Work Zone Mobility and Safety Program
Photo collage: temporary lane closure, road marking installation, cone with mounted warning light, and drum separated work zones.
Office of Operations 21st Century Operations Using 21st Century Technologies

Designing for Speed, Congestion, and Delay in the Work Zone (PowerPoint Presentation)

Slide 1. Designing for Speed, Congestion, and Delay in the Work Zone

Gerald Ullman
Research Engineer
Transportation Operations Group
Texas Transportation Institute

Texas Transportation Institute logo

Slide 2. Work Zone Safety Trends

Graph of work zone fatalities of 600 to 1,400 per year  for 1996 to 2003: 700 in 1996,  650 in 1997, 790 in 1998, 900 in 1999, 1,050 in 2000, 1,000 in 2001, 1,200 in 2002, and 1,050 in 2003.

Slide 3. Work Zone Safety Trends Pie Chart

no work zone influence=71%, work zone indirectly involved=19%, work zone conditions directly involved=6%, during work zone setup/removal=4%

Slide 4. Work Zone Consequences

  • Approximately 40,000 injuries/year nationally
  • Approximately 120 workers killed annually
  • Approximately $4.5 billion/year national economic cost

photo of roadway warning sign stating "slow down or die"

Slide 5. 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

Cartoon of a flagger holding a sign stating "Road work next 15,000 miles."

Slide 6. Work Zone Exposure

Slide 6

Slide 7. The Result…

Beetle Bailey cartoon. The first panel shows General Halftrack riding in a car and saying into a cell phone "Hello, Bureau of Missing Persons?" The second panel shows his car in a traffic jam stretching over hills and into the distance. Channelizing cones and work zone signs stating "Slow" and "Slow, work area" are on both sides of the roadway. His speech balloon shows "I'd like to report a missing road repair crew."

Real Life Adventures cartoon showing a road sign stating "2 left lanes closed for no reason whatsoever next 21 miles."

Slide 8. Speed Management in Work Zones

  • Enforcement
  • Speed control technologies

Slide 9. Enforcement considerations

  • Realistic and "reasonable" speed limits
  • Adequate coordination between DOT and enforcement agencies
  • Labor availability

photo of signs next to roadway stating "work zone, traffic fines double" photo of police officer ticketing a driver

Slide 10. Enforcement

  • Circulating: 2–3 mph lower
  • Stationary: 3–13 mph lower
  • Police Traffic Controllers: 2–14 mph lower
  • Operation Hardhat: ???

photo of police car parked next to roadway photo of workers on a road maintenance machine aiming a radar gun

Slide 11. Work Zone Speed Control Technologies

  • Enforcement surrogates
  • Driver information/feedback
  • Perceptual methods

Slide 12. Enforcement Surrogates

  • "Dummy" vehicles: –
  • Unmanned radar: 0–2 mph lower
  • Remote enforcement: –
  • Automated enforcement: –

photo of a traffic camera above a roadway computer screen showing photo of a car's rear license plate

Slide 13. Driver Information/Feedback

  • Changeable Message Signs (CMS): 0–2 mph lower
  • CMS with radar: 0–6 mph lower
  • Speed trailers: 2–10 mph lower
  • CB Wizard: 0–2 mph lower
  • Variable Speed Limits: 0–5 mph lower

night photo of portable message board showing speed of approaching traffic photo of portable message board showing speed of approaching traffic photo of portable message board showing speed of approaching traffic as 66 mph

photo of portable message board showing speed of approaching traffic as 35 mph

Slide 14. Perceptual Methods

  • Rumble strips: 1–6 mph lower
  • Transverse markings: 0 mph
  • Narrowed lanes: 0–8 mph lower

photo of a roadway narrowed with moveable barriers on each side

photo of rumble strips across a lane

Slide 15. 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

Slide 16. "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: money

Slide 17. Increasing Capacity

  • Late-merge or dynamic merge control
  • Moveable barrier systems
  • Contractor accountability

Slide 18. Late Merge

Slide 18

Slide 19. Moveable barrier

photo of a moveable barrier transfer machine photo of a moveable barrier transfer machine

Slide 20. Contractor Accountability

  • Arizona SR 68 (FHWA-HOP-04-032)
  • $400k incentive pool
  • Travel times exceeding 27 minutes reduced incentive pool

photo of Arizona State Route 68 photo of traffic camera and lights next to highway

Slide 21. Reducing Traffic Demands

  • Working at night and weekends
  • Full roadway closures
  • Portable Intelligent Transportation System (ITS) technology

Slide 22. Extent of Nightwork

Slide 22

Slide 23. Concerns about Nightwork

  • Efficiency, quality of work
  • Safety
    • Traveling public
    • Workers
  • Worker quality of life

Slide 24. 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

Slide 25. A Broader Perspective

map of Katy, Texas, showing a section of Katy Freeway circled within a larger circle superimposed on the city

Slide 26. ITS Applications in Work Zones

photo of moveable message board screen shot of web site for Lake Springfield Bridge message boards and traffic conditions

Slide 27. Key principles

  • Motorists should not be told something they already know
  • Motorists should never be provided incorrect information (must maintain credibility)
  • Motorist diversion thresholds: 10–20 minutes delay

Slide 28. Questions


Slide 29. Transportation Management Plan

  • Temporary Traffic Control (TTC) Plan
  • Transportation Management Considerations
  • Public Information Considerations

photo of warning sign stating "lane drop ahead" next to unfinished highway bridge construction

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