John I. Gilderbloom, a professor at the University of Louisville and prominent “new urbanist,” has produced a study that makes some dramatic claims about the benefits of converting one-way streets to dual traffic.

His most surprising: that two-ways cut crime significantly.

Given reader interest in our story last week about a city-commissioned look at two-waying Calvert and St. Paul streets, we thought Gilderbloom’s findings were worth describing.

He and a team of graduate students examined the “before and after” conditions of two one-way Louisville, Ky., streets switched to dual traffic in 2011 – and compared the results to two nearby unconverted one-ways.

After the conversions took place, Gilderbloom wrote, crime dropped 22% on the two-ways. “Auto theft alone has decreased by almost a third on the converted streets, even as it climbed by 36% on the nearby one-way streets. At the same time, there was a 42% reduction in robberies on the converted streets.” (Overall, Louisville experienced a 5% rise in crime in the 2011-13 period, he said.)

Socio-economic Profile

The streets he examined have a somewhat lower socio-economic profile than St. Paul and Calvert streets – 80% renter, with household incomes ranging from low to moderate. The racial mix of whites and blacks was evenly split.

The biggest change from two-waying Brook and First streets was the shift in their personality from fast and furious speedways harboring shady characters to areas under reclamation by same-sex couples, hipsters, retirees and others. “The sight of dumpsters, scaffolding and home improvement trucks have replaced prostitution, drug dealers, and fencing operations,” he wrote.

Some of the best returns on real estate investment in Louisville are now found on
these streets, the report claims. “Property values have increased on two-way streets while nearby one-way streets have declined. The now two-way Brook Street has seen a 39% increase in property values after conversion, according to records from the Property Valuation Administration.”

We imagine there were other factors at work in this rosy outcome.

Gilderbloom concedes as much, writing, “While there is no magical, quick-fix when it comes to turning around neighborhoods, converting multi-lane one-way streets to two-way streets is a smart and affordable policy. Neighborhoods will also blossom if one-way conversions are coupled with other proven infrastructure improvements, such as street trees, bike lanes, community gardens, public art, and adaptive reuse of abandoned properties.”

His findings were published in Planetizen.com last week.