PROBLEM IDENTIFICATION AND CORRECTION BY LOCATION OF PROBLEM
LOCATION		POSSIBLE PROBLEM	POSSIBLE TRAFFIC CONTROL CHANGE
1	Accidents or incidents occurring in the warning or approach area of the work zone	Insufficient advance warning signs	· Add warning signs · Increase size of advance warning signs · Use changeable message signs
		Speeds too high or high variance in speeds	· Add advisory speed signs · Provide extra enforcement · Install rumble strips
		Improper flagging technique	· Train flaggers · Move flaggers upstream
		Insufficient work zone traffic capacity	· Provide alternate routes · Change work schedule to exclude peak traffic periods
		Signs not visible at night	·Mount signs at correct height above roadway · Install flashing warning lights on signs · Replace signs not meeting visibility requirements · Illuminate signs
		Improper lane changes	· Lengthen taper · Move taper position upstream
2	Accidents or incidents occurring in the transition  area of the work zone	Insufficient advance warning	· Add advance warning signs · Increase size of advance warning signs · Use variable message sign
		Lack of sufficient sight distance to taper	· Move taper upstream to increase sight distance
		Improper merging at lane closures	· Move taper upstream to increase sight distance · Lengthen taper
		Insufficient work zone capacity	· Provide alternate routes · Change work schedule to exclude peak traffic periods
		Transition not visible at night	· Illuminate or reflectorize channeling devices · Add temporary pavement markers
		Speeds too high or high variance in speeds	· Provide extra enforcement · Add advisory speed signs
		Advance warning signs too far upstream from transition	· Move warning signs more frequently
3	Accidents or incidents occurring on curves	Inadequate design for prevailing vehicle speeds	· Improve edge line delineation · Add advisory speed plates
4	Accidents or incidents occurring in the work area of the work zone	Workers or equipment too near traffic station	· Move equipment · Instruct workers to wear hard hats and safety vests · Instruct workers to stay as far as possible from traffic stream · Install Highway Advisory Radio
		Speeds too high or high variance in speeds	· Install rumble strips · Provide extra enforcement · Add advisory speed signs
		Access and egress of work vehicles into traffic stream	· Relocate work vehicle access and egress points · Have contractor furnish flaggers
		Insufficient work zone traffic capacity	· Provide alternate routes · Change work schedule to exclude peak traffic periods · Install Highway Advisory Radio · Reduce length of work area
5	Accidents or incidents on two-lane, two-way traffic operations on divided highways	Passing in no-passing zone	· Provide extra enforcement · Maintain tubes on centerline of two-way section · Use changeable message signs
		Insufficient work zone traffic capacity	· Provide alternate routes · Use changeable message signs · Notify media
6	Accidents or incidents on one lane sections with alternating direction traffic operations	Excessive vehicle queues and delays	· Reduce length of section
		Improper flagging technique	· Train flaggers · Move flaggers upstream
7	Accidents or incidents occurring at median crossovers	Insufficient crossover delineation	· Remove old pavement markings · Install new pavement markings · Install raised pavement markers
		Speeds too high or high variance in speeds	· Provide extra enforcement · Add advisory speed signs
		Shifting of cargo loads in trucks	· Provide extra enforcement · Add advisory speeds signs · Install raised pavement markings

PROBLEM IDENTIFICATION AND CORRECTION BY ACCIDENT TYPE
ACCIDENT TYPE		POSSIBLE PROBLEM	POSSIBLE TRAFFIC CONTROL CHANGE
1	Fixed object accidents	Narrow work zone roadway	· Widen roadway by moving channelizing devices or by using narrower devices · Improve reflectivity and delineation of devices
		Insufficient advance warning	· Move taper upstream to increase sight distance
2	Pedestrian accidents or incidents involving Pedestrians	Pedestrians on the roadway	· Install barriers between pedestrians and traffic · Restrict pedestrian movements
		Workers in or near traffic	· Install barriers between pedestrians and traffic
3	Truck accidents or Incidents involving trucks	Speeds too high or high  variance in speeds	· Provide extra enforcement · Add advisory speed plates · Use changeable message signs · Notify media
		Work zone roadway too narrow for large vehicles	· Provide truck detours
4	Head-on accidents or Passing conflicts	Divided highway with two-way traffic operations	· Shorten length of two-way traffic operation · Maintain channelizing devices on centerline · Provide extra enforcement · Notify media
		Slow-moving maintenance operations	· Require work train to allow vehicles to pass occasionally · Improve signing and lighting of work vehicle · Change work schedule to periods of lower traffic volume
5	Rear-end accidents or slow-moving vehicle conflicts	Insufficient work zone traffic capacity	· Provide alternate route · Change work schedule to exclude peak traffic periods · Reduce length of work area · Install warning signs
		Poor work vehicle access or egress to traffic stream	· Change work vehicle access or egress points · Have contractor provide flaggers
		Improper flagging technique	· Train flaggers · Move flagger upstream
		High variance in vehicle speeds	· Provide reasonable speed limits · Provide extra enforcement
6	Sideswipe same direction accidents, merging accidents, and lane change or slow-to-merge conflicts	Insufficient taper length	· Lengthen taper · Position arrow board near start of taper · Move taper upstream to increase sign distance
		Insufficient acceleration lane length	· Lengthen taper · Install yield or stop signs on on-ramp · Close on-ramp
		Incorrect taper placement	· Move taper upstream to increase sight distance · Position arrow board near start of taper
7	Run-off-road accidents or shoulder encroachments	Narrow roadway	· Widen roadway · Improve edge line delineation · Provide extra enforcement

PROBLEM IDENTIFICATION AND CORRECTION BY TIME-OF-DAY/WEATHER CONDITIONS
TIME/WEATHER		POSSIBLE PROBLEM	POSSIBLE TRAFFIC CONTROL CHANGE
1	Night accidents	Poor visibility or delineation	· Illuminate or reflectorize channelizing devices · Remove old pavement markings · Add temporary raised pavement markings · Add temporary pavement edge lines
		Equipment or vehicles stored near roadway	· Store vehicles and equipment at location away from roadway
2	Accidents or incidents during periods of peak  traffic volume	Insufficient work zone traffic capacity	· Provide alternate routes · Change work schedule to exclude peak traffic periods
		Access and egress of work vehicles into traffic stream	· Relocate work vehicle access and egress points · Have contractor provide flaggers
3	Accidents or incidents during weekend periods	Vandalized or stolen traffic control devices	· Furnish night watchman · Increase routine police patrols
		Trucks or recreational vehicles unable to negotiate curves	· Lengthen tapers · Use changeable message signs · Notify media
4	Accidents or incidents during inclement weather	Poor visibility or delineation	· Remove old pavement markings and replace with new pavement markings · Install raised pavement markers
		Poor drainage	· Improve superelevation · Patch low pavement areas · Prevent mud from washing onto roadway