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108 A 2001 review of 789 work zones in 13 states during summer months found that 33 percent of the projects reported work-zone activities or lane closures primarily at night (Wunderlich and Hardesty 2003). An additional nine percent reported continuous workâboth day and night. The duration of the night work closures reviewed clustered between 7 and 9 hours. Such dura- tions indicate that night construction work is usually conducted all night rather than just during one portion of the hours of darkness. This review also found that two-thirds of all resurfacing/paving activities were conducted at night but only one-third of the bridge work. In certain areas, transportation agencies are conducting all construction work at night. Even with these experiences, STAs still have misgivings about possible negative effects of night work. While there are disadvantages to working at night, a careful examination of the research and data supplied by STAs found that the perceived disadvantages are limited and can be controlled through good planning. In addition, the advantages of construction activities at night often outweigh the perceived disadvantages. Disadvantages and Advantages Table 11.1 shows a number of perceived disadvantages and advantages to nighttime construc- tion. Some are within the control of the transportation agency while others are outside direct agency control. The perceived disadvantages were, in many cases, determined to be unfounded by research, as indicated in this Guidebook. A number of very effective mitigation measures can be used to address the actual disadvantages. Frequent criticism about nighttime construction and the many perceived disadvantages are repeatedly recited; however, when examining the issues carefully, the difference between day and nighttime construction is not significant in terms of cost, productivity, quality, or safety. Good illumination and better traffic control are needed. Good planning can mitigate or limit the impact of all perceived disadvantages of nighttime construction. Planning needs to start during the very earliest stages of project development or, at the latest, when making the decision to conduct nighttime construction. This decision should always be made as early as possible in project development, as design decisions affect successful execution of night work. Lighting is critical for successful nighttime projects, and it needs to be quality lighting, which will add costs. Residential neighborhoods may find construction during nighttime hours more C H A P T E R 1 1 Summary for Implementation and Keys to Success
Summary for Implementation and Keys to Success 109 Table 11.1. Disadvantages, mitigation of disadvantages, and advantages of nighttime construction (Elrahman 2008). Factor Disadvantage Mitigation Advantage Illumination Need to provide good illumination Require an illumination plan and good lighting Nuisances Local ordinance may restrict work at night Require a noise control plan and limit equipment noise Can cause noise, vibration, light, and other disturbances Use new equipment, monitor work-zone noise Productivity Increased set up and removal time of traffic control and lighting Detailed traffic control planning Increased flexibility in work zone due to less traffic interference Reduced visibility of work area Provide proper illumination Less traffic interference and longer work shifts have positive effect on productivity A perception that there is lower productivity Need more detailed activity planning Allow more lanes to be closed temporarily Longer equipment repair time during breakdowns Use newer equipment, repair parts available, or provide backup equipment if schedule is critical Longer duration work periods Personnel scheduling may be more difficult Careful scheduling of activities and good communication Project duration decreased Restrictions may be imposed by unions or material suppliers Work with unions to understand restrictions and plan ahead with material suppliers to ensure adequate supply Biological clock factors, loss of sleep The Strategic Highway Research Program (SHRP 2) project R03: Identifying and Reducing Worker, Inspector, and Manager Fatigue in Rapid Renewal Environments is exploring these issues Employee satisfaction Quality Work quality may be affected negatively Provide good lighting based on work activities Cooler temperatures can enhance paving work Less aesthetically pleasing products Cost Need enhanced traffic control Good traffic control planning Decreased impact on businesses Need artificial illumination Good illumination planning Decreased impact on traffic Impact on trucking industry Communication Material delivery cost may be higher Decreased traffic interference Premium pay Safety More traffic accidents Good traffic control Lower traffic demand More work accidents Special training for nighttime workforce More conscious of safety practices Lower levels of speed enforcement Traffic delays decreased Driver fatigue and impairment Well-illuminated work zones and traffic control Workerâs perception of danger Better training required Communication Delayed project decisions Project staff need to have authority to make decisions in reasonable timeframes (especially at night, rather than waiting until the next day)
110 A Guidebook for Nighttime Construction: Impacts on Safety, Quality, and Productivity of a nuisance, but mitigation measures can limit the impact of the nuisances. The nuisance miti- gation measures should be written into the project special provisions. Beyond the few true disadvantages, the advantages are clearly apparent and careful planning can mitigate the disadvantages. The primary advantage of nighttime construction is less traffic interference with construction activities, which usually translates into better production and quality. Key Points for Success Research has shown that construction projects are more successful when there are greater lev- els of planning (Construction Industry Institute 1996). This means starting early in the project development process. Nighttime construction requires a detailed illumination plan, careful work planning and sequencing, traffic control, and nuisance mitigation planning. Planning needs to begin during the earliest phase of project development. Design decisions have a tremendous impact on the success of nighttime projects. Therefore, designers must be part of the construction planning team. Table 11.2 summarizes the keys to success for each of the primary areas of risk. Risk Area Keys to Success Illumination Provide proper illumination through planning and design to ensure productivity, quality, and safety. Nuisances Write nuisance control measures into the project specifications. Productivity Detailed planning and scheduling, with extra labor training, improve productivity. Quality Specify the desired quality; some activities benefit from cooler temperatures and less traffic congestion. Cost Decrease lighting costs by designing and phasing the project so that permanent lighting is installed early; consider the additional costs of lighting, nuisance mitigation, and traffic control in the estimate, but also consider productivity impacts of less congestion and longer work periods. Safety Priority one on every jobsite is safety, for the workers and the public; night work requires detailed traffic control planning. Communications Provide honest, timely information to the public regarding the project; authorize project personnel to make decisions by providing them with clear communication lines to obtain information. Table 11.2. Keys to success for each of the primary areas of risk.
