Use of drone radar and safety intrusion alarms in work zones

Caltrans has used radar speed trailers in work zones and has experimented with other drone-type speed advisory devices. The devices have been effective, especially on high-speed interstate freeways frequented by truckers. Personnal have not experienced any negatives. They have used the devices in both rural and urban stationary work zones. Drone radar and radar speed advisory devices are an effective method of reducing speeds through work zones in areas where the use of radar detectors is prevalent, i.e., interstate highways, trucking corridors, etc.
Caltrans has used safety intrusion alarms in work zones. Types of safety intrusion alarms used include Infrared and Microwave. The devices were used informally in field trials and were not perceived to be very effective. They were subject to false alarms. Caltrans does not have written reports available on the field trials, but work crews were not at all positive about the use of safety intrusion alarms.