2013 Session: 625

• Evaluation of Temporary Ramp Metering for Work Zones
  Abstract: Ramp metering has been successfully implemented in many states to improve traffic operations on freeways. Studies have documented the positive mobility and safety benefits of ramp metering. However, there have been no studies on the use of ramp metering for work zones. This paper reports the results from the first deployment of temporary ramp meters in work zones in the United States. Temporary ramp meters were deployed at seven work zones in Missouri. Safety measures such as driver compliance, merging behavior, speed differentials, lane changing, and braking maneuvers were extracted from video-based field data. Mobility analysis was conducted using a calibrated simulation model and the total delays were obtained for under capacity, at capacity, and over capacity conditions. This evaluation suggests that temporary ramp meters should only be deployed at work zone locations where there is potential for congestion and turned on only during periods of high congestion. The compliance analysis showed that non-compliance could be a major safety issue in the deployment of temporary ramp meters. The use of a three-section instead of a traditional two-section signal head used for ramp metering produced significantly higher compliance rates. Mobility analysis revealed that ramp metering produces delay savings for high traffic volume work zones. For flows below capacity, ramp metering is not recommended since it increases total delays.
  Authors: Sun, Carlos; Edara, Praveen; Zhu, Zhongyuan
  Authors: Sun, Carlos; Edara, Praveen; Zhu, Zhongyuan
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2193
• Work Zone Lighting and Visual Performance: Analysis and Demonstration
  Abstract: In part because of the potential for high levels of glare from work zone illumination, recommendations for light levels from work zone illumination systems are substantially higher than levels used along roadways in non-work-zone locations. In a two part study, requirements for work zone illumination light levels were assessed. First, levels for workers varying in age from 20 to 60 years were evaluated using the relative visual performance model, with and without the presence of visibility-reducing glare. Except for the smallest, lowest-contrast tasks performed by the older age workers, an illuminance of 10 lx resulted in visibility well above the threshold even in the presence of glare, and an illuminance of 30 lx resulted in suprathreshold visibility for these conditions as well. The results of these computational analyses were largely confirmed in a full-scale, outdoor field demonstration attended by transportation agency engineers and highway contractors. Together, the findings suggest that when lighting systems provide sufficient glare control, light levels do not always need to be especially high to ensure adequate visibility by workers.
  Authors: Bullough, John D.; Besenecker, Ute; Snyder, Jeremy D.; Skinner, Nicholas P.
  Authors: Bullough, John D.; Besenecker, Ute; Snyder, Jeremy D.; Skinner, Nicholas P.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2244
• Field Evaluation of Automated Flagger Assistance Devices in Work Zones on Two-Lane Roads
  Abstract: Automated flagger assistance devices (AFADs) are designed to be remotely operated by a flagger positioned outside of the travel lane, thereby reducing their exposure to vehicular traffic. There are two types of AFADs. One type uses a remotely controlled stop/slow sign to alternately control the right-of-way. The other type uses remotely controlled red and yellow lenses and a gate arm to alternately control the right-of-way. While AFADs may increase the safety of flaggers, there were concerns that motorists may misunderstand AFADs; thus, increasing the potential for motorists to enter the lane closure under the stop condition. As part of a recent Texas Department of Transportation project, Texas Transportation Institute researchers conducted field studies at lane closures on two-lane, two-way roadways in Texas to assess the operational and safety effectiveness of AFADs relative to the use of flaggers. The research findings show that some motorists may misunderstand the directions provided by AFADs and enter the lane closure under the stop condition. The violation rate for the stop/slow AFAD without a gate arm was the highest and was significantly higher than the violation rate for the red/yellow lens AFAD (which requires a gate arm). Adding a gate arm to the stop/slow AFAD decreased the violation rate such that it was not significantly different from the red/yellow lens AFAD. In addition, alternative supplemental signs increased motorist understanding that the stop sign would change to a slow sign when motorists were allowed to proceed.
  Authors: Finley, Melisa Dayle
  Authors: Finley, Melisa Dayle
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-1209
  Practice-Ready: Yes
• Formalized Process for Work Zone Transportation Management Plan Performance Assessment in Virginia
  Abstract: The Federal Highway Administration’s Final Rule on Work Zone Safety and Mobility, which is part of the Code of Federal Regulations, requires Transportation Management Plans (TMPs) for all federally-funded roadway construction projects. These plans are a documented combination of traffic control, public relations, and transportation demand operations strategies designed to mitigate the impacts that work zones can have on safety and mobility. A key component in TMPs is monitoring and assessing of traffic impacts to incorporate lessons learned into future TMPs. The Virginia Department of Transportation (VDOT) sought to formalize a process to assess individual TMPs and TMPs at an agency-wide level. This paper summarizes the rationale and steps taken to develop this TMP assessment process. This process, which has been developed in the form of VDOT’s new TMP Performance Assessment Guidelines and Post-Construction Report Form, is outlined for various project complexities.
  Authors: Gallo, Anthony; Dougald, Lance Eric; Demetsky, Michael J.
  Authors: Gallo, Anthony; Dougald, Lance Eric; Demetsky, Michael J.
  Year: 2013
  Document Type: Paper
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-4544
  Practice-Ready: Yes
• Field Evaluation of Automated Flagger Assistance Devices in Work Zones on Two-Lane Roads
  Authors: Finley, Melisa
  Authors: Finley, Melisa
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-1209
• Evaluation of Temporary Ramp Metering for Work Zones
  Authors: Zhu, Zhongyuan
  Authors: Zhu, Zhongyuan
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2193
• Work Zone Lighting and Visual Performance: Analysis and Demonstration
  Authors: Bullough, John
  Authors: Bullough, John
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-2244
• Formalized Process for Work Zone Transportation Management Plan Performance Assessment in Virginia
  Authors: Dougald, Lance
  Authors: Dougald, Lance
  Year: 2013
  Document Type: Presentation
  Subject: Maintenance and Preservation; Operations and Traffic Management; Safety and Human Factors
  Session: 625
  Paper Number: 13-4544