Diversion from a Rural Work Zone with Traffic-Responsive Variable Message Signage System

Author(s):  
Alan J. Horowitz ◽  
Ian Weisser ◽  
Thomas Notbohm

An experiment was made to determine the degree of alternative-route selection from a rural freeway that occurs because of implementation of a traffic-responsive variable message signage system in a work zone. The message signs gave real-time estimates of travel time to the end of the work zone. Alternative-route selection was measured through extensive volume counts on the freeway and on parallel arterial streets, both before and after implementation of the signage system. In addition, traffic volumes were measured at a variety of locations where alternativeroute selection was likely to occur and where it was unlikely to occur. Analysis of peak period data found that alternative-route selection rates were between 7% and 10% of the freeway traffic, depending on the location and the day of the week.

Author(s):  
Ashim Kumar Debnath ◽  
Ross Blackman ◽  
Narelle Haworth ◽  
Yusuf Adinegoro

Remotely operated devices for traffic control—portable traffic lights and automated flagger assistance devices—are used to improve flagger safety in a one-lane-each-way work zone with lane closure. Previous research has measured the effectiveness of these devices as driver compliance rates and driver understanding of the devices, but the effects of these devices on driver behavior have not yet been examined comprehensively. Therefore, the influence of remotely operated stop–slow traffic control devices on driver behavior was examined. Video-recorded traffic movements from a rural work zone in the Queensland state of Australia provided driver speeds, deceleration profiles, stopping behavior, and compliance rates for a set of remotely operated devices new to Australia: static red–amber–green lights, static red–amber lights, static red–amber arrow lights, and mechanical stop–slow signs. Pneumatic tube traffic counters were used to collect driver speeds before and after the devices, and an on-road driver survey was conducted to elicit driver understanding of the devices. Results indicated that drivers had difficulty understanding the new devices, particularly the amber light and amber arrow options (which confused drivers about their meaning—to stop or to go). The new remotely operated devices resulted in higher approach speeds, greater variability in approach speeds, and faster deceleration rates than the flagger method. The good compliance rates observed with the remotely operated devices imply that the devices could improve flagger safety by reducing flagger exposure to traffic; however, the negative effects on driver behavior might indicate an increased risk of rear-end crashes in the advance warning area.


Author(s):  
Mustafa Suhail Almallah ◽  
Qinaat Hussain ◽  
Wael K. M Alhajyaseen ◽  
Tom Brijs

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.


2017 ◽  
Vol 10 (2) ◽  
pp. 270-278
Author(s):  
Adebayo Oladipo Owolabi ◽  
Olugbenga Joseph Oyedepo ◽  
Enobong Etim Okoko

Unsignalized intersections namely two-way stop-controlled intersection (TWSC) and all-way stop-controlled intersection (AWSC) are widely used in Akure. Five intersections consisting of three Tee and two Cross that were critical to traffic flow in the study area were selected for study. Data on geometric features were collected using odometer, while traffic parameters were captured and metered using cine camera placed at a vantage point from the road section during peak and off-peak periods on week days. Traffic flows at the intersections were expressed as functions of traffic characteristics and geometric features of the approaches; while the effect of distances of intersections before and after the intersections studied were also incorporated as a correction factors in the models. The models were developed using multiple linear regression technique with the aid of SPSS software and validated with empirical data other than those used for model calibration. Adjusted R2 values of 0.881 and 0.882 were obtained for Tee and Cross intersections respectively for peak period, while 0.938 and 0.940 respectively were obtained for the off-peak period. These indicate that the flow models are very robust in replicating the observed data. The predictive models have the potential to accurately estimate traffic flow at intersections in the study area and other cities of the world with similar traffic conditions.


