767}, abstractNote={The left-turn waiting area (LTWA) has been commonly used in many signalized intersections to increase the capacity of left-turn movements. However, LTWAs may negatively affect the performance of arterial signal coordination because the lag-lag left-turn phase sequence turns out to be the only feasible left-turn treatment to accommodate the presence of LTWAs. To investigate the effects of LTWAs on arterial signal coordination, this paper proposes an analytical model based on the classic MAXBAND algorithm to quantify the gaps between the actual bandwidth and the maximum possible bandwidth. The model can further identify the applicable signal timing condition of LTWAs in an arterial signal system. A case study of a signalized arterial with LTWAs in Wuhan City was conducted to verify the effectiveness of the proposed method. Results showed that the signal timing parameters obtained from the proposed model resulted in a shorter queue length, a lower delay, and a smaller number of stops when the lag-lag phase sequence was adopted in comparison with the other phase sequences.Practical ApplicationsThe left-turn waiting area (LTWA) has been adopted in many cities to improve operational efficiency for turning traffic, especially for large intersections. However, a lag-lag phase sequence has to be adopted at signalized intersections with LTWA, which would affect the performance of arterial coordination due to the limitations of the phase sequence. The model proposed in this paper could assist field engineers with exploring the appropriate signal timing condition for an arterial coordination system with LTWA intersections, where the lag-lag left-turn phasing scheme could produce wider bandwidth than the other phase sequences. In addition, the rationality of LTWAs in an arterial system could be evaluated further according to the real traffic situation.}, number={10}, journal={JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS}, author={Wang, Daobin and Du, Panpan and Yang, Guangchuan}, year={2023}, month={Oct} }
 @article{li_lian_yang_li_2023, title={Profit-Sharing Contract of the Fresh Agricultural Products Supply Chain under Community Group Purchase Mode Considering Freshness Preservation Efforts}, volume={15}, ISSN={["2071-1050"]}, url={https://www.mdpi.com/2071-1050/15/9/7572}, DOI={10.3390/su15097572}, abstractNote={This article constructed a four-level fresh agricultural product (FAP) supply chain with a two-stage pricing strategy under a “community group purchase (CGP) platform + direct procurement from the FAP supplier” sales model. We investigate the influence of the CGP agency’s participation in the control strategy of FAP freshness preservation efforts on the profits of supply chain stakeholders. This article discusses the effects of the FAP supplier profit-sharing ratio, the CGP agency profit-sharing ratio, and consumers’ sensitivity to FAP freshness on the supply chain stakeholders’ freshness preservation efforts. Moreover, based on the fairness preference theory, this article designed a profit-sharing contract that involves the Nash bargaining game between the FAP supplier and the CGP agency as the supply chain coordination mechanism. Modeling results revealed that: (1) The CGP agency’s freshness preservation efforts increased total supply chain profits. (2) The FAP supplier profit-sharing ratio, CGP agency profit-sharing ratio, and consumers’ sensitivity to FAP freshness have a positive correlation to the profits of the FAP supply chain and promote the coordination of the supply chain. (3) Considering fairness preferences, with the increase in FAP suppliers’ business negotiating ability, their freshness preservation efforts and fairness utility both increased gradually, while the fairness utility of the CGP agency gradually decreased.}, number={9}, journal={SUSTAINABILITY}, author={Li, Min and Lian, Zhen and Yang, Guangchuan and Li, Liaoning}, year={2023}, month={May} }
 @article{yang_cunningham_brown_2023, title={Quadrant Roadway Intersections: Tradeoffs between Control Delay Savings and Extra Travel Time}, volume={9}, ISSN={["2169-4052"]}, DOI={10.1177/03611981231195056}, abstractNote={ A quadrant roadway intersection (QRI) reduces congestion relative to a four-phase intersection. (Note: this study relates to traffic systems where vehicles drive on the right-hand side of the road.) It does this by removing left-turn traffic from the main intersection, resulting in a two-phase signal. Nevertheless, there is a lack of clear understanding of the tradeoffs between savings in control delay versus extra travel time experienced by the rerouted movements. This research compared the operational performance of five QRI designs with the counterpart conventional intersection (CI) under various traffic demand scenarios via TransModeler microsimulation modeling. Three measures-of-effectiveness (MOEs) were employed: time-in-system (TIS), control delay, and intersection capacity utilization. Simulation results show that all QRI designs outperform CI design for all three MOEs under all demand scenarios. QRIs with direct left-turn design have a smaller average TIS than those with loop left-turn design, indicating that savings in control delays did not offset the extra travel times. Under a relatively low demand condition, a single QRI design can generally balance the tradeoffs between control delay and extra travel time. Under a high demand scenario, a dual or full QRI with direct left-turns is preferred, since it reroutes or partially reroutes left- and right-turn traffic to secondary intersections, thus the main intersection has a lower capacity utilization and can accommodate more through-traffic demands than CI, single QRI, and dual or full QRIs with loop left-turns. }, journal={TRANSPORTATION RESEARCH RECORD}, author={Yang, Guangchuan and Cunningham, Christopher M. and Brown, Michael R.}, year={2023}, month={Sep} }
 @article{yang_warchol_cunningham_hummer_2023, title={The potential of signalized offset T-intersections to accommodate new developments}, volume={12}, ISSN={["2046-0449"]}, DOI={10.1016/j.ijtst.2022.01.006}, abstractNote={An offset T-intersection splits a conventional four leg intersection into two three-leg T-intersections to reduce the number of conflicts. While the safety benefits of offset T-intersections have been widely documented, the effects on operations are not well understood. To fix that, this paper employed microsimulation modeling to investigate the differences in operational performance between offset T-intersections and four-leg standard intersections under various traffic demands, intersection spacings, and signal timing schemes for three development types: superstore, hybrid gas station, and residential area. Queue length and delay were employed as measurements of effectiveness. Based on microsimulation modeling, we found that under most of the tested scenarios, offset T-intersections were superior to four-leg intersections in terms of reducing delay for the main street traffic. In addition, we found that the left–right (L-R) offset T-intersection configuration outperformed the right-left (R-L) offset configuration in terms of preventing main-street left turn queue spillback. Based on the simulation results, the paper provided practice-ready guidelines on selecting an optimum intersection configuration for each specific development type given the volume demands and known geometric constraints for a given site.}, number={1}, journal={INTERNATIONAL JOURNAL OF TRANSPORTATION SCIENCE AND TECHNOLOGY}, author={Yang, Guangchuan and Warchol, Shannon and Cunningham, Christopher M. and Hummer, Joseph}, year={2023}, month={Mar}, pages={217–229} }
