In four years, drivers are expected to have more room to spread out on the Kansas Turnpike between Lecompton and Topeka.

But starting next year, the more than 35,000 vehicles a day may need to bunch up a bit to make way for the $108.6 million expansion project.

“One of the objectives that we have in this project is, during the construction period, to maintain two lanes of traffic in each direction,” said Michael Johnston, president and chief executive officer of the Kansas Turnpike Authority. “We don’t, at this point — with the possible exception of a very limited number of days — see any reason we’d have to pinch traffic down to one lane in either direction at one time.

“It may not be 70 miles per hour all the way, but we’ve tried to plan.”

The plan calls for adding two lanes to the turnpike along the 12.7-mile stretch, considered among the fastest-growing sections of the 236-mile highway that runs from 18th Street in Kansas City, Kan., to the Oklahoma border directly south of Wichita.

With the additions — one lane in each direction, plus 10-foot shoulders on each side and a heightened centerline barrier to block headlights from shining into the eyes of oncoming drivers — the turnpike will be better able to accommodate the needs of an increasingly busy area, Johnston said.

The section last year handled an average of 35,000 to 40,000 vehicles a day, up from 30,000 a day two years earlier. The section’s use has spiked with the August 2001 opening of a new East Topeka interchange along the turnpike; the Lecompton interchange, opening up access to Lawrence’s South Lawrence Trafficway and U.S. Highway 40, opened in 1997.

“In view of the traffic growth we have experienced and are experiencing, we need to add capacity or service levels will decline measurably,” Johnston said. “Go to Kansas City at rush hour and you’ll see what a diminished service level is. You have more vehicles than you have space to carry them.

“That’s the same equation on the turnpike.”

The turnpike authority announced in December that it had hired HNTB Corp., of Kansas City, Mo., to handle the estimated $13 million job of designing the project and engineering its construction. Bartlett & West Engineers Inc., of Topeka, has been retained to handle site surveys and work up plans for acquiring the relatively limited amount of land needed to make room for the new lanes, Johnston said.

Contractors then will be hired to tackle construction of the stretch’s first major expansion since it opened in the 1950s. Expected to start in 2004 and last into 2006 or 2007, the project calls for replacement of dozens of bridges along the route, both along and over the turnpike.

Picking up the tab will be turnpike drivers, who in 2002 paid tolls that helped generate $70 million in revenue for the turnpike authority.

The project may trigger a couple years of inconvenience for drivers and noise for neighbors, but such is the price of progress, said Jere McElhaney, a Douglas County commissioner.

The additional traffic welcomed by the project should mean more people driving into Lawrence for business, he said, especially with all the activity generated by the Kansas Speedway in nearby Kansas City, Kan.

“The community right here needs to step forward and realize that we’re getting a lot of benefits for not a lot of costs,” McElhaney said. “We need to put out our welcome mat and say, ‘thank you,’ and be appreciative. We thank the Kansas Turnpike Authority for putting safety first and going for a more efficient roadway.”

Turnpike officials also have more work in mind for the Lawrence area: an estimated $131.9 million project to replace two turnpike bridge spans across the Kansas River.

The half-mile spans — one for traffic headed east, the other for vehicles going west — are located between Lawrence’s east and west interchanges, which also would be rebuilt at their current locations to better serve traffic, Johnston said.

The project is expected to start in 2009 and be finished by the end of 2012, the end of the bridge spans’ useful lives, he said.

As planned, each span would have room for three lanes of traffic, plus shoulders, Johnston said. Construction would be phased so that a new span would be built alongside the current spans, allowing traffic to be diverted to the new one while the old ones are torn down to make way for the second bridge.

“We’re obviously thinking 30, 50, 75 years down the road,” Johnston said. “If history’s any indication, growth will continue.”