The project produced three stand-alone guidelines for illumination for nighttime highway work: (1) Illumination Guidelines for Nighttime Highway Work, (2) Guidelines for Work Zone Illumination Design, and (3) Guidelines for the Use of Temporary Roadway Lighting. These guidelines address relevant topics, including visibility requirements, lighting equipment, lighting configuration and arrangement, lighting system design, system operation and maintenance, and economic considerations.

An increasing amount of nighttime highway work is being performed on both divided and undivided highways in urban and rural settings to minimize the congestion effects of daytime reductions in capacity and/or to accelerate the work. This often necessitates the use of illumination to facilitate the work while maintaining a safe work area for the traveling public and the workers. Because nighttime work continues to increase in frequency and to avoid providing illumination on a trial and error basis, there is a need to develop illumination guidelines that identify the types of light sources and the minimum and maximum levels of illumination required for a variety of nighttime work in typical situations.

The research included a review of relevant domestic and foreign literature, survey of state departments of transportation (DOTs) to establish the extent of use of nighttime construction and maintenance work, and adaptation of illumination guidelines developed by other industry sectors to the specific needs of transportation construction and maintenance. Also, the research included field visits and monitoring of nighttime highway construction and maintenance activities on several projects to assess the suitability of the preliminary guidelines developed in an earlier phase of research and to provide a basis for developing improved guidelines. The research concluded that nighttime highway work can be performed safely and with a level of quality and economy comparable to that achieved from daytime construction. NCHRP Report 498 "Illumination Guidelines for Nighttime Highway Work" contains the guidelines developed in this project.