"TRB's National Cooperative Highway Research Program (NCHRP) Report 726: A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity provides suggested guidance on the conduct of nighttime highway construction and maintenance operations. These guidelines are based on best practices and strategies for nighttime operations that relate to the personnel and traveling public safety and the quality of the as-built facility. The guide also addresses work-zone risk analysis planning and implementation, construction nuisances to both neighbors and workers, and work-zone illumination methods."--Publisher's description.

Report synthesizes existing literature on nighttime construction operations, identifies gaps in the current state of knowledge, and summarizes research in progress studies that are planned or underway. The literature review and synthesis found the following: there is no statistically significant difference between nighttime and daytime operations in terms of safety; there is no difference in productivity levels between nighttime and daytime operations; quality of work does not seem to be affected by working at night; user cost decreases when work is performed at night; there is no consensus on whether construction cost increases or decreases for work at night; nighttime work may affect worker health negatively, as in any other night shift work; traffic congestion and delays are significantly reduced or eliminated with nighttime operations, which in turn leads to air quality improvement; noise pollution and vibrations can be of concern to neighboring community for nighttime as well as daytime work; and new technologies are effectively addressing concerns over light pollution during nighttime operations.

The increased demand on the current highway system has caused transportation agencies to increase scheduling for nighttime work in order to alleviate daytime work zone congestion, especially during peak traffic hours. Although traffic congestion is reduced, safety in nighttime workzones remains a concern among both transportation agencies and contractors. According to the Federal Highway Administration (FHWA), approximately one-half of the fatalities that occurred in workzones nationwide occurred at night. These work zone statistics have received increased attention among agencies to evaluate planning and safety issues concerning the workers and the general public on nighttime workzones. Four separate, but interrelated research studies were conducted between September 2005 - May 2007 to address safety issues in nighttime construction and maintenance projects on highways in Indiana. The first study investigated owner and contractor safety management planning for nighttime construction and maintenance operations, while the second study investigated traffic control planning and implementation procedures for nighttime construction and maintenance operations. The third study investigated the effectiveness of speed control measures on nighttime construction and maintenance projects and the fourth study evaluated the effectiveness of high-visibility personal protective equipment practices.

This synthesis report describes current practice in mitigating nighttime construction nuisances such as noise, vibration, light, and dust. Roadway construction work is increasingly done at night to mediate traffic congestion; however, this trend also increases the potential for disturbing adjacent property owners. This report will be of interest to department of transportation (DOT) construction, design, and project engineers, and to those responsible for community relations. This report of the Transportation Research Board stresses the importance of informing project neighbors and establishing cooperative relations with the community as a first measure of successful mitigation. Examples show how project design can address construction nuisances by locating and sequencing construction operations to minimize their impact. Current practices used in source control, path control, and receptor control are described and documented in examples from the Boston Central Artery/Tunnel project and projects in Arizona and Salt Lake City, Utah. Appended materials provide sample specifications for mitigation of noise and dust control.