 @article{chun_rouphail_samandar_list_yang_akcelik_2022, title={Analytical and Microsimulation Model Calibration and Validation: Application to Roundabouts under Sight-Restricted Conditions}, volume={8}, ISSN={["2169-4052"]}, DOI={10.1177/03611981221115071}, abstractNote={ Analytical models and traffic microsimulation are two widely used platforms for evaluating roundabout operations. The application of the correct inputs and proper specification of calibration parameters should precede the actual simulation, to replicate field traffic conditions. In this sense, simultaneous data collection and estimation of the input, calibration, and validation variables, along with knowledge of their definitions, are crucial. Although simultaneity of data gathering is virtually guaranteed with the use of wide-frame videos captured with an unmanned aerial system (UAS), there are cases where sight distance restrictions may obscure observations of the back of queue and arrival patterns. This paper explores the calibration and validation efforts associated with an analytical platform, SIDRA 9, and a microsimulation model, TransModeler 5, conducted under sight-restricted conditions. Video captured from a drone, followed by trajectory extraction using video processing software, was used to analyze operations on two approaches at a single-lane roundabout. In the process, the team employed a specialized demand estimation method, and developed a novel data collection scheme for estimating the critical headway distribution in TransModeler 5. Because of sight distance constraints, the model validation was limited to the use of the observable system travel time and associated travel speed within the field of view. The comparison results, for both platforms, have confirmed the value of model calibration in more accurately describing field performance. The calibrated models performed differently between the two approaches, with the approach having a larger presence of buses and heavy vehicles yielding slightly poorer results. }, journal={TRANSPORTATION RESEARCH RECORD}, author={Chun, Gyounghoon and Rouphail, Nagui and Samandar, M. Shoaib and List, George and Yang, Guangchuan and Akcelik, Rahmi}, year={2022}, month={Aug} }
 @article{yue_yang_zheng_tian_2022, title={Capacity Estimation at All-Way Stop-Controlled Intersections Considering Pedestrian Crossing Effects}, volume={8}, ISSN={["2169-4052"]}, DOI={10.1177/03611981221116368}, abstractNote={ All-way stop-controlled (AWSC) intersections are a typical type of unsignalized intersection that has been commonly used when both intersecting roads have a relatively low vehicular traffic demand. At an AWSC intersection, vehicles proceed through the intersection under a “first come, first served” rule. Since AWSC intersections are often deployed in residential or business areas where pedestrian crossings tend to be inevitable. When a driver who has the right-of-way yields to the crossing pedestrians, the right-of-way at the intersection might be reallocated, which could result in capacity losses to the current approach. On the other hand, the conflicting vehicular traffic movement(s) to the current approach may use this gap and proceed through the intersection ahead of this vehicle. Nevertheless, the effects of pedestrian crossings at AWSCs have not been considered by the existing capacity modeling methods. This research develops a method to evaluate the capacity changes caused by pedestrian crossings at AWSC intersections. Field data collected at two representative sites were collected for model calibration and validation. A sensitivity analysis was conducted to reveal the combined effects of different pedestrian crossing movements and under various pedestrian crossing demands. Results indicated that pedestrian crossing movements could change the capacity at AWSC intersections, but the effects vary according to pedestrian activities and vehicle directions. }, journal={TRANSPORTATION RESEARCH RECORD}, author={Yue, Rui and Yang, Guangchuan and Zheng, Yichen and Tian, Zong}, year={2022}, month={Aug} }
 @article{samandar_chun_yang_chase_rouphail_list_2022, title={Capitalizing on Drone Videos to Calibrate Simulation Models for Signalized Intersections and Roundabouts}, volume={6}, ISSN={["2169-4052"]}, DOI={10.1177/03611981221096120}, abstractNote={ Simulation is an indispensable tool for the assessment of highway-related capital investments and operational changes. Model calibration, a challenging task in any simulation study, is a crucial step. The model’s robustness, accuracy, and quality are directly dependent on it. Many parameters exist, and field observations are often lacking to aid in their correct specification. Recently, videos from drones have created a uniquely powerful way to aid this process. Observations of the inputs (demand), outputs (vehicles processed), processing rates (e.g., saturation flow rates), and performance results (times in system, queue dynamics, and delays) are all available simultaneously. For signalized intersections, only the signal timing events are missing, and those data can be obtained from signal timing logs. This paper illustrates how modeling teams can use drone data to calibrate model parameters pertaining to intersection operation. It shows how saturation flow rates can be adjusted for signalized intersections so that queue dynamics and delays can be matched. For roundabouts, it illustrates how critical gaps and move-up times can be adjusted to match field observations of performance. Three real-world settings with associated drone data are used as case study examples. }, journal={TRANSPORTATION RESEARCH RECORD}, author={Samandar, M. Shoaib and Chun, Gyounghoon and Yang, Guangchuan and Chase, Thomas and Rouphail, Nagui M. and List, George F.}, year={2022}, month={Jun} }
 @article{yue_yang_zheng_yang_tian_2022, title={Effects of Implementing Night Operation Signal Coordination on Arterials}, volume={2022}, ISSN={["2042-3195"]}, DOI={10.1155/2022/1438630}, abstractNote={Traffic signal coordination, which connects a series of signals along an arterial by various coordination methodologies, has been proven as one of the most cost-effective means for alleviating traffic congestion. Various metropolitan planning organizations (MPO) or transportation management centers (TMC) have included signal timing updates in their strategic plans. However, in practice, signal coordination is usually implemented when traffic volume is heavy (i.e., during peak hours). For the rest of the day, the free operation strategy is usually used to reduce the waiting time of uncoordinated phases. However, this free operation strategy may result in the loss of operational efficiency on the major street. Currently, implementing signal coordination during off-peak hours is rare in the U.S. since there is lack of an efficient method that considers traffic operations for both the major and the minor streets. Therefore, this research provides a novel method that balances the control delays between the major street and the minor street. The procedure is to optimize the splits of the major street while also using the reservice strategy in the signal controller for the minor street. Microsimulation modeling was employed to assess the performance of traffic signal coordination during off-peak periods. Results show that, under reasonable splits, the coordination effect on the major street can be achieved and protected with an acceptable delay to minor street traffic. The strategy can be immediately implemented to reduce travel time for major street traffic.}, journal={JOURNAL OF ADVANCED TRANSPORTATION}, author={Yue, Rui and Yang, Guangchuan and Zheng, Yichen and Yang, Yang and Tian, Zong}, year={2022}, month={Aug} }
 @article{li_he_yang_lian_2022, title={Profit-Sharing Contracts for Fresh Agricultural Products Supply Chain Considering Spatio-Temporal Costs}, volume={14}, ISSN={["2071-1050"]}, DOI={10.3390/su14042315}, abstractNote={This paper investigated the effects of the informational asymmetry phenomenon that occurs in the direct sale of fresh agricultural products (FAP) in an e-commerce environment. A three-level FAP supply chain was proposed, which was composed of a FAP supplier, a logistics service provider, and a large e-commerce platform. Considering the perishable nature of FAP, this paper analyzed the effects of logistics spatio-temporal costs and the freshness of FAP on the profit of each stakeholder in the supply chain. Three scenarios were considered: (1) complete information, (2) partial information, and (3) considering logistics spatio-temporal cost. Analytical models were developed based on the principal-agent theory and the supply chain coordination contract theory to depict the effects of a profit-sharing contract on the operations of the FAP supply chain. Modeling results indicated that under a complete information condition, an increase in the loss rate of FAP correlated to a decrease in the profit of the FAP supply chain. Under a partial information condition, considering the loss rate of FAP and the potential compensation costs to suppliers, when the loss rate of FAP was fixed, the profit of each stakeholder in the FAP supply chain displayed a decreasing trend in relation to compensation ratio. In comparison, when the compensation ratio was fixed, the total profit decreased as the freshness of the FAP degraded. To improve customer satisfaction, this paper recommends adding a front warehouse to improve the freshness of FAP. Although this option increases the logistics costs, it has the potential of increasing the overall profit of the FAP supply chain. Findings from this research have the potential to help the e-commerce platform with coordinating the various stakeholders on the supply chain to determine the optimal quality and quantity of FAPs, eventually improving the operational efficiency of the FAP direct sales supply chain by reducing the logistics costs of FAP.}, number={4}, journal={SUSTAINABILITY}, author={Li, Min and He, Lina and Yang, Guangchuan and Lian, Zhen}, year={2022}, month={Feb} }
