Guidelines for Using Late Merge Traffic Control in Work Zones

2005 ◽  
Vol 1911 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Andrew G. Beacher ◽  
Michael D. Fontaine ◽  
Nicholas J. Garber
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Work Zone ◽  
Storage Space ◽  
Heavy Vehicles ◽  
Work Zones ◽  
Microscopic Traffic Simulation ◽  
Traffic Stream ◽  
Flow At Work ◽  
Full Factorial

The late merge traffic control strategy has been proposed as a way to improve flow at work zone lane closures by maximizing queue storage space and creating more orderly merging. The late merge instructs drivers to use all lanes to the work zone taper and then take turns proceeding through the work zone. There is little information available on when the late merge should be used, however, and a limited understanding of the factors that influence its performance. This paper discusses the results of a simulation study of the late merge concept using microscopic traffic simulation. The late merge concept was evaluated by comparing it with traditional traffic control, through a full factorial analysis. Results of the computer simulations showed that the late merge produced a statistically significant increase in throughput volume versus the traditional merge for the three-to-one lane closure configuration across all combinations of analysis factors. Although the two-to-one and three-to-two configurations did not show significant improvement in throughput overall, it was found that as the percentage of heavy vehicles increased, the late merge did foster higher throughput volumes than traditional traffic control. The results of the simulations indicate that the late merge may not provide as much of a benefit as previous studies had indicated and that the area of application for the late merge may be limited to situations where heavy vehicles constitute more than 20% of the traffic stream.

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.

Field Evaluation of Late Merge Traffic Control in Work Zones

2005 ◽  
Vol 1911 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Andrew G. Beacher ◽  
Michael D. Fontaine ◽  
Nicholas J. Garber
Keyword(s):  
Field Test ◽  
Traffic Control ◽  
Positive Response ◽  
Field Evaluation ◽  
Field Studies ◽  
Work Zone ◽  
Work Zones ◽  
Short Term ◽  
Term Field ◽  
Lane Closures

The traffic control strategy of the late merge in work zones was devised to improve flow and safety at work zone lane closures. Although some states have put the strategy into practice, only a handful of short-term field studies have formally evaluated its effectiveness. Additional field studies were necessary to assess the efficacy of the strategy and its proper deployment. This paper documents the results of a field test of the late merge traffic control conducted over several months. The late merge strategy was evaluated by comparing its effectiveness with that of traditional plans for work zone lane closures. The field test was conducted on a primary route in Tappahannock, Virginia, at a two-to-one lane closure. Results showed that throughput increased, but the increase was not statistically significant. Likewise, time in queue decreased, but the decrease was not statistically significant. These results were much less dramatic than those of other studies. Possible reasons for this disparity include different driver populations, road types, vehicle mixes, and site-specific characteristics. Despite limited improvements in throughput and time in queue, more drivers were in the closed lane, a positive response to the late merge signs.

Crash Testing and Evaluation of Work Zone Traffic Control Devices

1998 ◽  
Vol 1650 (1) ◽  
pp. 45-54 ◽  
Author(s):  
King K. Mak ◽  
Roger P. Bligh ◽  
Lewis R. Rhodes
Keyword(s):  
Traffic Control ◽  
Evaluation Criteria ◽  
Work Zone ◽  
Work Zones ◽  
Impact Performance ◽  
Crash Testing ◽  
Control Devices ◽  
Traffic Control Devices ◽  
Under Construction ◽  
The Impact

Safety of work zones is a major area of concern since it is not always possible to maintain a level of safety comparable to that of a normal highway not under construction. Proper traffic control is critical to the safety of work zones. However, traffic control devices themselves may pose a safety hazard when impacted by errant vehicles. The impact performance of many work zone traffic control devices is mostly unknown, and little, if any, crash testing has been conducted in accordance with guidelines set forth in NCHRP Report 350. The Texas Department of Transportation (TxDOT) has, in recent years, sponsored a number of studies at the Texas Transportation Institute to assess the impact performance of various work zone traffic control devices, including plastic drums and sign substrates, temporary and portable sign supports, plastic cones, vertical panels, and barricades. The results, findings, conclusions, and recommendations are presented for temporary and portable sign supports, plastic drums, sign substrates for use with plastic drums, traffic cones, and vertical panels, whereas those for barricades are covered elsewhere. Most of the work zone traffic control devices satisfactorily met the evaluation criteria set forth in NCHRP Report 350 and are recommended for field implementation. However, some of the devices failed to perform satisfactorily and are not recommended for field applications. The results from these studies are being incorporated into the TxDOT barricade and construction standard sheets for use in work zones.

