Work zone speed limit
Speed reductions are typically approved for traffic restrictions that remove recovery areas such as shoulder, narrow lanes below minimum standards; areas where equipment and workers are active next to traffic without positive barrier; and areas of two-way traffic on a one-way facility. Oftentimes, speed reductions are approved for detour streets when detour volumes substantially alter the way the system operates. Each situation is looked at for the impacts to both motorized and non-motorized traffic in order to determine the validity of speed reductions.
Speed reductions can apply to any type of roadway, depending on the added risk or travel difficulty posed by work zone traffic control and construction activities.
Static signs are required but these may be supplemented by PCMs. Ultimately, PCMs-speed limit signs will be primary. The Oregon DOT travel information web site, TripCheck, http://www.tripcheck.com/RoadCond/roadcondindex.htm, will be used to post where are speed reductions are for work zones on state highways.
Reductions are given for the traffic control layout, so speed reductions are in place only when the specific traffic control is in place. A time span of only several hours may be the case, or the entire time span of a project may be involved up to several weeks.
ODOT requires signs to be covered or turned away from traffic when not needed.
Flashing beacons are allowed if the sign/flasher combination is crashworthy. These usually include 2 diamond-shaped orange flag boards mounted on the top of the speed signs.
Various research projects are conducted to discover more active ways to manage speed zoning through work areas utilizing traffic operation centers. For the experimental efforts, trailer-mounted, LED-numeral SPEED LIMIT signs are used. The state has limited deployment, but so far, the response has been positive.