 @article{wang_yang_tian_wei_2022, title={Traffic Queue Length Estimation at Permissive Left-Turn Signalized Intersections with Probabilistic Priority}, volume={148}, ISSN={["2473-2893"]}, DOI={10.1061/JTEPBS.0000764}, abstractNote={Probabilistic yielding behaviors are often observed at permissive left-turn signalized intersections in some countries, which tend to affect the operational performance of intersections such as queue length of left-turn traffic. Based on queuing theory, this research developed an analytical queue length estimation model that took into account the probabilistic priority phenomenon at permitted left-turn signals. The service time distributions for both queued and nonqueued left-turn vehicles were derived, and the M/G2/1 queuing model was applied to determine the queue length of left-turn traffic. To validate the developed queue length model, stochastic simulations with different combinations of left-turn yielding rates, left-turn traffic saturation ratios, and through traffic flow rates were performed. It was found that the left-turn traffic saturation ratio is the most critical factor for the estimation of left-turn traffic queue length. In addition, for permitted intersections with a single through lane and a single left-turn lane, when the opposite through traffic flow rate is greater than 0.3 veh/s, the impact of left-turn yielding rate on left-turn queue length tends to be more significant.}, number={12}, journal={JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS}, author={Wang, Daobin and Yang, Guangchuan and Tian, Zong and Wei, Dali}, year={2022}, month={Dec} }
 @article{yang_coble_vaughan_peele_morsali_list_findley_2022, title={Waiting Time Estimation at Ferry Terminals Based on License Plate Recognition}, volume={148}, ISSN={["2473-2893"]}, url={https://doi.org/10.1061/JTEPBS.0000722}, DOI={10.1061/JTEPBS.0000722}, abstractNote={The ferry transit system provides a critical transportation link in coastal areas for both residents and tourists. Like signals in a road network, queuing and waiting are unavoidable at ferry terminals. However, a reliable technology does not exist to measure and communicate waiting times. This research tested the feasibility of applying license plate recognition (LPR) technology to track vehicles and estimate waiting times at ferry terminals. The LPR camera sampling rate, capture rate, read rate, and match rate were adopted as measurements of effectiveness. Based on field data collected over a week at one of the busiest ferry terminals in North Carolina, this research revealed that the tested LPR camera had a sampling rate of 84.2%; the average capture rate and read rate were 84.3% and 87%, respectively. The match rate was found to be 79.4%, which is significantly higher than other commonly used data collection technologies such as Bluetooth devices. For the waiting time distribution, this research found that travelers tended to experience long waiting times during midweek days, particularly during the midday period. Additionally, the demand was found to be the primary factor for wait times during the midday peak period, and travelers’ arrival time in terms of proximity to the scheduled ferry departure time was recognized as the key factor for waiting time during early morning and later evening nonpeak periods.}, number={9}, journal={JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS}, author={Yang, Guangchuan and Coble, Daniel and Vaughan, Chris and Peele, Catherine and Morsali, Atefeh and List, George F. and Findley, Daniel J.}, year={2022}, month={Sep} }
 @article{yue_yang_zheng_tian_2021, title={Effects of Pedestrian Crossing on Minor Road Capacity at Two-Way Stop-Controlled Intersections}, volume={4}, ISSN={["2169-4052"]}, DOI={10.1177/03611981211002836}, abstractNote={ Two-way stop-controlled (TWSC) intersections have been used extensively in the United States and other parts of the world when traffic signal control is not warranted. However, it was found that when a major road vehicle yields to crossing pedestrians, minor road traffic could use this extra gap, which tends to improve the capacity of some minor vehicle movements. The current capacity modeling methods did not take into account the effects of the pedestrian crossing on minor road capacity. This paper proposes an analytical model to quantify the increased capacity of minor street movements contributed by minor street pedestrian crossings and validates the model using both field data collected at a three-leg TWSC intersection and through the stochastic simulation method. A sensitivity analysis was performed to reveal the impacts of various factors on minor road capacity. In general, it was found that minor road left-turn capacity at the study intersection was positively correlated to pedestrian crossing volume, yielding rate, and pedestrian crossing time. Besides, modeling results showed that under relatively heavier conflict traffic volume conditions, the effect of the pedestrian crossing on increased capacity on the minor road was more significant. }, journal={TRANSPORTATION RESEARCH RECORD}, author={Yue, Rui and Yang, Guangchuan and Zheng, Yichen and Tian, Zong}, year={2021}, month={Apr} }
 @article{jiang_nian_guo_ahmed_yang_ma_2021, title={Evaluating connected vehicle-based weather responsive management strategies using weather-sensitive microscopic simulation}, volume={10}, ISSN={["1547-2442"]}, DOI={10.1080/15472450.2021.1990052}, abstractNote={Abstract The purpose of this study is to perform analysis, modeling, and simulation (AMS) to investigate the effectiveness of connected vehicle (CV)-based Weather Responsive Management Strategies (WRMS) to address safety concerns on freeway corridors under adverse weather conditions. This study investigates three CV-based WRMS applications: Forward Collision Warning (FCW), Early Lane Change (ELC) advisory, and Variable Speed Limit (VSL), designs operational alternatives for WRMS using CV data, and develops an AMS tool using a weather-sensitive microscopic traffic simulator to understand the effectiveness of the three WRMS under different scenarios. Various CV market penetration rates (MPR), weather conditions, and WRMS algorithm settings are tested in this study. The case study is based on a real-world freeway corridor, a segment of the I–80 Connected Vehicle Testbed in Wyoming. The simulation results show the effectiveness of selected WRMS applications and provide operational insights that state and local transportation agencies may use in future strategic planning and operations of their weather-responsive programs.}, journal={JOURNAL OF INTELLIGENT TRANSPORTATION SYSTEMS}, author={Jiang, Qinhua and Nian, Dong and Guo, Yi and Ahmed, Mohamed and Yang, Guangchuan and Ma, Jiaqi}, year={2021}, month={Oct} }
 @article{yue_yang_lin_wang_tian_2021, title={Traffic Signal Retiming to Improve Corridor Performance}, volume={147}, ISSN={["2473-2893"]}, DOI={10.1061/jtepbs.0000482}, abstractNote={AbstractTraffic signal retiming involves periodically updating existing signal coordination plans of signalized corridors. Nevertheless, there are still several limitations with the current signal ...}, number={1}, journal={JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS}, author={Yue, Rui and Yang, Guangchuan and Lin, Dongmei and Wang, Aobo and Tian, Zong}, year={2021}, month={Jan} }
 @article{an integrated microsimulation modeling approach for safety performance assessment of the wyoming connected vehicle pilot deployment program_2020, journal={Accident Analysis and Prevention}, year={2020}, month={Aug} }
 @article{analysis, modeling and simulation framework for performance evaluation of the wyoming connected vehicle pilot deployment program_2020, journal={Advances in Transportation Studies}, year={2020}, month={Jun} }
