Work zone speed limit
Nevada DOT has a flexible approach to reduction of speed limits when lane widths are reduced, when lanes are closed, shifted or detoured, when bridge false work is necessary, etc. Speed reductions are also utilized when it can eliminate unnecessary impacts to business access points or high-volume intersections by reducing the lengths needed for lane tapers, shifts, etc. This has worked well, especially on urban street locations.
Nevada DOT policy allows speed reductions on any DOT-maintained roadway, as long as the need to reduce the speed is justified during preliminary traffic control and constructability meetings prior to the project being advertised. In addition, the policy allows reductions on any roadway with a posted speed higher than 55 mph to be reduced to 55 mph, as previously approved by the Director. If additional speed reductions are required under 55 mph or on roadways posted at 55 mph or less, written justification must be approved by the Director.
Notice is given to motorists using REDUCED SPEED AHEAD signs followed by the appropriate SPEED LIMIT sign. Typically, 10 mph or multiple increments of 10 mph reductions are used, depending on the total speed reduction required. Nevada places the REDUCED SPEED AHEAD and SPEED LIMIT signs prior to any construction signs so that (hopefully) motorists have reduced their speeds prior to the need for lane shifts, closures, detours, etc.
Temporary speed reductions are to be in effect only when the need for the reduction is evident. Nevada does have double penalty laws that allow citations to be given if work or workers are not present, as long as the need for traffic control devices on the roadway is necessary.
Nevada requires temporary speed limit signs to be covered, laid down, or removed when the need is not present. This has been hard to enforce with contractors and often the reduced speed signs are in place for long durations.
Nevada used to place flashing warning lights on signs but has discontinued this practice since the initial NCHRP350 Report was first released and it was unclear if lights attached to signs would meet the crashworthy criteria. Nevada requires that all signs be a minimum of a Type III (high-intensity) sheeting for regulatory signs used, whether for construction purposes or for permanent installations. All other construction signs are required to have fluorescent orange “diamond grade” sheeting, thus further reducing the need for flashing warning lights. In permanent speed reduction installations with high-intensity sheeting, flashing lights have been used, although motorist compliance is often not affected.