The last leg of the South Lawrence Trafficway should be built south of the Wakarusa River, County Commissioner Charles Jones said.

Not only would the southern route be less damaging to the environment and less intrusive for nearby Haskell Indian Nations University than a proposed 32nd Street route, Jones said, but also it would better relieve traffic congestion on some of Lawrence’s busiest streets.

Jones based his conclusions on a traffic analysis included in the project’s draft environmental impact statement. The analysis, compiled by the Kansas Department of Transportation, compared how much traffic area streets would carry in 2025, depending on which trafficway route was built.

All sections of 23rd Street would carry less traffic if the trafficway were built along a 32nd Street alignment, between Iowa Street and Kansas Highway 10 east of town, according to the study.

On average, that stretch of 23rd Street would carry 30,150 vehicles per day if the trafficway cut through the wetlands, according to data in the study. With a trafficway south of the river along a 42nd Street route, the daily average would go to 34,125.

But for other streets, judging by raw numbers used in the analysis, the daily traffic would be less if the trafficway were built south of the river.

Here are the projections for 2025, with averages taken for selected streets that would be affected by a trafficway either through the wetlands, along a 32nd Street alignment, or south of the river, along a 42nd Street alignment:

 Iowa Street, north from 33rd Street: 40,425 if through wetlands; 37,450 if south of river.

 31st Street, east of Iowa Street: 16,175 if through wetlands; 14,800 if south of river.

 Louisiana Street, from 31st north: 23,200 if through wetlands; 23,167 if south of river.

 Haskell Avenue, from 31st Street north: 26,067 if through wetlands; 24,367 if south of river.

Terry Flanagan, vice president for HNTB Corp., the Kansas City, Mo.-based consultant that compiled the draft statement for the corps, said the numbers weren’t surprising.

Area streets would carry a lighter traffic load, he said, because there would be less traffic on a highway south of the river.

“Fewer people would be using the 42nd Street alignment, and instead they’d be hopping on K-10 via 23rd Street,” Flanagan said.