 @article{assessment of drivers’ perceptions of connected vehicle human-machine interface for driving under adverse weather conditions: preliminary findings from wyoming_2020, journal={Frontiers in Psychology}, year={2020}, month={Aug} }
 @article{wang_yang_tian_liu_wei_2020, title={Capacity Modeling of Permitted Left-Turn Signalized Intersections with Probabilistic Priority}, volume={2674}, ISSN={["2169-4052"]}, DOI={10.1177/0361198120934802}, abstractNote={ Probabilistic yielding behavior is commonly observed at permitted left-turn signalized intersections in China. Nevertheless, its impact on traffic capacity has not been explored in existing research. The uniqueness of this traffic operation is that neither left-turn traffic nor through traffic holds an absolute priority. Based on queuing theory, this research developed an analytical capacity model that took into account the probabilistic priority phenomenon at permitted left-turn signals. To validate the developed capacity model, stochastic simulations with different combinations of left-turn traffic yielding rates and through-traffic flow rates were performed. It was found that modeling results from the analytical model precisely matched the stochastic simulation results. In comparison with traditional capacity estimation models that assumed through traffic holds an absolute priority, this research revealed that when through-traffic flow rate is around 1000 vehicles per hour (vph), the capacity of left-turn traffic increased from 233 vph to 536 vph when left-turn traffic yielding rates decrease from 1 to 0.2; whereas when left-turn traffic yielding rates decreased from 0.2 to 0, left-turn capacity increased sharply to 1200 vehicles per hour (vph). In this regard, it is critical to take into account the probabilistic left-turn yield behavior when developing permitted left-turn signal warrants. }, number={10}, journal={TRANSPORTATION RESEARCH RECORD}, author={Wang, Daobin and Yang, Guangchuan and Tian, Zong and Liu, Wei and Wei, Dali}, year={2020}, month={Oct}, pages={310–323} }
 @article{connected vehicle real-time traveler information messages for freeway speed harmonization under adverse weather conditions_2020, journal={Accident Analysis and Prevention}, year={2020}, month={Aug} }
 @article{connected vehicle training framework and lessons learned to improve safety of highway patrol troopers_2020, journal={Transportation Research Record}, year={2020}, month={Oct} }
 @article{shen_yang_2020, title={Crash Risk Assessment for Heterogeneity Traffic and Different Vehicle-Following Patterns Using Microscopic Traffic Flow Data}, url={https://www.mdpi.com/2071-1050/12/23/9888}, DOI={10.3390/su12239888}, abstractNote={This paper investigates the impacts of heavy vehicles (HV) on speed variation and assesses the rear-end crash risk for four vehicle-following patterns in a heterogeneous traffic flow condition using three surrogate safety measures: speed variation, time-to-collision (TTC), and deceleration rate to avoid a crash (DRAC). A video-based data collection approach was employed to collect the speed of each individual vehicle and vehicle-following headway; a total of 3859 vehicle-following pairs were identified. Binary logistic regression modeling was employed to assess the impacts of HV percentage on crash risk. TTCs and DRACs were calculated based on the collected traffic flow data. Analytical models were developed to estimate the minimum safe vehicle-following headways for the four vehicle-following patterns. Field data revealed that the variation of speed first increased with HV percentage and reached the maximum when HV percentage was at around 0.35; then, it displayed a decreasing trend with HV percentage. Binary logistic regression modeling results suggest that a high risk of rear-end collision is expected when HV percentage is between 0.19 and 0.5; while, when HV percentage is either below 0.19 or exceed 0.5, a low risk of rear-end collision is anticipated. Analytical modeling results show that the passenger car (PC)-HV vehicle-following pattern requires the largest minimum safe space headway, followed by HV-HV, PC-PC, and HV-PC vehicle-following patterns. Findings from this research present insights to transportation engineers regarding the development of crash mitigation strategies and have the potential to advance the design of real-time in-vehicle forward collision warnings to minimize the risk of rear-end crash.}, journal={Sustainability}, author={Shen, Jiajun and Yang, Guangchuan}, year={2020}, month={Nov} }
 @article{distraction of connected vehicle human-machine interface for truck drivers_2020, journal={Transportation Research Record}, year={2020}, month={Jul} }
 @article{modeling the modal shift effects of converting a general traffic lane to a dedicated bus lane_2020, journal={Promet – Traffic and Transportation}, year={2020}, month={Sep} }
 @article{uncovering impact factors of carbon emissions from transportation sector: evidence from china’s yangtze river delta area_2020, journal={Mitigation and Adaptation Strategies for Global Change}, year={2020}, month={Oct} }
 @article{ahmed_gaweesh_yang_2019, title={A Preliminary Investigation into the Impact of Connected Vehicle Human-Machine Interface on Driving Behavior}, volume={51}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85061149386&partnerID=MN8TOARS}, DOI={10.1016/j.ifacol.2019.01.051}, abstractNote={This paper developed a driving simulator testbed, which includes three simulation scenarios that can represent different real-world driving conditions, to investigate the impact of Connected Vehicle (CV) Human-Machine Interface (HMI) on driving behavior. A total number of 23 professional drivers were invited to participate in the driving simulator test; a comprehensive questionnaire was employed to collect the participant’s feedback of CV HMI. It was found that 96 percent of the participants stated that CV HMI provided them with improved road condition information and increased their safety while driving; 65 percent of the participants stated the CV applications and the display unit did not introduce significant distraction from the main driving task.}, number={34}, journal={IFAC-PapersOnLine}, author={Ahmed, M.M. and Gaweesh, S. and Yang, G.}, year={2019}, pages={227–229} }
 @article{an integrated empirical analysis of the effect of variable message sign on driver route choice behavior_2019, journal={Journal of Transportation Engineering, Part A: System}, year={2019}, month={Nov} }
 @article{an exploratory investigation of the impact of ramp metering on driver acceleration behavior_2019, url={http://dx.doi.org/10.1016/j.iatssr.2019.03.002}, DOI={10.1016/j.iatssr.2019.03.002}, abstractNote={Ramp metering has been proven as an effective freeway management strategy; however, the impact of ramp metering on drivers' acceleration behavior has not been fully investigated. A better understanding of acceleration behavior changes with ramp metering is critical to the adequate design of ramp metering facilities. In this study, drivers' speed and acceleration data were collected at two representative metered ramps in Los Angeles, California. The speed and acceleration profiles under meter-on and meter-off scenarios were compared. Statistical results demonstrated that ramp metering affects drivers' acceleration behavior at ramp acceleration lane. It was found that at the metered ramp with short existing acceleration length, the average acceleration rate from ramp meter stop bar to 500 ft downstream under meter-on scenario (4.72 ft./s2) is approximately 40% higher than when meter-off (3.18 ft./s2). The design of acceleration lane length for metered on-ramps should therefore take into account the potential impacts of ramp metering on driver acceleration behavior.}, journal={IATSS Research}, year={2019}, month={Mar} }
