Details:

Creators:
Howell, Brian ; Pigman, Jerry ; Agent, Ken
Howell, Brian ; Pigman, Jerry ; Agent, Ken Less -
Corporate Creators:
University of Kentucky Transportation Center
Corporate Contributors:
Kentucky. Transportation Cabinet
Subject/TRT Terms:
[+]
Color Construction And Maintenance Equipment Light Emitting Diodes Recommendations Surveys Vehicle Lighting Systems Warning Systems
Publication/ Report Number:
KTC-15-06/SPR15-57-7-1F
Resource Type:
Tech Report
Geographical Coverage:
Kentucky
Corporate Publisher:
University of Kentucky Transportation Center
Abstract:
KTC reviewed existing regulations, guidance, and practices to assess the Kentucky Transportation Cabinet’s warning

lights program on highway work vehicles. The Kentucky Revised Statutes categorizes KYTC vehicles as “public safety

vehicles” and requires their use of amber lights. Because the use of red can be confused with emergency vehicles,

KYTC prohibits the use of red on work vehicles. At the national level, standards for warning light colors do not exist.

Rather, AASHTO provides guidance on roadway operations equipment and recommends the use of amber and white

lights as the primary warning light colors for highway vehicles. AASHTO guidance also prescribes the use of slow,

asynchronous flash frequencies; LED light sources; and placement of lights at high elevations and against solid-colored

backgrounds. The MUTCD provides little guidance in terms of warning light specifications, including color preferences.

A review of existing state agencies, including DOTs, concluded that amber and white are the primary light colors

currently in use across highway operations vehicles.

KTC conducted two external surveys to assess warning light products and practices within the U.S. The first survey

reviewed vendor LED products and revealed that LED lights are primarily available in the colors of amber, blue, green,

red, and white. Fluorescent yellow-green is not available. The second survey requested state DOT information related to

lighting systems’ colors, sources, intensity, and placement; responding agency names and policies; and previous state

DOT studies related to warning lights. Survey responses indicated 100 percent use of the color amber (as a color type) as

well as use of LED light sources. More than 75 percent of reporting agencies place warning lights on their highway

work vehicle’s roof to maximize visibility to motorists. Survey results varied dramatically on the differentiation of

warning light colors by vehicle type and the differentiation of light intensities for daytime versus nighttime conditions.

KTC researchers recommend the use of amber and white colors for KYTC work vehicles, an asynchronous flashing

pattern with slow flash frequencies, and LED bulbs. Other recommendations include placement of warning lights at high

elevations on the vehicle, placement of warning lights against a solid-colored background, and investigation on

feasibility of yellow-green LED lights


Format:
PDF
Funding:
SPR15-57-7-1F
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:94201ab2cc04480b4d44a29a9db51da129042954fb5c15ced4c5f6bec959f26c
Download URL:
https://rosap.ntl.bts.gov/view/dot/29552/dot_29552_DS1.pdf
File Type:

Supporting Files

• No Additional Files

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