It takes David Schauner 15 minutes to drive from his west Lawrence home to downtown.

But the city’s streets are getting so congested, he said Monday, the trip might soon take him 20 minutes. Or even half an hour.

“Pretty soon,” he said, “there will be a disincentive to go downtown.”

That’s why Schauner, a Lawrence city commissioner, backs an ordinance that would require developers to mount traffic impact studies for all but the smallest new construction projects. Schauner said the studies would help city officials prevent traffic gridlock from ruining Lawrence’s livability.

But other officials raised a different possibility: Those studies might make city housing even more expensive.

“I don’t want to put an unnecessary constraint to boost the cost of housing,” Commissioner Sue Hack said. “I just want to make sure that if we do these studies, they truly are necessary.”

The ordinance, to be considered tonight by the commission, would require developers of all new nonresidential developments — and all new residential developments containing more than 11 lots — to pay for traffic studies before breaking ground on the projects. The study results would be furnished to city officials, who would use the document to decide whether the project should go forward.

“Knowing more about traffic flow, what impact a development will have on traffic, is important information,” Schauner said. “Unless we have that database, we won’t be able to factor that information into making good decisions about our comprehensive land-use policy.”

Otherwise, he said, you get traffic messes like the waits for left turns at 23rd and Iowa streets.

City commissioner David Schauner is lobbying to pass an ordinance tonight that would require developers to conduct traffic impact studies for all nonresidential development, or any medium-to big-sized residential development. This photo, taken Monday, looks south down Iowa Street from 19th Street. Schauner hopes to help Lawrence avoid traffic snarls like the ones near 23rd and Iowa streets in the future.

Bobbie Flory, executive director of the Lawrence Home Builders Assn., agreed — to a point.

“We think the city formalizing and clarifying when a traffic study is required would be helpful,” she said, “so a developer would know what his costs would be as he goes through the process.”

But, she said, a typical traffic study might cost $2,000 to $4,000. That’s a considerable added cost for a development containing only 11 new houses, Flory said.

Traffic impact studies, she said, should be limited to developments in high-traffic or high-accident areas.

“If it’s not, it’s just going to unnecessarily raise the cost of housing in these smaller subdivisions,” Flory said

¢City traffic engineering¢City policies on speed humps, speed cushions¢City traffic ordinances

The Lawrence Chamber of Commerce agreed. Outgoing Interim CEO Jean Milstead wrote commissioners in late May, warning against the effects of study costs on housing prices.

But Schauner is skeptical of the assertions.

“Housing will be less attractive if people can’t move in their car from their house to the grocery store,” he said. “Information isn’t going to make housing expensive. Information will help us to make housing more affordable.”

The commission meets at 6:35 p.m. today in City Hall, Sixth and Massachusetts streets.