Topeka ? Michael Johnston, the president and chief executive officer of the Kansas Turnpike Authority, who was thrust into the middle of a political battle this legislative session over control of the turnpike, announced on Friday he plans to retire from his position.

The announcement came one week after Gov. Sam Brownback signed into law a bill that would make his appointed secretary of transportation the director of operations of the Turnpike Authority, which oversees the 236-mile Kansas Turnpike.

Johnston said the new law was a factor in deciding to retire, but a “fairly minor” one. At age 68, Johnston said he had already been contemplating retirement. Johnston said he notified the turnpike’s board and employees Friday that he intended to leave, making his last day June 15.

Brownback and Kansas Department of Transportation Secretary Mike King have maintained that the new law will produce savings through efficiencies. But critics of the legislation called it a power grab by Brownback, a Republican, aimed at forcing out Johnston, who served in the Legislature as a Democrat.

Some Republicans also argued against the bill, saying the turnpike was efficiently run and should be left alone.

Others feared turnpike revenue would be used to pay for other areas of the state budget, which faces large revenue shortfalls because of tax cuts signed into law by Brownback.

Johnston said he wasn’t asked to leave, and he declined to comment on the new law, saying it was a policy decision within the prerogative of the Legislature and governor.

Brownback’s office issued a statement that said Brownback and Lt. Gov. Jeff Colyer thanked Johnston “for his many years of service to our great state and to wish him all the best in his retirement.”

Johnston joined the KTA in 1995. Prior to that, he served as KDOT secretary from 1991 through 1994. He served in the Legislature for 14 years.