1.Identify potential VMS messaging factors that may affect motorist comprehension of messages.
2.Design and conduct lab simulation experiments to examine motorists’ responses to various combinations of these factors.
3.Carry out field studies on selected routes and compare results with those obtained from lab simulation experiments.
4.Analyze results, correlate lab simulations with field studies, and make recommendations and guidelines to highway authorities.
Highway
It is recognized that variable message signs (VMS) play a key role in intelligent transportation systems, not only to alleviate acute problems caused by road work and accidents, but also to help enhance driving safety. Highway authority in Rhode Island has, since late 1990’s, been using VMS to communicate real-time traffic information and travel advice to motorists. As this method becomes increasingly used, it is important to present sign messages that can be comprehended correctly and promptly by motorists, especially in high-volume traffic and construction/repair zones. Due to restricted VMS space, even simple ideas can be difficult to communicate to motorists moving at highway speeds. Properly designed sign messages can spell the difference between understanding and confusion. The effectiveness of VMS messages depends on sign design, message design, and display format. Previous projects sponsored by URITC and RIDOT studied sign design and obtained significant findings.
This project addresses the issues of message design and display format. It will evaluate the effectiveness of information delivered by a variety of VMS messaging with various wordings and display formats. This evaluation will be stratified by drivers’ demographics (gender, age, and linguistic ability), and driving speed. Special focus will be placed on the elder population and ethnic groups for whom English is not their primary language. Two study approaches will be employed in the project, a lab simulation approach and a field study approach. The former will take place in the Motorist Performance Lab at URI. Virtual driving experiments will be devised to capture subjects’ responses to different VMSs appearing at road side in a virtual driver’s prospect moving at highway speed. The latter will be carried out on selected highway segments where VMSs are present. In-vehicle digital camcorder will be installed to capture drivers’ responses. Results obtained from the field study will be compared with those from the lab simulation with the intention to find a correlation between them. From this study, specific recommendations will be made to industry, highway authorities, and traffic management to help them optimize the message design and use of VMSs to enhance driving safety.
The project will take eighteen months to complete. Specific tasks addressing each of the project’s objectives are described below.
Task 1. Identify potential VMS messaging factors that may affect motorist comprehension of messages.
This task involves a further review of existing research guidelines on VMS reported in the literature. It will gather information on current VMS operation practices in Rhode Island and neighboring states. It will conduct focus group studies to obtain the general public’s opinion about VMS messaging. Consultation with traffic engineers, ITS specialists, and other researchers in this field will be frequently sought during this development. A summary of existing research guidelines, current state practices on VMS messaging, and drivers’ opinion will be produced. These activities will help target potential factors in VMS messaging that may affect motorist comprehension of message and help select factors to be included in the experiments. The factors will be selected to provide new information specifically applicable to Rhode Island and neighboring states. Specific settings associated with each selected factor will also be determined at this stage.
Task 2. Design and conduct lab simulation experiments to examine motorists’ responses to various combinations of these factors.
The mission here is to develop simulated, virtual driving lab experiments to explore the factors identified and to carry out the experiments. It will use the MS Visual Basic platform as the major tool in developing the VMS driving simulation. In this development, digital videos will be taken to capture a driver’s view of driving at highway speed. Videos will be transferred into a computer and be edited to create a driving background. Computer generated VMS animations will then be superimposed onto the digitized driving background video and be projected onto a semi-circular wall screen. Test subjects, sitting in the driver’s seat of the test vehicle, will have a virtual driver’s view of driving at highway speed. Animated VMS stimuli will appear at roadside as they are seen in actual driving but with higher frequency. Test subjects need to press certain keys on a keypad mounted on the steering wheel to signify their comprehension of the message. Administrative computer programs will be developed to control the execution of these experiments and to collect subjects’ responses.
Task 3. Conduct field studies on selected routes and compare results with those obtained from lab simulation experiments.
Test routes in the field study will be carefully chosen to include several VMS displays on the route that are comparable to some of those tested in the lab simulation. Test subject, driving the test vehicle at an instructed speed, will make vocal response to VMS as soon as she/he comprehended the message. The in-vehicle digital video camcorder will capture the driving scene including VMS and the subject’s responses. Through a frame-by-frame analysis of the video, the response time to each VMS will be obtained. Results found from the field study will be compared with those obtained from the simulation study.
