Vehicle warning lights

Iowa DOT does not have written reports regarding tested use of warning lights. Lights are demonstrated by field test on vehicles to see if they are adequate, but no formal research projects have been done.

Rotating halogen lights are allowed on DOT vehicles. Additional rear directional strobes are allowed on snow removal vehicles.

All vehicles used within ROW are required to use lights.

The department has experienced some difficulties with short bulb life with halogen lights, angularity and daylight intensity with LED lights, and poor depth perception with strobe lights.

The department does not track the age and effectiveness of lights on state-owned vehicles.

The department requires warning lights for private contractor vehicles in work zones.

Lights are purchased per approved make/models, not specification.

The department has not approved any LED warning light for routine use. The department is currently field testing LED warning lights.

PSE amber dual halogen bulb rotating beacon lights are used on plow trucks. These are center-mounted in front of the dump body to rise with the dump body. There are also two rear directional Nova amber alternating with each other. Finally, there are quad flash strobes mounted in the dump box’s rear corner posts.