Having spent less than a year on the job, the head of the state's Department of Transportation handed in his resignation Wednesday, leaving a department that has had six leaders over the past five years.

Jeffrey Parker, a native of Newington, where the DOT is based, joined the department in August 2008 as a deputy commissioner and succeeded Joseph Marie as commissioner after Marie was forced to leave by Gov. M. Jodi Rell.

Parker's resignation is effective March 8, according to DOT spokesman Judd Everhart.

In his resignation letter to Gov. Dannel P. Malloy, Parker said his resignation would allow him more time to spend with his wife and children, and that he believed the DOT was prepared to meet future challenges. A reorganization of the agency to move more authority to the chiefs of individual bureaus within the agency should help ensure that important projects have enough oversight to guide them, Parker said in his letter.

"Under my leadership, the department has developed a strong senior management team, initiated fiscal reform to better manage the transportation capital program, completed many highway and transit projects, planned and initiated more projects, and won numerous federal discretionary grants," Parker wrote.

Parker was first hired by Marie to handle oversight of the state's $878 million, multi-year overhaul of the 70-acre New Haven Railyard at Union Station.

During his transition following his election, Malloy said that he would conduct a national search for applicants to take over the departments of Transportation, Education, Social Services and Environmental Protection.

Colleen Flanagan, a spokeswoman for Malloy, said that no choice has been made about selecting an interim commissioner, and the administration is continuing a nationwide search for an permanent appointee to fill the position.

Malloy has interviewed several candidates, but has no timetable to appoint a new commissioner, Flanagan said.

"The governor thanks (Parker) for his work at the DOT and wishes him the best going forward," Flanagan said.

In a separate memo to DOT employees sent Tuesday by Parker, he thanked his employees for their dedication to maintaining the state's highway and mass transit system.

"You have all shown me, through your dedication to public service, why being part of the department family is so special," Parker said.