Fatal accidents in nighttime vs. daytime highway construction work zones David Arditi a , Dong-Eun Lee b, ⁎ , Gul Polat c a Illinois Institute of Technology, Department of Civil and Architectural Engineering, Chicago, IL 60616, USA b Kyungpook National University, School of Architecture & Civil Engineering, DaeGu, 702-701 South Korea c Istanbul Technical University, Istanbul, Turkey Received 7 September 2006; received in revised form 6 April 2007; accepted 25 April 2007 Available online 16 July 2007 Abstract Introduction: Awareness about worker safety in nighttime construction has been a major concern because it is believed that nighttime construction creates hazardous work conditions. However, only a few studies provide valuable comparative information about accident characteristics of nighttime and daytime highway construction activities. Method: This study investigates fatal accidents that occurred in Illinois highway work zones in the period 1996–2001 in order to determine the safety differences between nighttime and daytime highway construction. The lighting and weather conditions were included into the study as control parameters to see their effects on the frequency of fatal accidents occurring in work zones. Results: According to this study, there is evidence that nighttime construction is more hazardous than daytime construction. The inclusion of a weather parameter into the analysis has limited effect on this finding. Impact on Industry: The study justifies establishing an efficient work zone accident reporting system and taking all necessary measures to enhance safety in nighttime work zones. © 2007 National Safety Council and Elsevier Ltd. All rights reserved. Keywords: Safety; Accidents; Nighttime construction 1. Introduction The first study addressing differences between daytime and nighttime highway construction was conducted in Colorado back in 1986 (Price, 1986). Comparing the quality and cost of daytime and nighttime projects, Price concluded that the material delivery at nighttime was more efficient due to less traffic but temperature extremes could have an adverse effect on crew and equipment performance. Ellis and Kumar (1993) investigated differences in cost and produc- tivity between daytime and nighttime construction in Florida. They found that there is no significant difference in productivity, but that nighttime projects cost less. Dunston, Mannering, Nam, Lee, and Savage (1998) found that the weekend closure strategy implemented in Washing- ton State improved quality and productivity over nighttime construction. Ellis and Amos (1996) developed work zone lighting standards for nighttime highway work. Researchers have also noticed the potential adverse effects of nighttime construction on quality (Hinze & Carlisle, 1990; Price, 1986). Concerns about reduced visibility, increased traffic speeds, and the higher frequency of drunk or sleepy drivers after dark limit the use of the nighttime construction alternative. But nighttime construction is being conducted more and more in many states in recent years (McCall, 1999) because nighttime construction/maintenance is expected to mitigate the impact of construction operations on the traveling public (less congestion), to lead to improved productivity (less interference), to achieve safer work practices (reduced exposure to the traveling public), to operate in cooler working conditions versus daytime temperatures during summer months, and to obtain quicker material delivery cycles (less machinery idle time). However, awareness about worker safety in nighttime construction has been a major concern because it is believed that nighttime construction creates hazardous work conditions. The biennial audit report of the Journal of Safety Research 38 (2007) 399 – 405 www.nsc.org ⁎ Corresponding author. Tel.: +82 53 950 7540; fax: +82 53 950 6590. E-mail addresses: arditi@iit.edu (D. Arditi), dolee@knu.ac.kr (D.-E. Lee), gpolat@ins.itu.edu.tr (G. Polat). URL's: http://www.iit.edu/~arditi (D. Arditi), http://www.webbuild.knu.ac.kr/~cm/ (D.-E. Lee). www.elsevier.com/locate/jsr 0022-4375/$ - see front matter © 2007 National Safety Council and Elsevier Ltd. All rights reserved. doi:10.1016/j.jsr.2007.04.001