A top official with the Washington area's Metro subway system says Wednesday's shutdown of the system was "necessary," and that safety problems were discovered.
At a Wednesday evening news conference, General Manager Paul Wiedefeld said that as of 5 p.m., inspectors had found 26 defects requiring replacement or repair.
He described three of them as "showstoppers" along McPherson, Farragut North, Potomac avenues. He called them areas "where we would not be running trains in these conditions."
However, he also said the system would reopen at 5 a.m., as expected.
As evening rush hour began, Maryland highway and police officials adjusted traffic rules to try to reduce congestion in light of the shutdown.
The Maryland Department of Transportation's State Highway Administration and Maryland State Police lifted the High Occupancy Vehicle (HOV) lane restrictions along eastbound US 50 between I-95 and US 301 in Bowie, and northbound I-270 between I-495 and MD 121. Normal HOV restrictions will resume at 5 a.m. Thursday.
Officials said drivers should plan ahead for longer trips.
The nation's second-busiest transit system subway was shut down for a system-wide safety inspection of its third-rail power cables after a series of electrical fires.
Associated Press reporter Joan Lowy in Washington contributed to this report.