Inside this weekend’s downtown I-5 closure

• One freeway lane will remain open on the stretch, so local traffic can access freeway ramps. The Fifth Avenue ramp will be fully closed.
• Caltrans will close the same stretch to northbound traffic the weekend of Sept. 29.

Why it matters: As long as residents are aware of the situation, disruptions should be minor.

• "There will be delays, it will be an inconvenience, but as long as people heed warnings and take alternate routes, it should be OK," said Stephen Welborn, Caltrans District 11 spokesman.

State of play: Welborn said officials expect 70% of travelers to use I-805 south, which shouldn't experience congestion.

• Drivers taking the I-8 east detour will be able to use SR-163 or I-805 to head south.

Details: The $7 million project is funded through the Caltrans' emergency budget, same as repair work on SR-78 this year when a sinkhole forced a closure.

• "It's not an emergency like that, but it's something we need to get to before it becomes an emergency," Welborn said.

Flashback: It's been more than a decade since "Carmeggedon," the media hysteria around the closure of a 10-mile stretch of I-405 in L.A. that ended up not causing any problems at all.

UCLA transportation professors Martin Wachs and Brian Taylor studied that event and determined dire predictions fell flat because weekend travel tends to be discretionary, so residents simply changed their plans.