A series of sporting events, music festivals, conventions and Fleet Week has San Francisco preparing for large crowds, heavier traffic and security challenges in the next 11 days.
Crews will begin street closure for the events on Thursday night.
Agencies preparing for the influx in traffic said the city has experience handling big events. But commuters are not as confident and are planning for much longer waits than usual.
More than a million people are expected for Fleet Week alone.
"It's going to be really bad. It's going to be backed up a lot," said Sheila Lee, who commutes from Oakland.
This weekend, the San Francisco Giants end the regular season by hosting rival Los Angeles Dodgers at AT&T Park. Across town at Golden Gate Park, 750,00 people are expected for the Hardly Strictly Bluegrass Festival.
Next week, Dreamforce and Fleet Week will touchdown in the city.
"Last year we saw record attendance with 1.2 million people coming into San Francisco for Fleet Week," said David Cruise, with SF Fleet Week. "And we expect it to be larger this year."
From the Embarcadero to Chrissy Field, crowds will line up to see Navy ships and the Blue Angels.
San Francisco police said officers will be working overtime and stepping up patrols during the events.
Meanwhile, San Francisco Municipal Transportation Agency crews have posted signs throughout the city and on freeways providing detours and alternate routes.
The SFMTA is also advising people visiting the city to use public transportation, walk and ride bicycles. For those who have to drive, agencies suggest going online to reserve parking.
For more information on the events, street closures and transportation tips, visit the SFMTA website.