Highway
This project intends to study the feasibility of employing graphics to aid the message display on dynamic message sign (DMS) system. DMS system has been recently deployed in Rhode Island and its neighboring states. Its objective is to provide drivers with real-time information and advice about roadway and traffic conditions to warrant safe and efficient driving on highways. Current DMS systems, though capable of displaying graphics, are primarily used to provide descriptive textual information. This study assesses the effects of graphics-aided messaging on drivers’ comprehension. It will study driver’s acceptance and interpretation of traffic advice displayed in both graphical and textual formats. It will identify effective graphical displays accompanying text messaging to be used in DMS systems.
The PIs have led several projects sponsored by URITC and RIDOT to study DMS/VMS sign design, message design, display format, message wording with regard to textual messages. This project extends the findings from previous projects and explores the use of graphics to enhance current DMS systems. It will evaluate the effectiveness of messaging delivered by DMS through the use of textual information, graphical information, and both. This evaluation will be stratified by drivers’ demographics and driving speed. A special focus will be placed on the elder population and ethnic groups whose primary language is not English. The study will examine drivers in the region via questionnaire surveys, driving simulations, and field studies to identify important factors in the design and deployment of graphics-aided DMS message displays. From these studies, it will identify the pros and cons of employing graphics in DMS messaging and recommend effective means to leverage the graphical display capability of DMS system to optimize its messaging display.
The project will take twelve months to complete. Specific tasks addressing each of the project’s objectives are described below.
Task 1 - Examine the feasibility of employing graphics in DMS messaging and determine factors to be considered in the simulation experiment.
This task involves a comprehensive review of existing research and literature related to the use of graphics in DMSs and the effects of such uses on drivers. It will gather information on current DMS operation practices in Rhode Island and neighboring states. Since some European countries have pioneered the use of graphics in their DMS systems, special efforts will be made to collect literature regarding their operation practices, assessments, and recommendations. Consultation with traffic engineers, ITS specialists, and other researchers in this field will be sought during this development. A summary of current practices and research findings on DMS messaging in the states and overseas will be produced. This summary will help assess the feasibility of employing graphics in DMS in this area and others. It will also help target potential factors in graphics-aided DMS messaging that may affect drivers’ comprehension. The factors to be included in the simulation experiments will be collectively determined by the Pis and collaborators from RIDOT, URITC and Daktronics. Specific settings associated with each selected factor will also be determined.
Task 2 - Gain insights into drivers’ understanding of graphics-aided messages and examine variation in drivers’ interpretation of these messages.
This task requires a survey on drivers’ opinions regarding their understanding and interpretation of graphics-aided messages and their preferences of graphical versus textual traffic information displays. A web-based questionnaire survey will be developed collectively by the Pis and the collaborators. Surveys will be conducted via the websites of URITC and will be opened to the general public. Subjects participating in the driving simulation experiment will be asked to complete the survey prior to their experiments. Through this survey, information regarding drivers’ understanding and interpretation of various graphical displays, influence of the graphics-aided messages on drivers’ route choice, and potential problems with the use of graphics in DMSs will be obtained. Participants will also be asked to provide certain demographic information including gender, age group, driving experience, driving frequency, and network familiarity. Together with findings from the first task, it is expected to provide a solid foundation to design the driving simulation experiment to effectively assess the pros and cons of graphics-aided DMS messaging.
Task 3 - Design and conduct driving simulation experiments to assess drivers’ response to various types of graphics-aided messages.
This task will develop a simulated, virtual driving experiment to explore various types of graphics-aided messages identified earlier. On the basis of the results of the literature review and questionnaire survey, draft graphics-aided DMS messages will be further tested in the Motorist Performance Laboratory through 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 graphical DMS animations will then be superimposed onto the digitized driving background video and be projected onto a wide screen. In its execution, an animated DMS stimulus will appear at the far end as a small dot slightly above the road. The small dot will increase in size and become an overhead DMS containing graphical and textual messages as it is seen in actual driving. A sequence of stimuli will be introduced in a random but controlled manner. A test subject, sitting in the driver’s seat of the test vehicle, will have a virtual driver’s view of driving at highway speed. The subject needs to press a certain key on a keypad mounted on the steering wheel to signify her/his comprehension of the message. Upon receiving a response from the test subject, the current display of DMS stimulus terminates. After a random elapsed time, the next stimulus appears. A series of full factorial experiments will be designed to test various factors in the driving simulation. Within-subject factors are selected to test: textual versus graphical message display, alternative designs for graphical display, color coded information, recognition of symbols, and acceptance of graphical route advices. Between-subject factors considered are: age, gender, driving experience, and primary language. A minimum of 36 subjects with different demographics will be recruited to participate in the experiments.
Task 4 - Conduct field studies to validate findings obtained from driving simulations.
This task intends to validate driving simulation results through field studies. With cooperation from RIDOT, a test route in the field study will be chosen to include several DMS displays that are comparable to some of those tested in the driving simulation. A test subject, driving the test vehicle at an instructed speed, will make verbal response to these DMSs as soon as she/he comprehended the message. An in-vehicle digital image and sound recorder will capture the driving scene including DMS and the subject’s verbal responses. The response time to each DMS will be obtained through a frame-by-frame analysis of the video. Subjects participated in the lab simulation will be invited to participate in the field study on a voluntary basis. Results obtained from the field study will be correlated with those obtained from the lab simulations. High correlations would indicate a strong validity of simulation results.
Task 5 - Analyze experiment results and make recommendations toward the design and deployment of graphics-aided DMSs.
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 factors and/or their interactions in the driving 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 and the driving simulation. If meaningful correlations were found, models gauging drivers’ response to graphics-aided DMS in real driving can then be developed through driving simulation 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 developing graphical information displays will be compiled to help deploy graphics-aided DMS system.
09/04-11/04
Examine the feasibility of employing graphics in DMS messaging and determine factors to be considered in the simulation experiment.
10/04 - 12/04
Survey drivers’ understanding of graphics-aided messages and examine variation in drivers’ interpretation of these messages.
01/05 - 05/05
Design and conduct driving simulation experiments to assess drivers’ response to various types of graphics-aided messages.
05/05 - 07/05
Select test routes for field study, conduct field studies, and compare results with those from driving simulation experiments.
07/05 - 09/05
Analyze experiment results and make recommendations toward the design and deployment of graphics-aided DMSs.
$123,955.29
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.
Dynamic message signs are critical to the success of an intelligent transportation system. They provide a direct communication between highway management system and human drivers. This project is conducting a pioneer research on the use of graphics on dynamic message signs. It can be linked with many other research project on ITS. Specifically, it is built upon previous research works carried out by the PIs in the study of textual VMS/DMS. The success of these studies, as evidenced by many publications and presentations resulted from the researches, will ensure the success of this project.
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, RIDOT, and TRB meetings. Besides printed reports, this information can also be packaged into CDs and be published through the world-wide-web. 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 DOTs are continuously looking to add new technologies and systems to help them better use the current facilities. The graphics-aided DMS messaging provides a natural and friendly interface between highway management system and human drivers and could greatly enhance the function of the intelligent transportation system. Graphical traffic information display on DMS, while being pioneered in several European countries, is new to US highway authorities. With the capability of today’s DMS systems, this project will identify effective means to leverage the graphical display capability to optimize DMS messaging display in terms of conspicuity, legibility, and comprehension. We anticipate this project to benefit highway management system, ITS researchers, and motorists as a whole, and help attain the mission of 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.
dynamic (variable) message sign, graphics (pictogram), graphics-aided message, driving simulation