Transportation Operations Group Designing for Speed, Congestion, and Delay in the Work Zone Gerald Ullman Research Engineer Texas Transportation Institute
Transportation Operations Group Work Zone Safety Trends
Transportation Operations Group Work Zone Consequences 40,000 injuries/year nationally 120 workers killed annually $4.5 billion/year national economic cost
Transportation Operations Group Some other facts… 43,500 miles of the National Highway System sees at least one day of work zone activity annually In summer, we lose the equivalent of 41 million vehicles per day of roadway capacity due to work zones
Transportation Operations Group Work Zone Exposure
Transportation Operations Group The Result…
Transportation Operations Group Speed Management in Work Zones Enforcement Speed control technologies
Transportation Operations Group Enforcement considerations Realistic and “reasonable” speed limits Adequate coordination between DOT and enforcement agencies Labor availability
Transportation Operations Group Enforcement Circulating2-3 mph Stationary3-13 mph Police Traffic Controllers2-14 mph Operation Hardhat???
Transportation Operations Group Work Zone Speed Control Technologies Enforcement surrogates Driver information/feedback Perceptual methods
Transportation Operations Group Enforcement Surrogates “Dummy” vehicles Unmanned radar0-2 mph Remote enforcement Automated enforcement -----
Transportation Operations Group Driver Information/Feedback Changeable Message Signs (CMS)0-2 mph CMS w/ radar0-6 mph Speed trailers2-10 mph CB Wizard0-2 mph Variable Speed Limits0-5 mph *
Transportation Operations Group Perceptual Methods Rumble strips1-6 mph Transverse markings0 mph Narrowed lanes0-8 mph
Transportation Operations Group Congestion and Delay Management in Work Zones Increase work zone capacity and efficiency of flow Reduce traffic demands at work zone bottleneck points Communicate accurate estimates of delay and congestion expectations
Transportation Operations Group “Get In, Get Out, Stay Out” 77% motorists prefer long-term repairs, even if delays are more significant Focus on longer-lasting materials, better construction methods, longer service life horizon Major constraint: $$
Transportation Operations Group Increasing Capacity Late-merge or dynamic merge control Moveable barrier systems Contractor accountability
Transportation Operations Group Late Merge
Transportation Operations Group Moveable barrier
Transportation Operations Group Contractor Accountability Arizona SR 68 (FHWA-HOP ) $400k incentive pool Travel times exceeding 27 minutes reduced incentive pool
Transportation Operations Group Reducing Traffic Demands Working at night and weekends Full roadway closures Portable Intelligent Transportation System (ITS) technology
Transportation Operations Group Extent of Nightwork
Transportation Operations Group Concerns about Nightwork Efficiency, quality of work Safety Traveling public Workers Worker quality of life
Transportation Operations Group Full Roadway Closures Roadway completely closed, traffic routed to alternative routes Increases work efficiency Eliminates traffic/work crew conflicts Requires high degree of coordination and contingency planning Impacts off-site difficult to predict and assess
Transportation Operations Group A Broader Perspective
Transportation Operations Group ITS Applications in Work Zones
Transportation Operations Group Key principles Motorists should not be told something they already know Motorists should never be provided incorrect information (must maintain credibility) Motorist diversion thresholds: minutes delay
Transportation Operations Group Questions
Transportation Operations Group Transportation Management Plan Temporary Traffic Control (TTC) Plan Transportation Management Considerations Public Information Considerations