Washington - Olympic swimming champion Michael Phelps was arrested for drunken driving early on Tuesday after speeding and then crossing the double-lane lines inside the Fort McHenry Tunnel in Baltimore, Maryland Transportation Authority Police said.
Phelps, 29, was clocked by radar at around 01:40 travelling 135km/h in a 72km/h zone, police said.
The 18-time Olympic gold medallist was booked and released.Phelps, the most decorated Olympian of all time with 22 medals, was "unable to perform satisfactorily a series of standard field sobriety tests," police said.
Police said the officer followed Phelps's 2014 Land Rover onto northbound Interstate 95, through the tunnel, and pulled him over just beyond the tunnel's toll plaza.
The Baltimore native was cooperative "throughout the process," police said in a statement.
Phelps was charged in Maryland in 2004 for drunken driving when he was 19 years old.
He pleaded guilty to driving while impaired in exchange for 18 months' probation.
Representatives for Phelps could not be immediately reached for comment.