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. - contains standards and principles for design, installation, and maintenance of traffic control devices in work zones
Key resources …
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

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)

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
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.

10. Number of Work Zone Fatalities - 2002

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.)

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. Why? worker/motor vehicle safety in temporary traffic control areas
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 termination areas of work zone
Use a series of channelizing devices and/or pavement markings
Observe after 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