Work zone speed limit
New Hampshire DOT does not have any formal policy in place regarding speed limit reductions in work zones. In their coordination meetings, the Bureau of Highway Design and Bureau of Construction decide if the speed limit should be reduced and whether the speed reduction should be in place throughout the duration of construction or whether it can be limited to within a certain work activity. If the reduction will be in place for the duration of construction, it is implemented as a “permanent” reduction and resembles the conventional speed limit signing.
Regulatory signs are covered during the time they do not apply. If speed reduction is temporary, whether for the day or even for a continuous short duration, the contractor has the option of reducing the speed using trailer-mounted flashing speed limits signs (by pay item in the contract). They commonly use portable changeable message signs (pay item) for real-time messages during the work, which also may include speed reductions. The intent is to restore the former speed limit where it can be done safely, recognizing that motorists will ignore speed reductions if there is not a perceived need to slow down.
Facilities with higher speed limits are often looked at more critically, say those that have speeds of 50 mph or higher. If necessary, the speed will be reduced by 10 mph. Sometimes, although not often, the speed will be reduced another 10 mph. As with any speed reduction, compliance is often a problem. Sometimes one of the only ways to get traffic to slow down is by using uniformed officers with police vehicles (blue lights flashing) for both presence and enforcement. Virtually all NH work zones are signed informing motorists of double fines for speeding through the work zone, i.e., $250 to $500.