Benefits
Brighter Signs May Help Improve Safety
Some studies show that improvements in visibility reduce crashes and their costs.
Signs upgraded from ASTM Type I to ASTM Types III and IX deliver measurable benefit-to-cost savings. In before-and-after studies, researchers stated that "Implementation of highly reflective signs and pavement markings...showed statistically significant reductions in injury collisions following installation of highly reflective signs."(17)- A three-year program in Sioux City, Iowa, measured savings of nearly $5 million representing a 34:1 benefit to cost ratio.(17)
- A six-year Mendocino County, California, indicated savings of 159:1 to 299:1.(17)
- Controlled traffic studies involving enhanced signs indicated crashes reduced 25% (32) to 42%.(33)
- Older drivers clearly favored the visibility and legibility of unlighted guide sign groups (Type IX on Type IX and Type VII on Type III) over lighted sign groups which represents an improvement for these drivers plus provides added benefits in terms of electricity and lightning maintenance savings and reduced worker/traffic hazards.(34)
- Using high-performance retroreflective sheeting, Illinois DOT predicts that "the state could see savings of nearly $1 million a year in sign maintenance and energy costs."(35)
17 Ripley, D.A., Quantifying the safety benefits of traffic control devices—benefit—cost analysis of traffic sign upgrades, 2005 Mid-Continent Transportation Research Symposium Proceedings
32 Bagdade, J.S. Low cost intersection improvements reduce crashes for senior drivers. 2004 ITE Annual Meeting and Exhibit Compendium of Technical Papers
33 Ford, Evaluation of low-cost program of road system traffic safety reviews for county highways, TRB Record 1819, 2003
34 Zwahlen, H.T., et al, Field evaluation of unlighted overhead guide signs using older drivers, FHWA/OH-2003/015
35 http://www.dot.state.il.us/press/r011807.html for IDOT cost savings
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