Work Zone Traffic Control

1. Work Zone Traffic Control CE 453 Lecture 35

2. Objectives • Describe a maintenance of traffic plan for a roadway project • Define work zone problems and reasons for same • Identify work zone traffic control devices • Present details of work zone traffic control

3. http://mutcd.fhwa.dot.gov/ - contains standards and principles for design, installation, and maintenance of traffic control devices in work zones Key resources … http://wzsafety.tamu.edu/ AASHTO Roadside Design Guide: Chapter 9 discusses: Traffic Barriers, Traffic Control Devices and Other Features in Work Zones. Should be used with Traffic Control Devices Handbook – Part VI http://safety.fhwa.dot.gov/fourthlevel/pdf/bestprac.pdf

4. Maintenance of Traffic Plans • How/when traffic is maintained during construction • Typically required/not always – really needed • Include the following (if needed): • Diversion/detour alignments • Tapers and lane drops (see MUTCD) • Pedestrian accommodations • Traffic control (signals, sign type, sign location) http://www.fhwa.dot.gov/tfhrc/safety/pubs/89035/89035.pdf

5. Maintenance of Traffic Plans • Pavement marking, cones, barriers for channelization • Illumination and warning lights (steady for path, flashing for single points) • Policies for removal of signs, etc. • Staging of Traffic (how it flows) • Need for flaggers, etc. • Notes (e.g, move or sign all equipment when not in operation in the work zone) • No parking of employee cars in work zone

6. Maintenance of Traffic Plans • Cost estimate must include labor, signs, cones, etc. • Often not given proper time or attention – switching time most dangerous

7. Why are Work Zones more Prone to Crashes? • Why are work zones difficult for drivers and subsequently dangerous for workers? • Violate – Expectancy • Increased – Workload • Combine – Both

8. Work Zone Safety Facts • Late 90s … ~700 deaths/year … now, ~1000! • Tractor/trailer involvement in work zones crashes are high (26% of fatalities) • Work Zone crashes generally more severe (more injuries/fatalities than national average)- Fixed object impacts result in more injuries/fatalities than vehicle to vehicle impacts • ½ of work zone fixed object impacts occur at night (impact on staging??)

9. Work Zone Safety Facts • 1994-98 Average was that 16% of work zone fatalities were peds/bicyclists • Fatal work zone crashes are twice as high as non-work zone fatals on urban interstates (14% are FATAL!) • The majority of fatal work zone crashes occur on 55 mph or greater speed limits (No need for slow speed MOT? Ped/bike/ car fatalities? – increase over 35 mph but occur much lower) • 29% of fatals on weekends! (most in summer and fall) • ~150 workers killed each year (who are the workers???) Utility work in bike lanes can often be accomplished without blocking the entire lane. http://safety.fhwa.dot.gov/ped_bike/univcourse/swless12.htm

10. Number of Work Zone Fatalities - 2002

11. http://www.dot.state.ia.us/workzone/index.htm

13. Work Zone Traffic Control Devices • Cones/Tubular Markers • Vertical Panels • Drums (watch breakaway lamps – ballast at bottom and no greater than 25 kg) • Barricades Type I, II, and III • Shadow Trucks, etc. for moving construction or maintenance

14. Work Zone Traffic Control Devices • Temporary barriers (Portable Concrete Barrier (PCB) used by many states - uses: bridge widening, shielding roadside structures, roadway widening, and the separation of two-way traffic on a normally divided roadway) • Glare Screens (block view of construction, for design consider separation distance, vertical curvature, horizontal curvature) • Signs and Supports – meet normal specifications – breakaway within clear zone, etc. (MUTCD) • Warning lights (minimum height 3 ft. or 900 mm – securely fasten and battery on ground – why?)

15. Detour considerations • Speed • Capacity • Distance • Safety

16. How to increase detour capacity (e.g., during I-235 reconstructions – Univ. Ave., etc.) • eliminate some turns • reroute some trucks and buses • ban parking • ban loading/unloading during peak • eliminate some bus stops • coordinate signals • widen the traffic way • implement one-way • ITS??? (incident management, esp.)

17. http://www.dot.state.ia.us/design/e00_toc.htm#Chapter_9

19. Specifics for Work Zones • Fundamental principles of work zone traffic control design • Four work zone areas and their components • Taper lengths and types • Advance signing applications and factors that impact setup

20. Work Zone Traffic Control Design – 10 Fundamental Principles (MUTCD Part 6) Why? worker/motor vehicle safety in temporary traffic control areas • Traffic safety must be integral and high-priority during project development (from planning to construction) and rehab/ maintenance or utility activities • Follow same principles of normal permanent roadside/roadway designs (goal is use comparable geometrics/traffic control if possible)

21. Fundamental Principles (cont.) • Produce a traffic control plan (TCP) (understand before field work) • Traffic should be inhibited as little as practicable • Avoid frequent and abrupt geometry changes • Provide for incident management vehicles • Minimize work time and do off-peak if possible • Guide drivers/peds in a clear and positive manner approaching and through zone (adequate traffic control, proper action with permanent control, flagging)

22. Fundamental Principles (cont.) • Routinely inspect your traffic control elements • Maintain the roadside during construction (for safety) • Train all levels of workers in temporary traffic control zone safety • Provide statutes that allow work zone traffic control (no real engineer control???) • Maintain good public relations (media)

23. Activity Area Storage (not shown) 4. Termination Area – returns traffic to normal Work 3. Activity Area – where the work happens Buffer 2. Transition Area – channels the traffic Traffic 1. Advance Warning - what to expect

24. Older AASHTO New MUTCD

25. Tapers – Important Safety Element of Work Zones (Why?) • Used in transition and possibly terminationareas of work zone • Use a series of channelizing devices and/or pavement markings • Observeafter implementation (adjust as appropriate) • Channelizing device spacing (in feet) approximately equal to the roadway speed in MPH

26. Taper Lengths (See Table next page) • 40 mph or less L = WS2/60 • 45 mph or greater L = WS L = taper length in feet W = width of offset in feet S = Posted speed, off-peak 85th percentile speed before work, or anticipated operating speed in MPH

28. Taper Types • Merging – longest because it requires drivers to merge with other traffic (use L minimum) • Shifting – merging not required, but a lateral shift is (use ½ L minimum) • Shoulder – used where shoulder may be mistaken for driving lane (use 1/3 minimum, but L is traveled on) • Downstream – provide visual cue that original lane is now accessible (optional – if used 100 feet/lane minimum, 20-foot device spacing) • One-lane, Two-way – used when one lane closed and used by both directions (use 100-foot maximum and typ. flagger)

30. Warning Signing for Typical Applications • Place warning signs in advance of work areas at spacing indicated • Distances measured from transition or point of restriction start • Table 6C-1 suggests spacing for warning signs on different roadway types • “A” is distance from transition/point of restriction to first sign • “B” is distance to from first to second sign, and • “C” is distance from second sign to initial sign encountered by driver (in a three-sign series)

32. Selecting a Typical Sign Setup Consider: • Duration of Work (long-term stationary, intermediate-term stationary, short-term stationary, short duration, and mobile) • Location of Work (e.g., outside shoulder, near/on shoulder, median, on roadway) • Roadway Type (e.g., rural two-lane, urban arterials, other urban arterials, rural or urban divided/undivided, intersections, and freeways) • MUTCD has 44 typical applications split by these categories

38. I65 Work Zone, North of Louisville