Return to search

Modeling Connected and Autonomous Vehicles Impacts on Mobility and Safety in Work Zones

This study embarked with focus on the analysis, to quantify the potential impacts of varying market penetration rates (MPR) of connected and autonomous vehicles (CAVs) on the traffic network mobility and safety in construction work zones. The prospects for success were evaluated in three ways: (1) understanding the potential benefits of CAV in improving the travel time as result of work zone impacts; (2) reducing the delay and queues by improved time headway; and (3) safety benefits of the autonomous vehicles at varying market penetration rates by lowering the levels of incident probabilities and the Time-to-Collision. CAV market penetration rates, from 10% to 100%, in an increment of 10%, were used in the assessment of the potentials for these vehicles to improve the traffic performance in work zones. The effects at low and high penetration rates were assessed to evaluate the improvements on traffic mobility and overall network safety in the work zone when compared with traffic stream of only conventional vehicles. The motivation of this research comes primarily from the consideration of deployment and full utilization of connected autonomous vehicles in the real traffic world, most especially in the work zones which typically require altered road geometry such as lane closure and reduced speed areas. With varied market penetration rates (relative composition in the traffic) of the connected autonomous vehicles, the research question is premise on the actualization and an assessment of the safety benefits and improvement of network performance. VISSIM, a microscopic traffic simulation software, was used extensively in the analysis of the traffic conditions because it is able to represent different driver behaviors and interaction between vehicles. A broad literature review in the area of microsimulation of connected and autonomous vehicles was conducted to examine the effects of automated vehicles effects on traffic operations. Two different work zone locations were considered for this study: one is a long stretch of work zone on Interstate 44 in Missouri; and the other is a short stretch on Interstate 95 in Jacksonville, Florida. The study sites do not have similar traffic characteristics and geometry and hence the impacts of CAVs on both sites were evaluated independently. Different driver behavior models comprising cautious, moderate and assertive types, were considered for the study. After a careful analysis of the impacts of the different levels of CAV capabilities on the two work zones, findings show that CAVs have potential benefits of improving the traffic situations in work zones. For instance it was observed that even at low MPR of 10% CAVs, travel time was reduced by 14%. A monotonic improvement in travel time was observed across all CAV market penetrations. Results also showed that the benefits of travel CAVs were only noticeable when there is a high demand in traffic or during the peak period. No noticeable changes in traffic performance were observed when demand was low. Similar results were observed for impacts that CAVs have on both delays and queue length; this is because both of the measures of performance are related. When CAVs assumed the most cautious driver behavior models, results showed that the average vehicle delay was reduced, and there was a gradual improvement in delay as MPR increases. When market penetration approaches 100%, the work zone’s average vehicle delay could be reduced by a 70%. For the moderate (between cautious and aggressive) models, the average vehicle delay was greatly reduced. As CAV market penetrations approached 20%, similar results were achieved for the two scenarios of the moderate models that were evaluated. The results of the aggressive models appears to be more unrealistic, and reduction in delays very dramatic at lower market penetrations of CAVS, resulting in an 85% reduction in average vehicle delay as the CAV fleet reached 20%. A sensitivity analysis of the VISSIM driver behavior parameters will be necessary in this case to assess the impacts of such parameters on the traffic flow. In general, introduction of CAVs in the traffic stream lowered the average vehicle delays, however the resulting impacts vary across the different driver behavior models. The impacts on CAVs was also assessed for safety of the road users; the time-to-collision (TTC) and post encroachment time (PET) surrogate safety measures were employed to determine the effects of CAVs on the presence of conflicts. Findings from this study shows that as CAV market penetrations increase, the conflicts in the work zones reduced significantly. CAVs with more assertive driver behaviors indicated a higher percentage in conflict reductions even at lower market penetrations. Though the impacts vary for all the behavior models, it was observed that there is capability-wide safety benefits for CAV market penetrations. However, the proportion of conflicts in the severity zones increased with an increase in the CAV aggressiveness. / A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2018. / July 19, 2018. / Includes bibliographical references. / John Sobanjo, Professor Directing Thesis; Yassir AbdelRazig, Committee Member; Eren Erman Ozguven, Committee Member.
ContributorsSanusi, Fehintola B. (Fehintola Basirat) (author), Sobanjo, John Olusegun, 1958- (professor directing thesis), AbdelRazig, Yassir (committee member), Ozguven, Eren Erman (committee member), Florida State University (degree granting institution), FAMU-FSU College of Engineering (degree granting college), Department of Civil and Environmental Engineering (degree granting departmentdgg)
PublisherFlorida State University
Source SetsFlorida State University
LanguageEnglish, English
Detected LanguageEnglish
TypeText, text, master thesis
Format1 online resource (108 pages), computer, application/pdf

Page generated in 0.0022 seconds