2016 ◽  
Vol 29 (6) ◽  
pp. 1749-1761 ◽  
Author(s):  
Bojia Ye ◽  
Lance Sherry ◽  
Chun-Hung Chen ◽  
Yong Tian

Author(s):  
Priyanka Alluri ◽  
Albert Gan ◽  
Kirolos Haleem

Raised medians and two-way left-turn lanes (TWLTLs) are the two most common types of median treatments on arterial streets. This paper aims to conduct a detailed study on the safety impacts of conversion from TWLTLs to raised medians on state roads in Florida. In addition, the study also investigated several potential safety concerns related to raised medians on state roads, including crashes at median openings, vehicles directly hitting the median curb, and median crossover crashes. Based on data availability, 17.51 miles of urban arterial sections in Florida that were converted from TWLTLs to raised medians were analyzed. Police reports of all the crashes before and after median conversion were reviewed to correct miscoded crash types and obtain additional detailed crash information. Overall, a 28.5% reduction in total crash rate was observed after the 10 study locations were converted from TWLTLs to raised medians. The reductions in the proportions of left-turn and right-turn crashes were statistically significant, while the changes in the proportions of other crash types were not statistically significant. Furthermore, the crash data did not show evidence that raised medians are an additional hazard compared with TWLTLs.


Author(s):  
Alexander Skabardonis ◽  
Karl F. Petty ◽  
Robert L. Bertini ◽  
Pravin P. Varaiya ◽  
Hisham Noeimi ◽  
...  

The I-880 field experiment has produced one of the largest data bases on incidents and freeway traffic-flow characteristics ever compiled. Field data on incidents were collected through observations of probe-vehicle drivers before and after the implementation of freeway service patrols (FSPs) over a freeway section. Supplementary information was collected from the California Highway Patrol’s computer-aided dispatch system, FSPs, and tow-truck company logs. The incident patterns are described and the major factors affecting incident frequency and duration are identified. FSPs significantly reduced the response times but did not have a significant effect on the duration of all incidents.


Author(s):  
Jake Kononov ◽  
Zane Znamenacek

This paper examines risks associated with peak period lane closure during construction or maintenance work on urban freeways. In accordance with recently implemented policy by the Colorado Department of Transportation, lane closure would be allowed if reserve capacity were available. A relatively minor accident in the work zone caused substantial delays during the peak period that virtually paralyzed traffic in the Denver, Colorado, metropolitan area. This occurrence caused reexamination of the existing lane closure policy. Generally speaking, if a contractor is allowed greater flexibility in establishing work schedules, including the ability to work through peak periods, a lower bid can be expected. This paper compares savings in the cost of construction related to allowing lane closure during peak periods with the cost of potential incident-related delays in the framework of a quantitative risk analysis.


Author(s):  
Michael D. Fontaine

Work zone intelligent transportation systems (WZITSs) are promoted as a way to improve safety and reduce congestion at work zone locations where traditional traffic management centers do not exist. These systems usually integrate portable changeable message signs and speed sensors with a central control system that automatically determines appropriate messages that are based on current traffic conditions. Manufacturers of these systems claim that WZITSs can warn drivers of downstream congestion, alert drivers to slower speeds ahead, and suggest alternate routes on the basis of prevailing conditions. Transportation agencies are often asked to make decisions on the installation of a WZITS without the benefit of objective information on its expected performance. Relatively few operational tests of these systems have been performed, and the results are not always well documented or conclusive. Agencies need guidance to help them determine whether a WZITS system would improve safety and operations at a specific site. Applications of WZITSs are reviewed, and a series of guidelines for their deployment, based on lessons learned from past tests, is presented.


Author(s):  
Gerald L. Ullman ◽  
Paul J. Carlson ◽  
Nada D. Trout

Results of research conducted to investigate the short-term effects of the double-fine law in work zones implemented in Texas on January 1, 1998, are presented. Field studies of traffic speeds in several work zones were performed before and after the law was implemented. Traffic citation data for these same work zones were also obtained from the Texas Department of Public Safety. Analyses showed that traffic speeds in the work zones 4 to 6 months after the law was enacted were essentially unchanged from before the law was enacted. Similarly, citation frequency and fines levied were not significantly higher than they were before enactment of the law. The data suggested that a higher proportion of drivers who were issued citations after the law was implemented chose to take defensive driving training and to have the ticket subsequently dismissed. However, researchers could not determine whether this was due to the increased fine or to other external reasons.


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