 @article{capacity of urban arterial weaving sections under lane signal control strategy_2019, url={http://dx.doi.org/10.1177/0361198119844752}, DOI={10.1177/0361198119844752}, abstractNote={ An urban arterial weaving section has been considered a bottleneck in urban roadway systems, which is one of the key contributing factors to the occurrence of the capacity-drop phenomenon. This paper proposes a novel lane signal control method to regulate the weaving traffic flow at urban arterial weaving sections. With consideration of the operational characteristics of the weaving section and the imbalance of traffic at each entrance lane, a reduction coefficient of the weaving traffic was adopted. A capacity calculation model for weaving traffic under lane signal control was developed. The optimization model was established to derive the optimal lane signal control scheme. The objective function was to maximize the weaving section’s capacity, and the constraints were the safe time headway between two adjacent phases. The proposed capacity estimation model was validated using field data collected at a representative urban arterial weaving section in Chongqing City, China; it was found that the mean absolute percent error was 4.7%. Modeling results demonstrate that the actual capacity of the weaving section significantly increased after adopting the lane signal control strategy. During the morning peak period, the actual capacity was 3,265 pcph (passenger cars per hour), which improves by 28.14% under the optimal scheme of two-phase lane signal control. The weaving capacity improvement for the three-phase lane single control is found to be 3,458 pcph, which improves by 35.71% under the three-phase control strategy. This paper used capacity reduction as index to test the robust of entrance lane, facing the increasing demand for traffic. }, journal={Transportation Research Record: Journal of the Transportation Research Board}, year={2019}, month={Jun} }
 @article{determination of bus crowding coefficient based on passenger flow forecasting_2019, url={http://dx.doi.org/10.1155/2019/2751916}, DOI={10.1155/2019/2751916}, abstractNote={To improve bus passengers’ degree of comfort, it is necessary to determine the real-time crowd coefficient in the bus. With this concern, this paper employed the RBF Neural Networks approach to predict the number of passengers in the bus based on historical data. To minimize the impact of the randomness of passenger flow on the determination of bus crowd coefficient, a cloud model-based bus crowd coefficient identification method was proposed. This paper first selected the performance measurements for determining bus crowd coefficient and calculated the digital characteristics of the cloud model based on the boundary values of the selected performance measures under six Levels-of-Service (LOSs). Then the subclouds obtained under the six LOSs were synthesized into a standard cloud. According to the predicted number of passengers in the bus, the passenger density and loading frequency were calculated, which were imported into the cloud generator to set up the bus crowd coefficient identification model. By calculating the crowd degrees of identification cloud and template cloud at each site, this paper determined the crowed coefficient of each bus station. Finally, this paper took the bus line No. 10 in Dalian city as case study to verify the proposed model. It was found that the crowd coefficients of the selected route ranged from 60.265 to 109.825, and the corresponding LOSs ranged between C and F. The method of discriminating bus crowding coefficient can not only effectively determine the congestion coefficient, but also effectively avoid the fuzziness and randomness of the crowding coefficient judgment in the bus, which has strong theoretical and practical significance.}, journal={Journal of Advanced Transportation}, year={2019}, month={Apr} }
 @book{ahmed_yang_gaweesh_2019, title={Development and Assessment of a Connected Vehicle Training Program for Truck Drivers}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85061928436&partnerID=MN8TOARS}, DOI={10.1177/0361198119827904}, abstractNote={ In Wyoming, because of the high likelihood of dangerous winter driving conditions, truck-related crashes on the freeway have resulted in remarkable fatalities, extended closures, and significant economic losses. The emerging connected vehicle (CV) technology has the potential to communicate road and traveler information to commercial truck drivers, which would eventually promote traffic safety. Nevertheless, currently there is a lack of a systems training program to deliver the CV technology to truck drivers. This paper developed a CV training program which contained an e-learning conceptual education module and a hands-on driving simulator training module. The e-learning module presented the concept of various CV warnings and notifications, including forward collision warning (FCW), distress notification (DN), and traveler information messages (TIMs). The hands-on driving simulator training module provided participants with a simulated environment where they could practice the CV warnings that they had met during the e-learning. Five simulation scenarios were provided to the participants, including two single-alert scenarios and three multiple-alert scenarios. A quiz section in the e-learning module and a comprehensive post-training questionnaire survey within the hands-on module were employed to evaluate the effectiveness of the developed CV training program. Based on the feedback of 18 professional snowplow truck drivers from the Wyoming Department of Transportation, it was found that the proposed training program provided truck drivers with up-to-date knowledge and experience on CV technology. }, journal={Transportation Research Record}, author={Ahmed, M.M. and Yang, G. and Gaweesh, S.}, year={2019} }
 @article{discussion of “queue storage design for metered on-ramps” by zhongren wang_2019, url={http://dx.doi.org/10.1016/j.ijtst.2019.02.004}, DOI={10.1016/j.ijtst.2019.02.004}, abstractNote={This article presented a discussion on a research paper entitled “Queue Storage Design for Metered On-Ramps”, published by the International Journal of Transportation Science and Technology on March 2013 (Volume 2, Issue 1, Pages 47–63). This discussion first summarized the contributions of the paper under discussion, and emphasized a critical insight presented by the paper under discussion that designing queue storage length as a percentage of peak hour on-ramp demand. Then, this article discussed the potential factors that may affect queue length estimation results, including different traffic flow arrival patterns between arterial-to-freeway ramps and freeway-to-freeway connectors, queue length as a function of demand-to-capacity ratio instead of on-ramp traffic volume, and errors caused by the stochastic nature of traffic flow when using field measured queues. Lastly, this article outlined methods to solve these limitations, and presented preliminary insights into the development of metered on-ramp queue storage length design guidelines considering the impacts of ramp geometric features and signal timing schemes of the upstream intersection.}, journal={International Journal of Transportation Science and Technology}, year={2019}, month={Mar} }
 @article{feasibility of using a single traffic signal controller to accommodate adjacent intersections_2019, url={http://dx.doi.org/10.1016/j.ijtst.2019.09.002}, DOI={10.1016/j.ijtst.2019.09.002}, abstractNote={Abstract The operation cost of signalized intersections is usually higher than unsignalized intersections, not only because of the expenses on hardware devices but also due to the device maintenance as well as software upgrading. Moreover, at a signalized corridor, the coordination between signals is also considered to be necessary, which requires additional labor and maintenance costs. With these considerations, this paper aimed to investigate the feasibility of using a single signal controller to control two or multiple adjacent intersections. This study developed a procedure to decide when to use one-controller strategy and evaluated the operation of two real-world cases in Reno, Nevada, where the previous two-controller strategy has just replaced by a one-controller strategy. Based on microsimulation study, it was concluded that the Level-of-Service (LOS), delay, and the average number of stops under one-controller strategy maintained a similar condition in comparison with the previous two-controller strategy, indicating that the proposed one-controller strategy would be a feasible alternative to reduce the operation costs of adjacent intersections. It is expected that reducing the number of signal controllers will not only reduce the infrastructure cost, but also lead to notable operation benefits, such as it facilitates the development of signal coordination plans, and the implementation of future adaptive signal control in a connected vehicle environment, since it reduced the number of communication nodes within the arterial system.}, journal={International Journal of Transportation Science and Technology}, year={2019}, month={Sep} }
