WASHINGTON (AP) — Inaugural security teams are trying to prevent another "purple tunnel of doom" from President Barack Obama's first swearing-in.

The head of the District of Columbia National Guard said Wednesday that police will close the Third Street tunnel under the National Mall, where thousands of inaugural ticketholders were trapped in 2009.

Maj. Gen. Errol Schwartz said at a news conference that no pedestrians will be allowed, only emergency vehicles.

That was the plan four years ago. But barricades never arrived and many with tickets to the purple and blue sections were directed to enter the tunnel, where they got stuck for hours and couldn't see the ceremony.

A record 1.8 million came to see the first swearing-in of a black president. Military officials said they're expecting a smaller crowd this time.