scholarly journals Influence of Remotely Operated Stop–Slow Controls on Driver Behavior in Work Zones

2017 ◽  
Vol 2615 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Ashim Kumar Debnath ◽  
Ross Blackman ◽  
Narelle Haworth ◽  
Yusuf Adinegoro
Keyword(s):  
Traffic Control ◽  
Driver Behavior ◽  
Work Zone ◽  
Work Zones ◽  
Negative Effects ◽  
Traffic Lights ◽  
Increased Risk ◽  
Before And After ◽  
Driver Understanding ◽  
Rural Work

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.

Effect of Lane Width on Speeds of Cars and Heavy Vehicles in Work Zones

2005 ◽  
Vol 1920 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Madhav V. Chitturi ◽  
Rahim F. Benekohal
Keyword(s):  
Flow Speed ◽  
Heavy Vehicles ◽  
Work Zones ◽  
Passenger Cars ◽  
Highway Capacity ◽  
Speed Reduction ◽  
Interstate Highways ◽  
Highway Capacity Manual ◽  
Traffic Stream ◽  
Lane Width

Traffic data were collected from 11 work zones on Interstate highways in Illinois in which one of the two lanes was open. The reductions in free-flow speed (FFS) due to narrow lanes and lateral clearances in work zones were studied. It was found that the reductions in FFSs of vehicles in work zones because of narrow lanes were higher than the reductions given in the Highway Capacity Manual for basic freeway sections. The data also showed that the narrower the lane was, the greater the speed reduction was. The data showed that the FFSs of heavy vehicles were statistically lower than the FFSs of passenger cars, even though the speed limit was the same for both types of vehicles. In addition, the reduction in the FFSs of heavy vehicles was greater than the reduction in the FFSs of passenger cars. This greater reduction in the speed of heavy vehicles affected the performance of the traffic stream in work zones. Thus, it should be considered in the computation of the passenger car equivalence for heavy vehicles. It is recommended that 10, 7, 4.4, and 2.1 mph be used for speed reduction in work zones for lane widths of 10, 10.5, 11, and 11.5 ft, respectively.

scholarly journals Crash Testing and Analysis of Work-Zone Sign Supports

2002 ◽  
Vol 1797 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Karla A. Polivka ◽  
Ronald K. Faller ◽  
John R. Rohde ◽  
Dean L. Sicking
Keyword(s):  
Traffic Control ◽  
Work Zone ◽  
Work Zones ◽  
Design Elements ◽  
Impact Performance ◽  
Crash Testing ◽  
Control Devices ◽  
Traffic Control Devices ◽  
The Impact ◽  
Fundamental Design

A variety of traffic-controlling devices are used in work zones; some of these are not normally found on the roadside or in the traveled way outside of the work zones. These devices are used to enhance the safety of the work zones by controlling the traffic through these areas. Because of the placement of the traffic control devices, the devices themselves may be potentially hazardous to both workers and errant vehicles. The impact performance of many work-zone traffic control devices is mainly unknown, and to date limited crash testing has been conducted under the criteria of NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. The results of full-scale crash testing of flexible panel work-zone sign stands were evaluated and analyzed to quantify the features that successful devices shared, as well as common features of those devices that failed salient safety criteria. Parameters considered included sign base and upright properties, sign height, cross-member properties, and ancillary details. Results pointed to three problematic, fundamental design issues: ( a) combinations of base and upright stiffness and strength that generally lead to significant windshield damage, ( b) cross members that lead to windshield damage in the end-on (90°) impact orientation, and ( c) appurtenances that have an impact on performance. Although there are a significant number of variables that control the performance of a given device, these generalizations offer a basis for the evaluation of the fundamental design elements.