 @article{geometric design of metered on-ramps: state-of-the-practice and remaining challenges_2019, url={http://dx.doi.org/10.1080/19427867.2019.1677067}, DOI={10.1080/19427867.2019.1677067}, abstractNote={ABSTRACT Successful operation of ramp-metering needs to provide both an adequate queue storage space and a sufficient acceleration length at a metered on-ramp. This paper reviewed the existing methodologies and practices pertaining to queue storage and acceleration length design at metered on-ramps, and identified challenges that need to be solved during the metered on-ramp geometric design process. It was summarized that the development of metered on-ramp queue storage design guideline needs to consider the impact of on-ramp traffic flow arrival pattern on the actual queue storage needs at various metered on-ramp types. Meanwhile, considering the potential impact of ramp-metering on drivers’ acceleration behavior, it is necessary to develop dedicated acceleration lane length design standards for metered on-ramps based on field collected acceleration performance data. In addition, it is desirable to establish clear ramp geometric warrants to enhance the existing ramp-metering warrants presented in the MUTCD and local ramp meter design guidelines.}, journal={Transportation Letters}, year={2019}, month={Oct} }
 @article{yang_tian_wang_xu_yue_2019, title={Impact of On-Ramp Traffic Flow Arrival Profile on Queue Length at Metered On-Ramps}, volume={145}, DOI={10.1061/jtepbs.0000211}, abstractNote={AbstractAt a metered on-ramp, a vehicle queue will be formed in front of the ramp meter when on-ramp demand exceeds the ramp-metering capacity. It is therefore important to provide adequate queue s...}, number={2}, journal={Journal of Transportation Engineering, Part A: Systems}, publisher={American Society of Civil Engineers (ASCE)}, author={Yang, Guangchuan and Tian, Zong and Wang, Zhongren and Xu, Hao and Yue, Rui}, year={2019}, month={Feb}, pages={04018087} }
 @article{impact of variable speed limit in a connected vehicle environment on truck driver behavior under adverse weather conditions: driving simulator study_2019, url={http://dx.doi.org/10.1177/0361198119842111}, DOI={10.1177/0361198119842111}, abstractNote={ In 2015, the U.S. Department of Transportation (U.S. DOT) selected Wyoming as one of three sites to develop, test, and deploy a suite of connected vehicle (CV) applications on a 402-mi Interstate 80 corridor. One of the Wyoming’s key CV applications is the variable speed limit (VSL) warning, which aimed to provide commercial truck drivers with real-time regulatory and advisory speed limits to help in better managing speeds under adverse weather conditions, and reducing potential speed variances that may cause traffic collisions. This paper developed a driving simulator testbed to assess the impact of the Wyoming’s CV-based VSL (CV-VSL) application on truck drivers’ behavior under adverse weather conditions. A total of 18 professional truck drivers were recruited to participate in the driving simulator experiment. Participants’ instantaneous speeds at various locations were collected to reveal the impact of the CV-VSL warnings on their driving behavior. Simulation results showed that when the advisory speed limits were lower than 55 mph, participants generally followed the VSLs displayed on the CV human–machine interface (HMI). In addition, traffic flows utilizing CV-VSL technology tend to exhibit lower average speeds and speed variances compared with baseline scenarios. These effects of CV-VSL warnings can bring potential safety benefits, as reduction in average speeds and speed variances are effective surrogate measures of safety, that is, lower risk of crashes, under adverse weather conditions. }, journal={Transportation Research Record}, year={2019}, month={Apr} }
 @article{microsimulation analysis of traffic operations at two diamond interchange types_2019, url={http://dx.doi.org/10.1155/2019/6863480}, DOI={10.1155/2019/6863480}, abstractNote={The operational performance of standard Single Point Urban Interchange (SPUI) and Tight Diamond Interchange (TDI) has already been widely studied. In general, SPUI is more efficient than a TDI in terms of increased capacity and decreased traffic delays even though building a SPUI generally incurs a higher cost. However, due to right-of-way constraints, a standard SPUI may not be implementable at locations with restricted land use; thus, the variations of SPUI are usually considered. Currently, there is no established methodology or guideline available on the performance evaluation of variations of SPUI. This paper aims to investigate the operational efficiency of SPUI with frontage roads (SPUI-F, a variation of SPUI). Based on a field case, the performance of SPUI-F was investigated using microsimulation. An analytical model for capacity estimation, which considered early return and discharge flow rate, was also established and validated based on microsimulation. Multiple traffic scenarios were analyzed and their performance measures were compared against the equivalent TDI design. Simulation results revealed that TDI outperformed SPUI-F in terms of average delay, speed, and queue length, and the proposed analytical model can be used for reliable capacity and delay estimation. The findings from this study can aid the decision-makers choosing an appropriate interchange type for achieving the best benefit-cost ratio.}, journal={Journal of Advanced Transportation}, year={2019}, month={Mar} }
 @article{performance evaluation framework of wyoming connected vehicle pilot deployment program: summary of phase 2 pre-deployment efforts and lessons learned_2019, url={http://dx.doi.org/10.1108/jicv-03-2019-0006}, DOI={10.1108/jicv-03-2019-0006}, abstractNote={
Purpose
This paper aims to present a summary of the performance measurement and evaluation plan of the Wyoming connected vehicle (CV) Pilot Deployment Program (WYDOT Pilot).
}, journal={Journal of Intelligent and Connected Vehicles}, year={2019}, month={Aug} }
 @article{virtual controller interface device for hardware-in-the-loop simulation of traffic signals_2019, journal={IEEE Intelligent Transportation Systems Magazine}, year={2019}, month={Apr} }
 @article{wang_tian_yang_gholami_2018, title={         Comparison of performance between Virtual Controller Interface Device and Controller Interface Device      }, volume={12}, DOI={10.1049/iet-its.2017.0050}, abstractNote={A Controller Interface Device (CID) is a hardware that connects a signal controller to simulation software. Running traffic simulation with an actual controller is called hardware-in-the-loop simulation (HILS) and is an important tool for simulating the operations of traffic signals. In practice, it has been found that the existing traditional CIDs have some limitations, particularly when simulating multiple signals. In this regard, a Virtual CID (VCID) is proposed in this study. VCID can connect traffic signal controllers to a micro-simulation software through the National Transportation Communications for ITS Protocol (NTCIP). A case study is conducted that uses the same traffic networks to compare the performance of VCID to CID. Queue length, travel time and simulation stability are considered in the evaluation. Results show that VCID could provide accurate and reliable simulation results. In comparison to traditional CIDs, VCID has more advantages as it does not depend on any hardware device and is easy to operate. In addition, since the communications are transformed through Ethernet, thus providing a convenient learning and testing environment for those who do not own a physical signal control laboratory. Therefore, VCID will have a broader prospect for development than CID.}, number={1}, journal={IET Intelligent Transport Systems}, publisher={Institution of Engineering and Technology (IET)}, author={Wang, Daobin and Tian, Zong and Yang, Guangchuan and Gholami, Ali}, year={2018}, month={Feb}, pages={22–30} }
