Study of Delay Calculation for Diverging Diamond Interchange and Safety Assessment of Ecodriving on Following Traffic
Diverging diamond interchanges (DDI) have been proved to outperform other types of diamond interchanges in terms of safety, cost-effectiveness and efficiency, but few research efforts have been done to conduct the analytic calculation of delay, with which optimization of timing plans can be acquired more efficiently. This paper develops the control strategies based on the introduction of overlap and offset analysis, which provide a uniform representation of sequences for DDI signal control. Based on the developed timing plan then the delay calculation equations are put forward and results show the calculation fit simulation very well with R-Square to be 0.9949 for total delay of those two directions.
Ecodriving aims to achieve the best fuel efficiency by guiding vehicles travel at planned and optimized speed trajectories. This study opens the door for safety concerns for following normal driving vehicles (FNVs) when following ecodriving vehicles (EVs). To examine the safety issues under different circumstance. Three road elements: initial signal status, ambient vehicles and speed limit along with three EV elements: SpeedTolimit, DistanceToStoplight and acceleration were chosen as potential influential elements, and time to collision (TTC) was selected as the dependent variable. Therefore, six testing scenarios and six baseline were designed and implemented using a drive safety DNS-250 simulator. 29 drivers participated in the driving simulator study. The results show the aforementioned road elements and EV elements have significant influence on TTC of FNV in different testing parts. Therefore, these finding can be used as guidance for future ecodriving algorithm design and implementation.