Travel Behavior

Development and Assessment of Selected Mobility Applications for VII: Principal Findings

Shladover, Steven E
Lu, Xiao-Yun
Nowakowski, Christopher
2011

This project has shown how connected vehicle systems, based on vehicle-vehicle and vehicle-infrastructure communication and coordination, can support the development of mobility-enhancing applications with the potential to transform the performance of the road transportation system. Three separate mobility-enhancing applications were developed, simulated, and tested, and their expected mobility benefits were estimated using simulations. Cooperative adaptive cruise control was shown to have a high potential for user acceptance, and when applied at the gap settings chosen by representative...

California Intersection Decision Support: A Driver-Centered Approach to Left-Turn Collision Avoidance System Design

Bougler, Bénédicte
Cody, Delphine
Nowakowski, Christopher
2008

Currently, Federal and State governments are partnering with private industries and academia institutions to pursue the deployment of intersection decision support (IDS) and cooperative intersection collision avoidance systems (CICAS), which seek to combine infrastructure-based and vehicle-based functions to provide optimal solutions for roadway users. The overall (IDS) research plan was constructed to explore the requirements, tradeoffs assessment, and technology investigations necessary to define a Cooperative Intersection Collision Avoidance System. This report is the third report on...

Onboard Monitoring and Reporting for Commercial Vehicle Motor Safety

Cooper, Doug
Dickey, Sue
Johnston, Scott
Kim, ZuWhan
Koo, Thomas
Kretz, Paul
Kuhn, Kenny
Lu, Xiao-Yun
Margulici, JD
Misener, James A.
Nowakowski, Christopher
Robin, Jerry
Spring, John
Walker, Martin
2007

This final report describes the process and product from the project, Onboard Monitoring and Reporting for Commercial Motor Vehicle Safety (OBMS), in which a prototypical suite of hardware on a Freightliner Century Class truck was developed and tested.The OBMS suite allows for online measurement of a set of driving characteristics which are indicators of unsafe driving behavior. These characteristics include speed, following distance, lane keeping performance, safety belt use, and the use of turn signals. Feedback can be provided to the driver, either directly via real time feedback or...

Evaluation of Traffic and Environment Effects on Skid Resistance and Safety Performance of Rubberized Open-grade Asphalt Concrete

Oh, Soon Mi
Ragland, David R.
Chan, Ching-Yao
2010

Wet pavement-related collisions represent a significant traffic safety concern, due in part to the lack of adequate friction between tire and pavement, known as skid resistance. State agencies employ a skid number (SN) system, based on a standard test procedure in which a locked wheel is towed at 40 mph and the skid number (SN40) is calculated from the measured resistance. SN40 is used as a reference value for speeds both greater than and less than 40 mph. For most Departments of Transportation (DOTs) in the nation, excluding California, pavements for which the SN40 is below 30 are deemed...

Improving Mobility Through Enhanced Transit Services: Case Studies for Transit-Taxis

Widmann, Joshua H.
Miller, Mark A.
2006

This report, an interim deliverable for Task Orders 5408 and 6408: “Improving Mobility through Enhanced Transit Services”. Thus far in the study we have performed a review of the literature and conducted a small number of site-specific case studies for transit agencies in North America identified from the literature review as either currently having or in the past having had transit-taxi service implemented in their agency’s jurisdiction. We initially classified alternative concepts of transit-taxis into a typology of three service design options based on a review of the literature: 1)...

Medium Access Control Protocol Design for Vehicle-Vehicle Safety Messages

Xu, Qing
Mak, Tony
Ko, Jeff
Sengupta, Raja
2005

We propose a Medium Access Control (MAC) protocol design for a vehicle to send safety messages to other vehicles. We develop a QoS model for safety messages consistent with the active safety systems literature. Each message has a range and useful lifetime. The QoS target is to have each message be received with high probability within its specified lifetime by each vehicle within its specified range. The protocol design is based on rapidly re-broadcasting each message multiple times within its lifetime in combination with the 802.11 DCF. This makes the design compatible with the emerging...

Evaluation of Incorporating Hybrid Vehicle Use of HOV Lanes

Brownstone, David
Chu, Lianyu
Golob, Tom
Nesamani, K.S.
Recker, Will
2008

This report presents a method to investigate the operational and environmental effects of the policy of allowing qualified single-occupancy hybrid vehicles to use dedicated High-Occupancy Vehicle (HOV)/carpool lanes in California.. The method combines the traditional planning method with microscopic simulation modeling. The planning method is used for demand estimation and analysis and the microscopic traffic simulation modeling method is used for accurate measures of the system. The study employs a microscopic traffic simulation model that is capable of evaluating the HOV/hybrid system...

Evaluating System ATMIS Technologies Via Rapid Estimation Of Network Flows: Final Report

Moore, II, James E.
Kim, Geunyoung
Cho, Seongdil
Hu, Hsi-hwa
Xu, Rong
1997

This report studies how flows in large scale transportation networks can be subjected to rapid estimation. It describes an efficient transportation network analysis (TNA) procedure that provides the system-wide changes of network flows under numerous scenario earthquakes. The first objective of this research is to provide reliable estimates of network flows with respect to changes in transportation networks, and to incorporate these changes to the decision-making procedures used by the California Department of Transportation (Caltrans) in making bridge retrofit decisions. The second...

Considering Risk-Taking Behavior in Travel Time Reliability

Recker, Will
Chung, Younshik
Park, Jiyoung
Wang, Lesley
Chen, Anthony
Ji, Zhaowang
Liu, Henry
Horrocks, Matthew
Oh, Jun-Seok
2005

Travel time variability is increasingly being recognized as a major factor influencing travel decisions and, consequently, as an important performance measure in transportation management. In this research project, we examine a number of questions related to travel time variability: How should travel time variability be quantified at both the section level as well as at the route level?; How do travelers value travel time and its reliability?; How much does the travel time reliability contribute to travelers' route choices?; How much variation is there in travelers' preferences regarding...

Cooperative Adaptive Cruise Control: Testing Drivers’ Choices of Following Distances

Nowakowski, Christopher
Shladover, Steven E.
Cody, Delphine
Bu, Fanping
O'Connell, Jessica
Spring, John
Dickey, Susan
Nelson, David
2011

A Cooperative Adaptive Cruise Control (CACC) system has been developed by adding a wireless vehicle-vehicle communication system and new control logic to an existing commercially available adaptive cruise control (ACC) system. The CACC is intended to enhance the vehicle-following capabilities of ACC so that drivers will be comfortable using it at shorter vehicle-following gaps than ACC. This can offer a significant opportunity to increase traffic flow density and efficiency without compromising safety or expanding roadway infrastructure.This report describes the design and implementation...