 @article{evaluation of virtual controller interface device and software-in-the-loop simulation_2018, url={https://doi.org/10.1680/jtran.17.00149}, DOI={10.1680/jtran.17.00149}, abstractNote={ In current practice, hardware-in-the-loop simulation and software-in-the-loop simulation are two typical methods for traffic signal control research. The former uses a controller interface device (CID) to connect an actual traffic signal controller to micro-simulation software when conducting a simulation, whereas the latter uses software packages to take the roles of actual signal controllers. Using an actual signal controller can help to generate more reliable simulation results; however, the operational costs of CIDs limit the applicability of hardware-in-the-loop simulations. In this paper, a virtual controller interface device (VCID) is proposed to connect the actual signal controllers to simulation software. The proposed device communicates with the actual signal controller through the US national transportation communications for intelligent transportation systems protocol (NTCIP), which provides great operation flexibility, such as remote control, and reduces the operating costs compared with previous hardware-in-the-loop simulations. The simulation performance of the VCID is compared with software-in-the-loop simulations through a case study in this paper. It is found that the proposed device is able to provide accurate and reliable traffic simulation results: the relative difference with software-in-the-loop simulations is only 1·8%, but it requires significantly less effort and has a lower cost. }, journal={Proceedings of the Institution of Civil Engineers - Transport}, year={2018}, month={Oct} }
 @article{yang_wang_xu_tian_2018, title={Feasibility of Using a Constant Acceleration Rate for Freeway Entrance Ramp Acceleration Lane Length Design}, volume={144}, DOI={10.1061/jtepbs.0000122}, abstractNote={AbstractWhen estimating the required acceleration length of vehicles accelerating from a stopped position, a constant acceleration rate is sometimes assumed for the sake of simplicity. Nevertheless...}, number={3}, journal={Journal of Transportation Engineering, Part A: Systems}, publisher={American Society of Civil Engineers (ASCE)}, author={Yang, Guangchuan and Wang, Zhongren and Xu, Hao and Tian, Zong}, year={2018}, month={Mar}, pages={06017001} }
 @article{yang_yue_tian_xu_2018, title={Modeling the Impacts of Traffic Flow Arrival Profiles on Ramp Metering Queues}, volume={6}, DOI={10.1177/0361198118782253}, abstractNote={ An adequate queue storage length is critical for a metered on-ramp to prevent ramp queue spillback to the upstream signalized intersection. Previous research on queue length estimation or queue storage length design at metered ramps has not taken into account the potential impact of various on-ramp traffic flow arrival profiles on ramp queue lengths. This paper depicts the traffic flow arrival profiles and queue generation processes at three different metered ramp categories. Based on a large number of microscopic simulation runs, it is found that, under a given demand-to-capacity scenario, the queue at a metered ramp with two on-ramp feeding movements is more likely to be cleared in a cycle than at a metered ramp with three on-ramp feeding movements. Also, the platoon dispersion effect significantly reduces the ramp queue length, and hence the queue storage needs at a metered ramp. In addition, this paper reveals that ramp queue length tends to increase linearly with upstream signal cycle length. The design of queue storage length for a metered on-ramp hence needs to fully consider the various ramp configurations and upstream signal timing settings. }, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={SAGE Publications}, author={Yang, Guangchuan and Yue, Rui and Tian, Zong and Xu, Hao}, year={2018}, month={Jun}, pages={036119811878225} }
 @article{yang_tian_wang_xu_2018, title={Queue length estimation for a metered on-ramp using mesoscopic simulation}, volume={5}, DOI={10.1080/19427867.2018.1477491}, abstractNote={Abstract This paper proposed an analytical method for queue length modeling at a metered on-ramp, and developed a mesoscopic simulation model for queue length estimation under various demand-to-capacity scenarios. Queue length data were collected at four representative ramp metering locations for model validation; results showed that the queue length modeling method could properly capture the realistic queue profile, and the estimated queue lengths were close to the field observations. It was found that for under-saturated scenarios, queue length showed an exponential increasing trend with demand-to-capacity ratio; while for over-saturated scenarios, the queue length tended to increase linearly with demand-to-capacity ratio. Simulation results indicated that for under-saturated conditions, the required queue storage length was approximately 5.7 percent of on-ramp demand when demand was less than 500 vphpl, or 3.9 percent when demand was between 500 and 900 vphpl.}, journal={Transportation Letters}, publisher={Informa UK Limited}, author={Yang, Guangchuan and Tian, Zong and Wang, Daobin and Xu, Hao}, year={2018}, month={May}, pages={1–10} }
 @article{yang_tian_xu_wang_wang_2017, title={Impacts of traffic flow arrival pattern on the necessary queue storage space at metered on-ramps}, volume={14}, DOI={10.1080/23249935.2017.1387875}, abstractNote={ABSTRACT This paper compares queue lengths at the two different on-ramp configurations: arterial-to-freeway ramp and freeway-to-freeway connector. Mesoscopic queue length simulation models are developed based on the input-output method. The input-output method aims to model the traffic flow arrival profile; then, the mesoscopic simulation model generates random traffic volume to simulate the stochasticity of traffic flow. The simulation models are validated using field-collected data. Simulation results indicated that the traffic flow arrival pattern has significant impacts on ramp queue length; vehicle platoons released from the upstream signalized intersection tend to exacerbate ramp queue length. At metered ramps, the required queue storage length is found to be 5.7% of demand when demand is less than 500 vehicles per hour per lane (vphpl), or 3.9% when demand is greater than 500 vehicles per hour per lane (vphpl). In comparison, at metered connectors, the percent numbers are 4.7 and 2.1%, respectively.}, number={7}, journal={Transportmetrica A: Transport Science}, publisher={Informa UK Limited}, author={Yang, Guangchuan and Tian, Zong and Xu, Hao and Wang, Zhongren and Wang, Daobin}, year={2017}, month={Oct}, pages={543–561} }
 @article{yang_tian_xu_wang_2016, title={Queue length estimation at metered freeway-to-freeway connectors}, volume={50}, DOI={10.1002/atr.1436}, abstractNote={Summary}, number={8}, journal={Journal of Advanced Transportation}, publisher={Wiley}, author={Yang, Guangchuan and Tian, Zong and Xu, Hao and Wang, Daobin}, year={2016}, pages={1912–1924} }
 @article{yang_tian_xu_wang_2016, title={Recommendations for Acceleration Lane Length for Metered On-Ramps}, volume={2588}, DOI={10.3141/2588-01}, abstractNote={ AASHTO’s A Policy on Geometric Design of Highways and Streets (Green Book) is currently used by most state departments of transportation in the United States in determining the design length of acceleration lanes of metered on-ramps; however, the recommended acceleration lengths have not been updated for several decades. This study aimed to develop a method for determining acceleration lengths at metered on-ramps. Vehicle location versus time information was collected via parallel cameras at seven metered on-ramps in California; then, a piecewise constant acceleration model was proposed to calculate the spot speeds of individual samples at predetermined locations. The percentile distance-versus-speed profiles at each ramp were built, and regression models were generated to predict the required acceleration length at a given merge speed. The 85th percentile data were recommended as the minimum acceleration length to accommodate most drivers in accelerating to a safe merging speed. The new recommendation was compared with the existing guidance in the Green Book. On the basis of 1,658 individual samples, it was found that the recommended acceleration lengths were shorter than the Green Book guidelines by 10% to 35%. Also, results showed that acceleration lengths for tractor trailer trucks were approximately 60% greater than the Green Book guidelines. }, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={SAGE Publications}, author={Yang, Guangchuan and Tian, Zong and Xu, Hao and Wang, Zhongren}, year={2016}, month={Jan}, pages={1–11} }
