The former congressman from Illinois says in an interview with The Associated Press that he intends to remain at the department until his successor is confirmed.
LaHood has helped the Obama administration steer through a number of safety measures and highway projects during the past four years. His record has included steps to curb distracted driving, promote high-speed rail projects and improve roads and bridges.
Former Defense Secretary Robert Gates also was a Republican.
LaHood says he will not run for public office in his home state of Illinois, saying he believes "you should go out while they're applauding."