The public roads and highways are designed to allow people to travel safely to their destinations. Occasionally, construction or maintenance work may temporarily block or reduce access to the full use of these roads. In cases where workers must control traffic flow and perform work in close proximity to road traffic, procedures must be followed to maintain the highest degree of safety to the worker as well as drivers and pedestrians. Work that must be done on or near roads presents hazards to workers, drivers, pedestrians, equipment and property. The possible number of fatalities, serious injuries, and large amounts of property damage can be greatly reduced by instituting and complying safety procedures for road work. Each work zone is unique and can present several challenges to establishing a safe work zone. Rolling hills and curved roads reduce distance visibility and may require adjustments to the usual procedures. Other adjustments to the standard work zone procedures may also be required such as several close intersections, darkness, rainy or foggy conditions, very heavy traffic, or even the time of year. Safe work zones must have an onsite supervisor that has a clear understanding of safety procedures and regulations and assure that their workers are complying with theses requirements. All traffic controllers must be properly trained, demonstrate a clear understanding of the safety requirements and perform the necessary tasks correctly. Both the onsite supervisor and traffic controllers must assure that proper signs, markings, barriers, lighting, and traffic controllers signals are in place, being effectively used, and will continue to be used until the project is finished. All workers in the work zone who will or may come within 12 feet of any moving traffic will wear a highly visible traffic safety vest. Where any part of the project is done within 6 feet of moving traffic, a protective perimeter will be established. All work will be done inside a perimeter marked with proper cones, traffic barriers, and proper signs. No workers should cross over this perimeter into the pathway of traffic. All vehicles, both worker�s personal and construction, must be parked on the same side of the road work to eliminate the need for workers to cross the path of normal traffic. Vehicular traffic must be warned that a work zone is ahead, not only to alert the drivers to be aware of hazards, but to also warn them that lane changes, detours, or temporarily blocked streets may appear. Warning signs must be placed in advance of the work zone. One to three signs placed in both directions from the work zone may be required to adequately warn drivers. The first warning sign should be placed 300 to 500 feet from the start of the work zone. Additional signs should be placed every 100 to 250 feet, depending on environmental conditions. On sharp curves, small hills, and very congested areas, signs should be placed closer together. Signs must clearly indicate the hazard: A �Flagger� (traffic controller) sign must be used if a Flagger is used. A �Lane Closed� or �Merge to One Lane� sign must be used if there is a taper. Reflective and/or lighted signs must be used if the signs are to remain posted after sundown. Warning signs should also be placed at cross streets or intersection inside the traffic control zone. Signs must be visible to drivers over parked vehicles and other obstructions. Signs must always be removed if their message no longer applies to the work control zone. Transition areas or moving traffic out of its normal path are a dangerous hazard, causing the most number of accidents involving workers. Transition areas also create potential accident problems for vehicle drivers because of confusion, frustration, and the �stop-and-go� traffic mode. Vehicle traffic flows much better if adequate warning is given and drivers respond to the warnings. The traffic control plan must provide the proper taper and preparation for utilizing it. The taper length must be carefully designed, signage properly posted, geometry checked, and critical clearances maintained. The proper number of cones must be deployed and correctly spaced. It is critical that the taper layout and components be regularly monitored to ensure that signs and cones are replaced after being knocked down or pushed out of place. The function of channel devices are to warn and alert drivers of hazards created by construction or maintenance activities in or near the path of traffic, to protect workers in the work zone, and to guide and direct drivers and pedestrians safely past the hazards. Channel devices include cones, vertical panes, drums, barricades, and barriers. The use of channel devices is a part of the overall the traffic control plan which is developed by the onsite supervisor to maintain the orderly and safe flow of traffic through and around the work zone. The placement of channel devices should provide a smooth and gradual transition in moving traffic from one lane to another, onto a bypass or detour, or in reducing the width of the path of traffic. They should be constructed so as not to inflict any undue damage to a vehicle that inadvertently strikes them. A merging taper is used to close a lane on a multilane roadway and to direct traffic in the closed lane to merge into the adjacent lane. Adequate length must be provided for motorists to locate a gap in the adjacent traffic stream and to move into it. The taper should be long enough so that drivers of vehicles approaching side by side have sufficient length in which to adjust their respective speeds and merge into a single lane before the end of the transition. In situations where the work zone must remain intact during the dark hours, all channel devices and barricades must be marked with reflective material and, where possible or necessary, lighted. Flashing lights should be added to barricades used singly and steady burning lights added to series barricades used as channel devices.
