Mendocino County, CA Sign Upgrades Reduce Crashes

Case Studies
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In the 1990s, MCDOT began a program to improve the signing and markings on all arterials, all collectors and a number of selected local roadways. This program consisted of completing a systematic review of roadways, identifying deficiencies, recommending corrective actions and reviewing the results. Each year one-third of the county roads (approximately 220 miles) are reviewed.

Early efforts concentrated on improving signing for curves and eliminating nonstandard signing. When new signs were installed, high-intensity retroreflective sheeting (American Society for Testing and Materials [ASTM] Type 3) was used. Prior to this program, all signs were constructed of engineering-grade retroreflective sheeting (ASTM Type 1).

The effectiveness of the program was measured by comparing crash data for roadways improved as part of the safety program to two control groups: county-maintained roads not reviewed or influenced by reviews and state highways within the county. Over a six-year period on the original 19 roads reviewed as part of the safety program, the number of crashes fell by 42.1%. Fatalities were down from 13 to 5, and injuries had decreased from 266 to 155. In contrast, the number of crashes on the non-reviewed county-maintained roads increased by 26.5%. On the state highways the number of crashes fell by 3.3%. Over the six-year period, the total program costs and savings were estimated at $79,260 and $23.73 million, respectively. Thus, the benefit-cost ratio works out to $299 in savings for every $1 spent.

The information contained in this article was summarized from a paper titled “Evaluation of a Low Cost Program of Road System Traffic Safety Reviews for County Highways” by Stephen H. Ford and Eugene C. Calvert presented at the Transportation Review Board’s 8th International Conference on Low-Volume Roads in June 2003 and is an example of a case study that will be a part of a new safety publication, “Low Cost Local Road Safety Solutions,” co-sponsored by the American Traffic Safety Services Association (ATSSA) and the National Association of County Engineers (NACE). The purpose of this project is to develop a publication consisting of a series of case studies that summarize low-cost roadway safety solutions that could be of interest to city and county engineers.

ATSSA has contracted with the Texas Transportation Institute (TTI) to develop approximately 20 case studies by synthesizing existing materials relating to low-cost roadway safety solutions. It is envisioned that these case studies will be available at ATSSA’s 36th Annual Convention and Traffic Expo March 3-7, 2005 in Fort Lauderdale, Fla. For more information on this event please visit . For more information on the “Low Cost Local Road Safety Solutions” project, contact Melisa Finley, assistant research engineer, TTI at 979/845-7596 or [email protected].

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