Stated Preference Analysis of Driver Route Choice Reaction To Variable Message Sign Information

Highway Authorities in many parts of the world have, for some years, been using variable message panels mounted above or beside the camageway to communicate short messages to motorists. Most such applications have been concerned with hazard warning and speed advice. However, their use to deliberately affect route choice is an area of great current interest. It is recognised that they have a potential role in managing demand to match the capacity available, not only to alleviate acute problems caused by roadworks and accidents, but also to contribute to satisfactory performance of networks operating close to capacity over extended periods of high, but variable, demand. The installation and operation of the panels is not cheap and there is a widespread belief that overuse, or inappropriate use, of the messages may lead to them losing their credibility with the motorists and thus ceasing to be effective. It is therefore very important to understand the likely response of motorists to various messages before displaying them and even before selecting sites for the installation of panels. A number of researchers have explored drivers' responses to traffic information and route advice offered via variable message signs (VMS). Evidence from traffic counts suggests that messages can persuade somewhere between 5% and 80% of drivers to divert. Clearly this range of estimates is far too wide to support the use of VMS for fine tuning the pattern of demand. A major contributor to the uncertainty, however, is the varying, and often unknown, proportion of drivers whose destination makes the message relevant to them. More detailed studies involving driver interviews downstream of the VM!3 site to determine the relevance of the message, as well as the response to it, include those by Kawashima (1991) and Durand-Raucher et al. (1993). These studies have produced more precise estimates of compliance but the results are obviously limited to those messages which were on display at the time the interviews were being conducted. A number of researchers have sought to overcome this restriction by examining response to a range of messages presented via a stated preference exercise (see for example Hato et al., 1995; Shao et al., 1995 and Bonsall and Whelm, 1995), via a route-choice-simulator (see for example Firmin, 1996; Bonsall and Merrall, 1995 ; Bonsall and Palmer, 1997) or via a full scale driving simulator or system mock-up (see for example Mast and Ballas, 1976 and Brocken and Van der Vlist, 1991). This research has suggested that response is highly dependent on message content, subjects' network knowledge, and on the extent of any implied diversion. We see particular value in extending this earlier work to consider a wider range of messages and to determine whether the route-choice-simulator results can be repeated and extended using a somewhat cheaper methodology - namely stated preference analysis. The objectives of the work reported in this paper were thus: to extend to our existing database on drivers' response to traffic information and route advice provided in variable message signs, to include a wider range of messages. to construct explanatory models of drivers' route choice behaviour in response to a variety of messages to explore the factors influencing this response to compare these results with previous results obtained using a variety of data collection methods to draw policy conclusions, where appropriate, on the use of variable message signs to influence drivers' route choice to draw conclusions, where appropriate, on our data collection and modelling methodology

A driving simulator study to evaluate the impact of portable changeable message signs (PCMS) on driver speed characteristics

This research project examined the effects of sequential Portable Changeable Message Signs (PCMS) on driver behavior in work zones. PCMS are temporary traffic control (TTC) devices, part of Intelligent Transportation Systems, which supplement static signs to provide advance warning and real-time information to drivers. Text and number based messages are displayed on the PCMS for which detailed evaluation has not been carried out before. This research fills this gap using a driving simulator (DS) supplemented by objective and subjective surveys. A work zone on I-44 in rural Missouri was replicated in the DS using video recordings and GIS (Geographical Information System) data. The DS experiment consisted of five scenarios (0-4). The control scenario (scenario-0) was compared to scenarios 1-4. In the DS, evaluation of the four message signs displayed on the PCMS used by the Missouri Department of Transportation (MoDOT) and their effects on drivers\u27 speed was carried out. The results from the experiment showed significant decrease in speed of driver as a result of the type of messages displayed by the PCMS. From the objective analysis results, message sign-4 (MS-4) saw the maximum decrease in the speeds of drivers when compared to the control scenario. The subjective (survey) results showed that MS-2 was the most preferred message as it displayed a specific speed limit for the participants to follow. Also, the 85th percentile speeds before the construction zone closely matched with the displayed speed for MS-2. The results obtained from the subjective survey reinforced the fact that PCMS were effective in reducing the speed of the drivers --Abstract, page iii

Information & communication technologies - panacea for traffic congestion?

