Transportation Research Record: Journal of the Transportation Research Board ( IF 1.7 ) Pub Date : 2021-01-15 , DOI: 10.1177/0361198120985853 Michael H. Sheffield 1 , Grant G. Schultz 2 , David Bassett 3 , Dennis L. Eggett 4
An analysis was performed to evaluate the impact of changing the transit signal priority (TSP) requesting threshold on bus performance and general traffic, using field-generated data exclusively. Route 217, a conventional bus route that uses a dedicated short-range communication (DSRC)-based TSP system as part of its normal day-to-day operations, was analyzed over a three-month period from May 2019 through August 2019. The requesting thresholds evaluated for Route 217 were 3, 2, and 0 min, which stipulate how far behind schedule the bus must be to request TSP. For each requesting threshold, bus performance was evaluated through on-time performance (OTP), schedule deviation, travel time, and dwell time, while the traffic analysis was performed by evaluating split failure, change in green time, and the frequency at which TSP was served. A combination of observational and statistical analyses concluded with convincing evidence that OTP, schedule deviation, and travel time improve as the requesting threshold approaches zero with negligible impacts on general traffic. As the requesting threshold changed from 3, to 2, to 0 min, OTP increased 2.0% and 2.5%, respectively; mean schedule deviation improved by 15.9 s and 20.9 s, respectively; and travel time decreased at 75% of timepoints. Meanwhile, negative impacts to traffic occurred if an increase in split failure was measured after TSP was served, a phenomenon observed a maximum of once every 43 min. Thus, it is concluded that bus performance improves as the requesting threshold approaches zero with inconsequential impacts on general traffic.
中文翻译:
公交信号优先请求阈值的灵敏度分析及其对公交性能和一般交通的影响
专门使用现场生成的数据进行了分析,以评估更改公交信号优先级(TSP)请求阈值对公交车性能和一般交通的影响。从2019年5月到2019年8月的三个月期间,对217号公路进行了分析,这是一条常规的公交路线,使用基于专用短程通信(DSRC)的TSP系统作为其日常正常运营的一部分。为217号路线评估的请求阈值分别为3分钟,2分钟和0分钟,这些阈值规定了公交车请求TSP的时间必须晚于时间表。对于每个请求的阈值,通过准时性能(OTP),时间表偏差,行驶时间和停留时间来评估总线性能,而流量分析是通过评估拆分故障,绿灯时间变化以及TSP的频率来进行的被送达。观察性分析和统计分析的组合得出的令人信服的证据表明,随着请求阈值接近零,OTP,日程偏差和旅行时间得到改善,对一般流量的影响可忽略不计。随着请求阈值从3分钟变为2分钟到0分钟,OTP分别增加了2.0%和2.5%;日程平均偏差分别提高了15.9 s和20.9 s;旅行时间减少了75%。同时,如果在运输TSP后测量分裂失败的增加,则会对流量产生负面影响,这种现象每43分钟最多观察到一次。因此,可以得出结论,当请求阈值接近零时,总线性能会提高,而对一般流量的影响不大。行程偏离,行程时间缩短,因为要求的门槛接近零,对一般流量的影响可忽略不计。随着请求阈值从3分钟变为2分钟到0分钟,OTP分别增加了2.0%和2.5%;日程平均偏差分别提高了15.9 s和20.9 s;并且旅行时间减少了75%。同时,如果在运输TSP后测量分裂失败的增加,则会对流量产生负面影响,这种现象每43分钟最多观察到一次。因此,可以得出结论,当请求阈值接近零时,总线性能会提高,而对一般流量的影响不大。行程偏离,行程时间缩短,因为要求的门槛接近零,对一般流量的影响可忽略不计。随着请求阈值从3分钟变为2分钟到0分钟,OTP分别增加了2.0%和2.5%。日程平均偏差分别提高了15.9 s和20.9 s;并且旅行时间减少了75%。同时,如果在运输TSP后测量分裂失败的增加,则会对流量产生负面影响,这种现象每43分钟最多观察到一次。因此,可以得出结论,当请求阈值接近零时,总线性能会提高,而对一般流量的影响不大。OTP分别增长2.0%和2.5%;日程平均偏差分别提高了15.9 s和20.9 s;旅行时间减少了75%。同时,如果在运输TSP后测量分裂失败的增加,则会对流量产生负面影响,这种现象每43分钟最多观察到一次。因此,可以得出结论,当请求阈值接近零时,总线性能会提高,而对一般流量的影响不大。OTP分别增长2.0%和2.5%;日程平均偏差分别提高了15.9 s和20.9 s;并且旅行时间减少了75%。同时,如果在运输TSP后测量分裂失败的增加,则会对流量产生负面影响,这种现象每43分钟最多观察到一次。因此,可以得出结论,当请求阈值接近零时,总线性能会提高,而对一般流量的影响不大。