Influence of Exposure Duration on the Effectiveness of Changeable-Message Signs in Controlling Vehicle Speeds at Work Zones

Abstract

In work zones, drivers do not slow down in response to conventional signs. Changeable-message signs (CMSs) equipped with a radar unit can be used to display specific warning messages to speeding drivers. The radar unit detects the speed of each vehicle entering the work zone and can be programmed to activate the CMS if the speed of the vehicle exceeds a preset threshold value. A two-phase longitudinal study was conducted. The first phase, conducted by Garber and Patel, examined the short-term effectiveness of the CMS with radar in reducing vehicle speeds in work zones. The second phase, some of the results of which are presented, evaluated the influence of the duration of exposure of the CMS with radar on its effectiveness in reducing speeds in work zones. Speed and volume data for the population were collected at the study sites by automatic traffic counters placed at the beginning, middle, and end of each work zone. In addition, the speeds of individual drivers who triggered the CMS by exceeding the threshold speed were also recorded (using a video camera) at two other locations within the work zone for several weeks and analyzed. The results of the study indicated that the duration of exposure of the CMS does not have a significant impact on speed characteristics and driver behavior. Therefore, the CMS continues to be effective in controlling speeds in work zones for projects of long duration. The results also indicated that the CMS with radar reduces the probability of speeding at work zones and that this effect is maintained for at least up to 7 weeks.

Women in the U.S. construction industry: An analysis of fatal occupational injury experience, 1980 to 1992

“…Use of changeable message signs (CMS) with radar units on interstate highways in Virginia have been shown to be significantly FIGURE 2. Frequency (%) and rates (per 100,000 workers) of fatalities by age group among U.S. female construction workers, 1980-1992. effective in altering driver behavior in construction work zones [Garber and Patel, 1994]. CMSs were observed to result in lower speed variance and reduction of vehicles speeding by 50% or more [Garber and Patel, 1994].…”

“…Frequency (%) and rates (per 100,000 workers) of fatalities by age group among U.S. female construction workers, 1980-1992. effective in altering driver behavior in construction work zones [Garber and Patel, 1994]. CMSs were observed to result in lower speed variance and reduction of vehicles speeding by 50% or more [Garber and Patel, 1994]. Richards et al [1985] have shown that flagging could reduce work zone speeds by an average of 19%, but noted the importance of specially trained personnel.…”

“…NTOF data do not allow determination of cases in work zones. Factors suggested in previous studies and reports to be associated with motor vehicle fatalities among construction workers in highway construction work zones include: lack of audible signals or backup alarms to warn workers of impending collisions; insufficient warning signs for drivers; lack of training in traffic control for flaggers [Koran, 1992]; inefficient protection devices for workers once a vehicle has penetrated work area barriers [Anderson, 1989]; excessive vehicle speeds in construction work zones [Pigman and Agent, 1990;Garber and Patel, 1994;Sorock et al, 1996]; large speed differential among vehicles [Paulsen et al, 1978]; inappropriate use of traffic control devices; inadequate work zone layout; and poor understanding of construction and maintenance work zone hazards [Pigman and Agent, 1990]. Various measures for reducing pedestrian and occupant fatalities among construction workers have been reviewed [Ore and Fosbroke, 1997].…”

Factors Influencing Behavior in a Boating Speed Zone

“…Explaining compliance is not easy, as is evidenced by the related literature on compliance in roadway construction zones, which lack silver-bullet solutions that do not involve the presence of law enforcement (e.g., Garber and Srinivasan, 1998;Ullman et al, 1999;Maze et al, 2000). Additionally, although some research on wildlife-vehicle collisions examines attempts to modify human behavior (Messmer et al, 2000;Gordon et al, 2001;Al-Ghamdi and AlGadhi, 2004), the literature has a much stronger emphasis on spatial separation (e.g., Clevenger and Waltho, 2000;Romin and Bissonette, 1996;Farrell et al, 2002).…”

Determining the drivers’ acceptance of EFTCD in highway work zones

“…For example, a number of studies (Garber and Patel, 1994;Garber and Srinivasan, 1998;Brewer et al, 2006;Bai et al, 2010) revealed that a changeable message sign was more effective than traditional traffic control devices in reducing the number of speeding vehicles in work zones. Another evaluation showed that changeable message signs with radar effectively reduced vehicle speeds in the immediate vicinity of the sign (Dixon and Wang, 2002).…”