Connected Vehicle Infrastructure University Transportation Center
The final report for Next Generation Transit Signal Priority with Connected Vehicle Technology, submitted by Dr. Jia Hu, Dr. Young Jae-Lee, Dr. Byungkyu Brian Park, and Seyedehsan Dadvar has been released.
Report Abstract:
This project utilized connected vehicle (CV) technology allowing two-way communication among vehicles and infrastructure to develop a next-generation Transit Signal Priority (TSP) system that does not have to rely on conventional TSP sensors. The research team extended a previously proposed TSP system based on CV technology (TSPCV) to handle conflicting requests and to coordinate passage between intersections in a travel corridor. The proposed TSP mechanisms minimize installation and maintenance costs by eliminating the need for local agencies to perform a level of service (LOS) study and/or volume/capacity (v/c) ratio for potential TSP intersections before installation. Simulation-based evaluation results showed that, compared to conventional TSP mechanisms, the proposed TSP logic reduces bus delays between 5% and 48% (TSPCVM) and decreases the delay of a bus progressing along a corridor between 35% and 68% (TSPCV-C). The range of improvement corresponds to the four different v/c ratios tested, which were 0.5, 0.7, 0.9 and 1.0. In most cases, the proposed TSP logic caused no negative effects.
A field experiment conducted on the Connected Vehicle test bed on the Virginia Smart Road, located at the Virginia Tech Transportation Institute (VTTI) in Blacksburg, Virginia, validated the performance of the proposed TSPCV system. The TSPCV algorithm provided green traffic signal timing to buses with different arrival times with a 100% success rate. It also reduced delays for a bus with a speed of 45 mph and a traffic signal with a 90-second cycle length and 30 seconds of green time by as much as between 32% and 75%. Moreover, the field experiment showed that two Global Positioning System (GPS) devices (regular and differential) performed almost identically and, in an aggregate sense, the difference in their performance was not statistically significant. This finding facilitates the large-scale implementation of TSP, since regular GPS devices are much cheaper than differential GPS devices and operated just as well for TSPCV.
Click here to learn more about this project and read the final report.
The final report for Connected Motorcycle Crash Warning Interfaces, submitted by Dr. Miao Song, Dr. Shane McLaughlin, and Dr. Zachary Doerzaph has been released.
Report Abstract:
Crash warning systems have been deployed in the high-end vehicle market segment for some time and are trickling down to additional motor vehicle industry segments each year. The motorcycle segment, however, has no deployed crash warning system to date. With the active development of next generation crash warning systems based on connected vehicle technologies, this study explored possible interface designs for motorcycle crash warning systems and evaluated their rider acceptance and effectiveness in a connected vehicle context. Four prototype warning interface displays covering three warning mode alternatives (auditory, visual, and haptic) were designed and developed for motorcycles. They were tested on-road with three connected vehicle safety applications – intersection movement assist, forward collision warning, and lane departure warning – which were selected according to the most impactful crash types identified for motorcycles. It showed that a combination of warning modalities was preferred to a single display by 87.2% of participants and combined auditory and haptic displays showed considerable promise for implementation. Auditory display is easily implemented given the adoption rate of in-helmet auditory systems. Its weakness of presenting directional information in this study may be remedied by using simple speech or with the help of haptic design, which performed well at providing such information and was also found to be attractive to riders. The findings revealed both opportunities and challenges of visual displays for motorcycle crash warning systems. More importantly, differences among riders of three major motorcycle types (cruiser, sport, and touring) in terms of riders’ acceptance of a crash warning interface were revealed. Based on the results, recommendations were provided for an appropriate crash warning interface design for motorcycles and riders in a connected vehicle environment.
Click here to learn more about this project and read the final report.
The final report for Connected Motorcycle Crash Warning Interfaces, submitted by Reginald Viray, Alex Noble, Dr. Zac Doerzaph, and Dr. Shane McLaughlin has been released.
Report Abstract:
This project characterized the performance of Connected Vehicle Systems (CVS) on motorcycles based on two key components: global positioning and wireless communication systems. Considering that Global Positioning System (GPS) and 5.9 GHz Dedicated Short-Range Communications (DSRC) may be affected by motorcycle rider occlusion, antenna mounting configurations were investigated. In order to assess the performance of these systems, the Virginia Tech Transportation Institute’s (VTTI) Data Acquisition System (DAS) was utilized to record key GPS and DSRC variables from the vehicle’s CVS Vehicle Awareness Device (VAD). In this project, a total of four vehicles were used where one motorcycle had a forward mounted antenna, another motorcycle had a rear mounted antenna, and two automobiles had center-mounted antennas. These instrumented vehicles were then subject to several static and dynamic test scenarios on closed test track and public roadways to characterize performance against each other. Further, these test scenarios took into account motorcycle rider occlusion, relative ranges, and diverse topographical roadway environments.
From the results, both rider occlusion and approach ranges were shown to have an impact on communications performance. In situations where the antenna on the motorcycle had direct line-of-sight with another vehicle’s antenna, a noticeable increase in performance can be seen in comparison to situations where the line of sight is occluded. Further, the forward-mounted antenna configuration provided a wider span of communication ranges in open-sky. In comparison, the rear-mounted antenna configuration experienced a narrower communication range. In terms of position performance, environments where objects occluded the sky, such as deep urban and mountain regions, relatively degraded performance when compared to open sky environments were observed.
Click here to learn more about this project and read the final report.