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

1998 ◽  
Vol 1650 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Nicholas J. Garber ◽  
Srivatsan Srinivasan
Keyword(s):  
Threshold Value ◽  
Video Camera ◽  
Work Zone ◽  
Second Phase ◽  
Volume Data ◽  
Work Zones ◽  
Two Phase ◽  
Changeable Message Signs ◽  
Study Sites ◽  
Message Signs

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.

scholarly journals Improved Road Safety at Work Zones using Advanced Traveler Information Systems

2020 ◽  
Author(s):  
Mustafa Suhail Almallah ◽  
Qinaat Hussain ◽  
Wael K. M Alhajyaseen ◽  
Tom Brijs
Keyword(s):  
Traffic Safety ◽  
Driving Simulator ◽  
Work Zone ◽  
Speed Limit ◽  
Work Zones ◽  
Treatment Scenario ◽  
Lane Changing ◽  
Variable Message Signs ◽  
Study Results ◽  
Message Signs

Work zones are road sections where road construction or maintenance activities take place. These work zones usually have different alignment and furniture than the original road and thus temporary lower speeds are adopted at these locations. However, drivers usually face difficulty in adopting the new speed limit and maneuvering safely due to the change in alignment. Therefore, work zones are commonly considered as hazardous locations with higher crash rates and severities as reported in the literature. This study aims to investigate the effectiveness of a variable message signs (VMSs) based system for work zone advance warning area. The proposed system aims at enhancing driver adaptation of the reduced speed limit, encourage early lane changing maneuvers and improve the cooperative driving behavior in the pre-work zone road section. The study was conducted using a driving simulator at the College of Engineering of Qatar University. Seventy volunteers holding a valid Qatari passenger car driving license participated in this study. In the simulator experiment, we have two scenarios (control and treatment). The control scenario was designed based on the Qatar Work Zone Traffic Management Guide (QWZTMG), where the length of the advance warning area is 1000 m. Meanwhile, the treatment scenario contains six newly designed variable message signs where two of them were animation-based. The VMSs were placed at the same locations of the static signs in the control scenario. Both scenarios were tested for two situations. In the first situation, the participants were asked to drive on the left lane while in the second situation, they were instructed to drive on the second lane. The study results showed that the proposed system was effective in motivating drivers to reduce their traveling speed in advance. Compared to the control scenario, drivers’ mean speed was significantly 6.3 and 11.1 kph lower in the VMS scenario in the first and second situations, respectively. Furthermore, the VMS scenario encouraged early lane changing maneuvers. In the VMS scenario, drivers changed their lanes in advance by 150 m compared to the control scenario. In addition, the proposed system was effective in motivating drivers to keep larger headways with the frontal merging vehicle. Taking into account the results from this study, we recommend the proposed VMS based system as a potentially effective treatment to improve traffic safety at work zones.

Driver Understanding of Sequential Portable Changeable Message Signs in Work Zones

2007 ◽  
Vol 2015 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Brooke R. Ullman ◽  
Gerald L. Ullman ◽  
Conrad L. Dudek ◽  
Alicia A. Williams
Keyword(s):  
Work Zones ◽  
Changeable Message Signs ◽  
Driver Understanding ◽  
Message Signs

Evaluating Speed-Reduction Strategies for Highway Work Zones

2003 ◽  
Vol 1824 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Chunyan Wang ◽  
Karen K. Dixon ◽  
David Jared
Keyword(s):  
Traffic Control ◽  
Statistical Tests ◽  
Work Zones ◽  
Control Zone ◽  
Novelty Effect ◽  
Speed Reduction ◽  
Reduction Strategies ◽  
Changeable Message Signs ◽  
Message Signs ◽  
Over Time

Research was conducted to identify the potential of fluorescent orange sheeting, innovative message signs, and changeable message signs with radar for reducing speeds in highway work zones. The study investigated the effect of each strategy immediately after implementation (immediate effect) as well as several weeks after implementation (novelty effect). In addition to the overall effect of each strategy on all vehicles, the study included the effect on specific vehicle types during various lighting conditions. The researchers collected traffic data before, immediately after, and 2 or 3 weeks after implementation of each strategy (3 consecutive weeks for the changeable message sign). They collected data upstream of the temporary traffic-control zone, in the advancewarning area, and adjacent to the active work area. The researchers used various statistical tests to evaluate the significance of speed changes from phase to phase and adjusted vehicle speeds with the upstream speed changes over time. The study indicated that fluorescent orange sheeting and innovative message signs help reduce speeds at highway work zones (with diminished influence over time). Moreover, both strategies influence vehicle speeds more during the day than at night. Drivers of passenger vehicles tended to decrease their speeds more than did truck drivers. Changeable message signs with radar significantly reduced the vehicle speeds in the immediate vicinity of the sign and did not demonstrate a novelty effect.

scholarly journals Control Strategy Optimization for Two-Lane Highway Lane-Closure Work Zones

2019 ◽  
Vol 11 (17) ◽  
pp. 4567 ◽  
Author(s):  
Hua ◽  
Wang ◽  
Yu ◽  
Zhu ◽  
Wang
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Queue Length ◽  
Control Strategies ◽  
Good Alternative ◽  
Management Control ◽  
Work Zone ◽  
Delay Model ◽  
Work Zones ◽  
Two Phase

Traffic control is very important for two-lane highway lane-closure work zone traffic management. Control of the open lane’s right of way is very similar to that of a two-phase signalized intersection. Thus, four control strategies including flagger control, pre-timed control proposed by Schonfeld, pre-timed control proposed by Webster, and actuated control are employed for possible use at work zones. Two primary methodologies, the mathematical delay model adopted from signalized intersections, and the simulation model calibrated with field data, are proposed. The simulation and mathematical results show that control strategies for two one-way road intersections could be used for two-lane highway lane-closure work zones. Flagger control after gap-out distance optimization prevails over all the other control strategies in terms of stopped delay, queue length, and throughput, under low or high volumes. Actuated control could be a good alternative for work zone areas due to its small queue length and large vehicle throughput under moderate volume conditions. Our findings may help to optimize the work-zone control strategy and improve operational efficiency at two-lane highway lane-closure work zones.

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