Effectiveness of Safety Vests in Nighttime Highway Construction

Many state agencies are shifting towards nighttime construction/maintenance especially on urban highways. While nighttime construction/maintenance has many advantages, it also has disadvantages compared to daytime construction. One major disadvantage is that nighttime construction operations may be more hazardous to both drivers and construction personnel because of visibility problems at night. Visibility depends on providing more luminance contrast to the driver than otherwise available. A system called LUMINA was developed to measure the luminance of six commonly used safety vests in nighttime construction/maintenance work areas. LUMINA was used (1) to perform field experiments that involved recording on videotape the performance of the safety vests; and (2) to convert the video movies into snapshots, to calculate the average luminance of the vests tested, and to index them. These tests were conducted not in a laboratory setting but on actual construction/maintenance sites that involved different lighting, traffic, and weather conditions. Two of the six safety vests outperformed the others significantly.