Enhancing the Messages Displayed on Dynamic Message Signs

Abstract

Summary: A human factors study was carried out to help enhance ways to communicate with highway motorists through dynamic message signs (DMS). Overhead mounted DMSs have been increasingly used by highway authorities in the United States to present real-time traffic information and travel advice to motorists. It is critical to post sign messages that can be quickly and clearly understood by motorists, especially in high-volume traffic and construction/repair zones. Properly worded and formatted sign messages could spell the difference between comprehension and confusion. Message display factors investigated in the study include display effects, color schemes, wording, and formats. Two approaches were employed in this study. First, a questionnaire survey was developed to collect motorists' preferences regarding various message display factors. Second, a series of lab driving simulation experiments were set up to assess the effects of these factors and their interactions on motorists' comprehension of DMS messages. Study results suggested that static, one-framed messages with more specific wording and no abbreviations were preferred. Amber or green or a green-amber combination were the most favored colors. Younger subjects took less response time to the DMS stimuli with higher accuracy than older subjects. There were no significant gender differences.

Analyzing drivers’ preferences and choices for the content and format of variable message signs (VMS)

“…In order to identify the subjective attitude and preference of drivers for VMS formats, Yang et al (2005) concluded that most subjects preferred the green and amber color combination. Moreover, if only one color was used, red was found to be the least preferred option.…”

“…This includes: (i) revealed preference (RP) questionnaire surveys (Chatterjee et al, 2002;Kilpeläinen and Summala. 2007;Wang et al, 2009;Hassan and Abdel-Aty, 2011), stated preference (SP) questionnaire survey (Benson, 1996;Emmerink et al, 1996;Wardman et al, 1997;Al-Madani andAl-Janahi, 2002a, 2002b;Hassan and Abdel-Aty, 2011;Gan and Ye, 2011;Jindahra and Choocharukul, 2013;Spyropoulou and Antoniou, 2014;Ronchi et al, 2016) and a combination of SP and RP survey (Al-Deek et al, 2012), (ii) driving simulators (Mahmassani and Chen, 1991;Wang and Cao, 2005;Lai, 2008Lai, , 2012Shinar and Vogelzang, 2013;Williams et al, 2015;Sharples, et al, 2016;Roca et al, 2018 ), and (iii) the combination of questionnaire survey and driving simulators (Yang et al, 2005;Wang et al, 2007;Lai, 2010;Cristea and Delhomme, 2014;Zhong et al, 2016).…”

“…The former is mainly focused on identifying what kinds of VMS contents and formats satisfy drivers' requirements, while the latter mainly measures which one has the minimum distraction time when drivers receive the information. Based on the objective approach, considerable research efforts have been made to identify the optimum VMS content and format using, for example, response accuracy (Richards, et al,2004;Wang and Cao,2005;Lai, 2008Lai, , 2010Lai, ,2012Shinar and Vogelzang, 2013;Roca et al, 2018), response duration (Wang and Cao,2005;Yang et al,2005;Wang et al, 2007;Lai, 2008Lai, , 2010Lai, , 2012Shinar and Vogelzang, 2013;Roca et al, 2018), response distant (Williams et al, 2015;Roca et al, 2018) and gaze number (Roca et al, 2018). However, there is a dearth of research on the subjective measure to determine whether the displayed content and format of VMS is preferable to motorists.…”

The Effect of Design and Placement of Work-Zone Warning Signs on Driver Speed Compliance: A Simulator-Based Study

“…On the other hand, reading time for DMSs is higher than for traditional static signs because motorists see static signs regularly, and drivers may rely on memory more than actually reading the sign to obtain the message (Wang & Cao, 2005;Yang et al, 2005). A message presented by a static sign is consistent, whereas the message conveyed by a DMS may change based on a number of factors, requiring driver attention with each encounter (Dudek, 2004).…”

“…There is also a wealth of literature that describes the appropriate frame scheme, color combinations, and wording to increase the readability of DMS among drivers (e.g., Yang et al, 2005). Other key design parameters include the type of display technology (lightemitting, light-reflecting, etc.…”