As road pricing, telematics and logistics evolve, information and communication technologies (ICT) aim directly at making traffic flow more efficiently in a given infrastructure. Furthermore, the virtual world gives rise to new business fields and decentralised structures which affect the development of transport indirectly. While technological progress continues to drive qualitative improvements in traffic conditions, e-business and telework in particular have, for structural reasons, a much less pronounced effect on traffic than widely presumed. ICT helps in organising traffic flows more efficiently and plays a supplementary role as transport-relevant instrument, but it is not a panacea for traffic congestion.traffic, autobahn, ICT, LBS, mobile telephony

Journey decision making: the influence on drivers of dynamic information presented on variable message signs

In many highways environments electronic media such as variable message signs are increasingly being used to provide drivers with up-to-date dynamic information in order to influence driving decision making during journeys. These decisions may be associated with strategic choices, such as route selection, or tactical decisions, such as driving at a certain speed, or altering driving style. This paper presents a study that used two methods - a scenario approach and a medium-fidelity driving simulator. Data from both methods are presented here and include decision making and driving performance data. These data provide an insight into the role of information and other contextual influences in decision making in the driving context specifically, but also has useful implications for the way in which information should be designed in other decision making contexts, such as travel using public transport, or supporting real-time complex control operations. The use of multiple data collection approaches also enabled data comparisons to be made, thus improving overall confidence in conclusions. The paper highlights the role of familiarity with information wording and context, level of detail, interpreted meaning, previous experience and contextual cues on trust in information and consequently behaviour in response to the information presented

Visual Perception and Understanding of Variable Message Signs: The Influence of the Drivers’ Age and Message Layout

Variable message signs (VMS) are used to display messages providing up‐to‐date traffic‐ relevant information so that drivers can safely adapt their behavior in real time. The information reported in a VMS should be brief but comprehensive to minimize perception time. The latter can be influenced by the way the message is displayed. This study investigates how the different ways of displaying the same message can influence reading time and the information perception process at different driving speeds. Specifically, the following message characteristics are investigated: (i) use of uppercase and lowercase letters; (ii) use of familiar pictograms; and (iii) use of less familiar pictograms. Furthermore, as perception time typically changes with ageing, drivers belonging to three different age classes are tested. The experimentation was performed by simulating a vehicle passing along a straight road upon which a VMS displaying different messages was placed. Exper‐ imentation results are analyzed using the Kruskal–Wallis test, Friedman rank‐sum test and Welch one‐way ANOVA, showing that: (i) the use of uppercase or lowercase does not seem to significantly affect reading times; (ii) the use of pictograms that are not very familiar to habitual road‐users can be counterproductive for the perception process; (iii) elderly drivers always have greater difficulty in perceiving the message than young or middle‐aged drivers. The findings of this study can be of help for traffic authorities to design the most suitable structure for a VMS so that its information can be unequivocally and immediately conveyed to drivers

IMPACT OF DYNAMIC MESSAGE SIGNS ON OCCURRENCE OF ROAD ACCIDENTS

Dynamic Message Signs (DMS) are key components of Advanced Traveler Information Systems to manage transportation networks, reduce congestion and improve safety through providing motorists with real-time information regarding downstream traffic conditions. While DMSs are intended to improve efficiency and safety of road networks, little has been done to study the effect of the signs on driver safety and their localized safety impacts. This thesis employs ground truth data as the basis to investigate the issue in State of Maryland in a four-year period (2007-2010). The results show no significant difference between the accident pattern in the proximity of DMSs and the onward adjacent segments. On-and-off study is also conducted on DMS operation status (on/off). The results converge with the previous analysis suggesting that there is no meaningful relationship between occurrence of accidents and presence of DMSs. Besides, statistical analysis on DMS characteristics and accidents in impact areas are performed

Tribal Corridor Management Planning: Model, Case Study, and Guide for Caltrans District 1, Research Report 10-01

In Northern California, tribal governments and personnel of the California Department of Transportation (Caltrans) District 1, have applied innovative context-sensitive solutions to meet a variety of transportation challenges along state highways that traverse tribal lands. This report describes and discusses the efforts under way and offer suggestions for continuing and extending these initiatives through the development of Tribal Corridor Management Plans (TCMPs). The methods employed in this project are multidisciplinary and include: (1) content analysis of existing corridor management plans; (2) literature review to identify “best practices;” (3) participant observation; (4) interviews with local stakeholders; (5) focus group interviews with Caltrans personnel; and (6) landscape analysis. This study’s authors conclude that Caltrans District 1 staff and tribal governments share common goals for highway operations; however, progress —while significant—has been somewhat hampered by geographic and administrative challenges. It is recommended that Caltrans and the tribes seek early and frequent communication and collaboration to overcome these obstacles. Further, they identify several examples of non-standard design elements that could be incorporated into highway improvements to enhance local sense of place among both residents and travelers. A preliminary TCMP for the segment of State Route 96 that lies within the boundaries of the Hoopa Valley Indian Reservation is presented as an example. Beyond its role as a guide for initiating tribal corridor projects within Caltrans District 1, the report should prove instructive for any efforts to enhance sense of place within transportation byways, particularly in Native communities