U.S. Transportation Secretary Norman Mineta plans to step down from his post July 7 after more than five years of service.

Mineta, 74, was the longest-serving transportation secretary in U.S. history, having taken up the post shortly after the Sept. 11, 2001, attacks on New York City.

He gained notoriety not only for being the lone Democrat in President Bush’s Cabinet, but also for his sweeping overhaul of the country’s transportation system, including the near-financial collapse of the U.S. airline industry.

A successor has not been named.

Mineta is expected to announce his future plans in the coming weeks.

Prior to taking his current position, Mineta served two decades in Congress and two presidents in Cabinet-level positions.