The SFMTA announced that cars will be banned on several major streets for the 4/20 gathering on the east end of Golden Gate Park this Sunday.

From 10 a.m. to 6 p.m., cars will be banned on Kezar Drive, Stanyan Street between Frederick and Oak Streets, and Haight Street between Masonic Avenue and Stanyan.

Drivers swarming the area for the event — many from out of town and not necessarily in their sharpest state of mind — typically create a traffic mess in and around the eastern park. Illegal parking is rampant, Muni is brought to a halt, and sidewalks fill up. The car closures, the first of their kind for 4/20, could help simplify traffic flow, keep transit moving, and provide ample room for wandering.

Muni buses will be allowed through the pedestrianized streets, the SFMTA said, but “personnel from SFPD and SFMTA will determine to re-route Muni buses as crowds grow. Muni bus re-routes will be expected to begin at approximately 3 p.m.”

Supervisor London Breed and SFPD Chief Greg Suhr also held a press conference Wednesday to tell 4/20 revelers to keep things under control, promising a crackdown on parking violations.

Since 4/20 falls on a Sunday this year, the de facto Sunday Streets network will be complemented by the weekly car closure on John F. Kennedy Drive.