Visibility

Reduced visibility, driver impairment or inattention, inadequate lighting, and lack of maintenance of traffic control devices are common problems identified with night work zones. These findings were consistent in the surveys of DOTs and VDOT residencies. Having police officers present, making workers more visible, using drums in the taper, keeping traffic control devices in good condition, and providing adequate lighting were common solutions offered by both sets of respondents.

Although there is a perception that night work zones are less safe than daytime work zones, the traffic exposure data are insufficient to draw this conclusion. Based on the limited amount of data gathered from our research, there was no evidence of higher speeds at night. There is, however, a need to improve the visibility of workers.

Based on the motorists’ survey conducted at selected sites and the onsite review of work zones, traffic control for night work zones, in general, is adequate. Nevertheless, common problem areas we identified included establishing work zones based on the Virginia Work Area Protection Manual, maintaining traffic control devices, and properly aiming and aligning lighting to avoid glare.

Improving Visibility of Traffic Control Devices

Use drums in the transition area for lane closures. Drums in the tangent section are optional.

Consider requiring the contractor to have full-time traffic control staff to implement and maintain all traffic control operations when deemed appropriate. The road workers should also make sure that the work lights are not creating glare for the motorists and that vehicle lights are not a distraction. The contractor’s and VDOT’s staff should make sure that the traffic control complies with the Virginia Work Area Protection Manual.

For all work zones with limited sight distance because of road alignment, shift the transition area upstream to improve the visibility of the flashing arrow board and the taper. Similarly, when a lane closure merge point is near an entry ramp, shift the transition area upstream to separate the two merge points.

Improving Worker and Work Vehicle Visibility

Require all workers to wear hard hats that have retroreflective material that is visible from all sides. Ways to make retroreflective clothing visible through the full range of body motions should also be considered.

Use the New York DOT guidelines for use of flashing and warning lights on work vehicles.

Managing Traffic

When a PCMS (portable changeable message sign) is used for night work zones, use messages appropriate for the existing road conditions. The PCMS should be considered for use as a warning device in situations where there is congested traffic ahead. It can also be used as an attention-getter later at night when traffic volumes are lower. When appropriate, the message TROOPER ON SITE, SPEED LIMIT ENFORCED should be used. The use of a radar-controlled PCMS should be considered as a countermeasure for speeding.

Position the police vehicle to maximize its visibility.

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