Task 4. Analyze results, correlate lab simulations with field studies, and make recommendations and guidelines to highway authorities.
Statistical analyses will be performed to analyze the experiment results. Analysis of variance (ANOVA) procedures, multiple range tests, and response surface methodology will be employed to identify significant VMS messaging factors and/or their interactions in the lab simulation experiments. Optimized settings for individual factors and their combinations will be determined. Regression techniques will be applied to explore the correlations between the field study results and the lab simulation results. If meaningful correlations were found, models gauging motorist response to VMS in real driving can then be developed through simulated lab experiments. Based on these analyses, interpretation and conclusions will be drawn and specific recommendations made. Findings found from this project will be compared with findings found from other relevant studies. Guidelines for proper VMS messaging will be compiled to enhance motorists’ understanding and driving safety. Suggestions for future research will be provided.
1. (9/03-12/03)Perform further reviews on existing studies, gather info on current VMS practices, and identify VMS messaging factors to be included in the experiment.
2. (11/03-03/04)Take driving videos, synthesize the videos with computer generated VMS animations, and develop computer programs to conduct the simulation.
3. (03/04-08/04)Recruit subjects with different demographic backgrounds and carry out the lab simulation experiments.
4. (08/04-11/04)Select test routes for field study, conduct field studies, and compare results with those from lab simulation experiments.
5. (11/04-03/05)Perform statistical analyses on experiment results, correlate field study results with lab simulation, and make recommendations and guidelines.
$151,103.00 ($100,735.00 Yearly)
Students will be recruited to carry out different tasks of this project via independent studies, class projects, internships, and thesis researches. Both undergraduate and graduate engineering students will be involved in these activities. Special efforts will be made to attract minority and female students to participate in various phases of this project.
Variable message signs are critical to the success of the intelligent transportation system. They provide a direct communication between highway management system and human drivers. This research project is clearly one of the foci of ITS and is linked with many other research project on ITS. The design of experiment approach employed in this project will provide a reliable methodology that can help improve quality and credibility in highway system management, and enhance safety and comfort in driving. In general, it will promote a better understanding about VMS in the human/ITS interface. We anticipate this project to benefit the highway management system as a whole, stimulate more studies related to this topic, and help accomplish the mission of the URI Transportation Center.
During the project’s development, web pages will be constructed to post the progress made and findings found to allow communications with the practitioners and other researchers. Upon completion, a final report will be prepared containing methodologies, analytical summaries, specific recommendations, and accompanying computer outputs. They may be distributed to all interested parties upon the approval of URITC. Presentations on project findings will be made to URITC, state and federal DOT. Arrangement will be made to transfer the computer simulation programs, experimental design protocols, and analytical results to URITC. Besides printed reports, this information will also be packaged into CDs and be published through the web with URITC permission. The findings of this project will be shared with the transportation engineering community as conference presentations and journal publications. Special efforts will be made to present the project development and findings to high school students to stimulate their interest in transportation engineering research.
Intelligent transportation system (ITS) is the newest technology researched and implemented by transportation management and engineers to improve highway driving safety. The US DOT as well as the state DOT are continuously looking to add new technologies and system to help them use the current facilities more effectively. The success of the intelligent transportation system implementation is ultimately contingent upon good interface between the systems and its users. VMS provides a direct interface between highway management system and human drivers and is a critical element in the intelligent transportation system. This research project is clearly one of the foci of ITS and linked with many other research project on ITS. The approach taken in this project provides a reliable methodology that can help improve quality and credibility in highway system management, enhance safety and comfort in driving, and promote a better understanding about VMS and the human/ITS interface issues. The involvement of graduate and undergraduate students in this project will help equip our future transportation engineers with the practical knowledge and experience to apply statistical tools on solving transportation related problems. We anticipate that this project will benefit the highway management system, ITS researchers, and motorists as a whole, stimulate more studies related to this topic, and help attain the mission of the URI Transportation Center. It is believed that this project will lead to many interesting findings in this field and stimulate more research in the area.
Variable message signs, Human factors, Message design, Driving safety