UPDATED, 1:55 p.m. The District's taxi regulators impounded an illegal cab near Nationals Park on Wednesday, and a city official said authorities were on alert for more potential problems.

Neville Waters, a spokesman for the D.C. Taxicab Commission, confirmed that hack inspectors impounded a single vehicle, but he knew of no other problems ahead of the start of the third game of the National League Division Series.

(View a photo gallery of scenes from Nationals Park on game day)

Waters said inspectors would continue to monitor taxis around the ballpark as the game winds down later Wednesday afternoon.

"There is an expectation that as the game nears its conclusion, the odds of violations could increase," Waters said.

District officials said last week they would deploy up to eight taxi inspectors near the Southeast Washington stadium to handle matters related to the playoffs.

ORIGINAL: Depending on how far the Washington Nationals advance into the postseason, the District may have plenty of time remaining for tests of its plans for the Major League Baseball playoffs. And shortly before Wednesday's first pitch at Nationals Parks, early assessments from fans gave the city high marks.

Security at Nationals Park was tantamount, and the Metropolitan Police Department deployed dozens of officers to the stadium and put hundreds more on standby in case of trouble.

Mike Zawsky, a fan from Maryland, said he noticed the heightened police presence.

"I've only been out here twice during the season, but there seems to be a little more security," said Zawsky, who added he wasn't worried about problems at the high-profile National League Division Series game.

Police officers were roaming Half Street, the road leading to the ballpark's centerfield gate, encouraging ticket scalpers to move along or face the possibility being issued a citation.

But most scalpers were unmoved and continued to seek patrons by asking would-be attendees if they had tickets they wanted to sell. Despite the police department's warnings, scalpers were regularly making deals, especially in the moments after an officer passed through the area.

Even though scalpers were officially barred from the area near the ballpark, one fan said he had spied a few entrepreneurs well away from the stadium trying to unload tickets.

"I wasn't worried about the scalpers because I already had tickets, but they were further out," Jeff Henneman, a D.C resident, said. "I had them at Chinatown at the Metro."

Zawsky, who was trying to shed an extra $200 ticket he had procured, doubted he was going to be able to make a sale.

"I'm trying to sell a ticket for what I paid for it, but I ain't going to be able to do it," Zawsky said. "I've got a couple of friends coming, and I've got one ticket left."

Although security arrangements consumed most of the attention for the city's playoff planning, District officials also said they were ready for possible transit troubles.

Although nearby streets have been closed since 7 a.m. Wednesday, traffic was flowing close to the ballpark as District Department of Transportation employees kept watch on most street corners. The agency has said it will adjust timing on stoplights to keep cars moving through the area and will scramble to clear disabled vehicles.

Most fans, though, were poised to use Metro to get to the ballpark. The transit system said its trains were operating normally throughout the D.C. area, including on the all-important Green Line, the only route with direct service to the stadium.

Examiner intern Abby Hamblin contributed to this report.