 @article{yang_xu_wang_tian_2016, title={Truck acceleration behavior study and acceleration lane length recommendations for metered on-ramps}, volume={5}, DOI={10.1016/j.ijtst.2016.09.006}, abstractNote={This paper investigated the actual truck acceleration capability at metered on-ramps. Truck acceleration performance data were collected through a video-based data collection method. A piecewise constant acceleration model was employed to capture truck acceleration characteristics. It was found that the existing acceleration length will affect truck drivers’ acceleration behavior. At the taper type ramp that has limited acceleration distance, acceleration profile indicated a decreasing trend with distance. While for the ramp with an auxiliary lane that has sufficient acceleration distance, it was found that the acceleration behavior is to have a high acceleration rate in the beginning, then acceleration rate decrease with speed increase, and high acceleration rate again as drivers approach the merging area. Field data show that the truck acceleration performance data documented in the ITE’s (Institute of Transportation Engineers) “Traffic Engineering Handbook” are much lower than the field collected data. Also, based on the regression analysis of speed versus distance profiles, it was found that the AASHTO’s (American Association of State Highway and Transportation Officials) Green Book acceleration length design guidance is insufficient to accommodate trucks at metered on-ramps. The required acceleration lengths for medium and heavy trucks are approximately 1.3 and 1.6 times of the Green Book design guideline, respectively.}, number={2}, journal={International Journal of Transportation Science and Technology}, publisher={Elsevier BV}, author={Yang, Guangchuan and Xu, Hao and Wang, Zhongren and Tian, Zong}, year={2016}, month={Oct}, pages={93–102} }
 @article{yang_xu_tian_wang_2016, title={Vehicle Speed and Acceleration Profile Study for Metered On-Ramps in California}, volume={142}, DOI={10.1061/(asce)te.1943-5436.0000817}, abstractNote={Ramp metering has been proven as an effective freeway-management strategy; however, one of the critical challenges in design and operation of ramp metering is the lack of up-to-date design guidance for acceleration lanes. This paper aims to investigate the actual acceleration characteristics for metered on-ramps with various geometric features and also figure out speed profiles to guide the design of acceleration-lane length. A piecewise-constant acceleration model, which assumes vehicles making uniformly accelerated motion within each short space or time interval, was employed to model vehicle acceleration characteristics. The approach of using distance versus speed profiles for acceleration-length design was also introduced. RESULTS show that acceleration rate at metered on-ramps is not constant; vehicles usually accelerate at a higher acceleration rate when speed is lower and vice versa. It was observed that taper ramps usually produce higher acceleration rates than ramps with an auxiliary lane, and existing acceleration length would also affect drivers' acceleration behavior. Finally, this study pointed out that the acceleration performance data documented in the AASHTO Green Book, which are now widely employed by several state DOTs in the United States as acceleration length design guidance for metered on-ramps, is approximately 1.7 times greater than the value measured at typical taper-type metered on-ramp in California. Language: en}, number={2}, journal={Journal of Transportation Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Yang, Guangchuan and Xu, Hao and Tian, Zong and Wang, Zhongren}, year={2016}, month={Feb}, pages={04015046} }
 @article{yang_xu_tian_wang_zhao_2015, title={Acceleration Characteristics at Metered On-Ramps}, volume={2484}, DOI={10.3141/2484-01}, abstractNote={ Vehicle acceleration capability is an important parameter for traffic operation analysis, traffic simulation, and transportation facilities design. Most of the existing studies on acceleration characteristics, however, do not fully represent the realistic traffic conditions or are based on outdated data; these deficiencies may result in errors in modeling vehicle acceleration capability. In this paper, actual acceleration characteristics at metered on-ramps were investigated according to field data collection and analysis. With the assumption that vehicles make uniformly accelerated motion in each short space or time interval, the entire acceleration length was partitioned into several short segments. Then, video cameras, magnetic counters, or both were used to document the spot speed at predetermined locations; accordingly, distance–acceleration profiles of various ramp configurations were determined. Results showed that the acceleration rate at metered on-ramps was not constant; vehicles usually accelerated at a higher acceleration rate when the speed was lower and vice versa, and the maximum acceleration rate usually occurred at about 50 to 100 ft downstream from the stop bar. Also, a ramp with taper merging configuration usually produced higher acceleration rates than did a parallel merging ramp. This study also pointed out that acceleration rates documented in the AASHTO Green Book, widely used by most state departments of transportation in the United States as the acceleration length design guidance for metered on-ramps, were much lower than the values measured at existing metered on-ramps. }, number={1}, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={SAGE Publications}, author={Yang, Guangchuan and Xu, Hao and Tian, Zong and Wang, Zhongren and Zhao, Yue}, year={2015}, month={Jan}, pages={1–9} }
 @article{zhongyi_guangchuan_2013, title={Feasibility of Unconditional Transit Signal Priority Considering Delay Savings at Signalized Intersections: A Case Study of Dalian BRT Line No.1}, volume={96}, DOI={10.1016/j.sbspro.2013.08.094}, abstractNote={Active transit signal priority (TSP) is a useful tool to remove or minimize control delay for buses at signalized intersections and consequently improve the performance of bus service. Conditional TSP has been proofed to be an effective measure with fewer impacts to non-prioritized traffic, and aroused increasingly research interests and implementation in European and North American cities nowadays. However, the implementation of conditional TSP requires a sophisticated mechanism for examining the schedule deviation of priority required buses, as well as scanning traffic operational conditions at network level. By contrast, unconditional TSP is a less costly and easier measure for implementation, because it gives priority to every required bus without considering its schedule deviation. The critical argument on unconditional TSP is its adverse impacts to non-prioritized traffic, particularly during peak hours. To determine the threshold for implementing unconditional TSP, in this paper, theoretical analysis based on signal display graphs of differential TSP granting strategies was undertaken to estimate delay savings and increments for prioritized and non- prioritized approaches respectively. In the next step, Dalian BRT line was taken as an example to verify the feasibility of unconditional TSP based on the proposed theory. Results show that unconditional TSP is feasible during off-peak hours, while for peak hours, feasibility of unconditional TSP mainly depended on the traffic volume of each approach.}, journal={Procedia - Social and Behavioral Sciences}, publisher={Elsevier BV}, author={Zhongyi, ZUO and Guangchuan, YANG}, year={2013}, month={Nov}, pages={828–837} }
 @article{modeling modal shift of car travelers to buses based on public transport priority_2012, journal={Journal of Transportation System Engineering and Information Technology}, year={2012} }
 @inproceedings{zuo_yang_shao_2010, title={Design of Signal Timing Optimization Based on the Unsymmetrical Traffic Flow of Signalized Intersections}, DOI={10.1061/41123(383)34}, abstractNote={The operational condition of traffic flow and capacity of a signalized intersection to some extent depends on the setting of signals; the better the signal timing, the greater the capacity of intersections. This paper analyzed the survey data of Wuyi Road-Southwest Road intersection, Dalian, calculated the current capacity and delays of the intersection, then re-organized traffic flow according to the practical traffic demand and designed an unsymmetrical five-phase signal timing scheme based on the principle of overlap phase. The calculation showed that using the improved signal timing scheme, it will result in a moderate increase in traffic capacity (21.9%) and an significant decrease of delays (53.1%).}, booktitle={Traffic and Transportation Studies 2010}, publisher={American Society of Civil Engineers}, author={Zuo, Zhongyi and Yang, Guangchuan and Shao, Chunfu}, year={2010}, month={Jul} }