Microsimulation Analysis of Highway-Rail Grade Crossings: A Case Study in Lincoln, Nebraska

2008 ◽  
Author(s):  
Laurence R. Rilett ◽  
Justice Appiah
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Microscopic Traffic Simulation ◽  
Variable Message Signs ◽  
Driver Response ◽  
Grade Crossing ◽  
Grade Crossings ◽  
Message Signs ◽  
Different Levels

This paper examines the usefulness of supplementing railroad preemption operations at highway-rail grade crossings with variable message signs. Using the microscopic traffic simulation model, VISSIM, the effects on grade crossing operations of different train dwell times as well as different levels of driver response to a variable message sign in the vicinity of the crossing are assessed. The results affirm the potential usefulness of variable message signs for preventing lengthy queues and illustrate the importance of explicitly considering the delay experienced by vehicles on the blocked roadway in developing a traffic control strategy for highway-rail grade crossings.

Deploying and Integrating Smart Devices to Improve Work Zone Data for Work Zone Data Exchange

2021 ◽  
pp. 036119812110114
Author(s):  
Skylar Knickerbocker ◽  
Varsha Ravichandra-Mouli ◽  
Archana Venkatachalapathy
Keyword(s):  
Real World ◽  
Traffic Control ◽  
Data Exchange ◽  
Work Zone ◽  
Smart Devices ◽  
Work Zones ◽  
The Public ◽  
Additional Information ◽  
Starting Point ◽  
Linear Referencing System

Connected temporary traffic control devices (cTTCDs) that provide their location and status are a new tool that infrastructure owners and operators can begin to use to improve the accuracy of work zone data. By improving work zone data, better information can be provided to the public. Publishing these data through the WZDx (Work Zone Data Exchange) aims to improve safety by notifying drivers and vehicles of the location of verified work zones. Connected devices such as smart arrow boards and connected cones have continued to increase in number in the market, but little has been done to determine the best method of integrating these devices into a department of transportation’s (DOT’s) system. An approach is presented that integrates deployed smart arrow boards to indicate actual conditions as part of a planned work zone by leveraging a DOT’s linear referencing system. This method does not require any additional effort from field staff and improves the locational and temporal accuracy of work zone information as part of a WZDx. When fully deployed, this system showed that smart arrow boards could be automatically associated with a work zone in controlled test scenarios as well as in a limited sample under real-world conditions. In real-world conditions, contractors did not need to provide additional information to associate the smart arrow board with the 511 work zone event. This effort represents a starting point for how cTTCDs could be integrated into DOT systems to improve work zone data accuracy.

Crash Testing and Evaluation of Work Zone Barricades

1998 ◽  
Vol 1650 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Roger P. Bligh ◽  
King K. Mak ◽  
Lewis R. Rhodes
Keyword(s):  
Traffic Control ◽  
Work Zone ◽  
Department Of Transportation ◽  
Work Zones ◽  
Impact Performance ◽  
Crash Testing ◽  
Texas Department ◽  
Control Devices ◽  
Traffic Control Devices ◽  
The Impact

Proper traffic control and delineation are critical to achieving safety in work zones. However, the work zone traffic control devices themselves may pose a safety hazard to vehicle occupants or work crews when impacted by errant vehicles. Thus, there was a need to research the safety performance of work zone traffic control devices to ensure that they perform satisfactorily and meet NCHRP Report 350 guidelines. Several research studies sponsored by the Texas Department of Transportation evaluated the impact performance of various work zone traffic control devices, such as temporary and portable sign supports, plastic drums, sign substrates for use with plastic drums, traffic cones, and vertical panels. Specifically addressed are the studies on barricades. Standard wooden barricade construction was found to be unacceptable due to a demonstrated potential for intrusion of fractured members into the occupant compartment. In response to deficiencies identified in the wooden barricade tests, several alternate barricade designs were developed and successfully tested.

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