Roundabout support based on shaky stats

In his 2018 State of the City address, Carmel Mayor James Brainard said:

“When roundabouts replace traditional signalized intersections, there is a reduction of fatalities by 90 percent, a reduction of injury accidents by 80 percent and a reduction of accidents overall by 40 percent.”

He cites no source for those claims. His own police department’s annual reports tell a different story.

In the years prior to any roundabouts, Carmel drivers suffered one or two fatalities; in the years since, one or two, and in 2007, three. No 90 percent drop there.

There were 200 injury accidents in 1995 and 207 last year; 686 total accidents in 1995 and 2,295 last year. That’s a 3.5 percent increase and a 70 percent increase.

Perhaps the mayor meant “rates” rather than raw number of accidents. In that case, the rate of injury accidents was 7.5 per 1,000 residents in 1995 and 2.2 last year—a 70 percent difference, not 80.

Police data do not break out traffic signal intersections, however. Where the mayor got those numbers remains a mystery.

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Bill Shaffer