Studies identify keys to safer roads

Older cities fare best

Steve Hawley, Jan 28, 09.

Two University of Connecticut researchers studying traffic accidents in California have identified intersection density as a key element in street safety, according to New Urban News. According to their results, “the most unsafe cities in California, in terms of traffic fatalities, are the newest ones — those developed primarily since 1950. The cities with the fewest fatalities, by contrast, are those with significant portions built before 1950.”

As suburbs spread, traffic specialists preferred long, branching street networks with few intersections because these networks “made neighborhoods quieter and presumably safer.” However, the new study found that cities with small city blocks and many intersections were safer, most likely because traffic traveled at slower speeds. According to the article, “the most dangerous cities had 41 percent fewer intersections per square mile” and suffered 10.1 fatalities per 100,000 population, compared to 3.1 fatalities per 100,000 people in the safest cities.

The article notes, “A recent report from Europe found that when average vehicle speeds drop by just 5 percent, the number of injuries drops by 10 percent and the number of fatalities falls 20 percent. Extensively connected street networks may not have fewer crashes over all, but the crashes that occur are less likely to leave someone dead.” Another recent study found that “street networks containing many cul-de-sacs increased travel demand on arterial roads by 75 percent and on collector roads by 80 percent, compared to a gridded street design,” which may also help explain the increased fatalities.

January/February 2009 issue of New Urban News

Photo by David Shankbone