Well, it looks like this major trade conference that is bringing a bunch of world leaders from the Asia-Pacific sphere to San Francisco in a few weeks is going to snarl traffic and cause transit headaches way bigger than Dreamforce ever does.

We should have known that with the biggest gathering of world leaders in SF since the creation of the United Nations in 1945, there would be some major security involved with this thing.

We're now learning that the Secret Service is dictating an elaborate set of street closures, subway and bus interruptions, and the creation of a very large secure perimeter around the Moscone Center that will last for six day in mid-November — from Tuesday, November 14 to Sunday, November 19.

"San Francisco is proud to host the Asia-Pacific Economic Cooperation (APEC) conference in November, one of the largest gatherings of global leaders in San Francisco," says the SFMTA in an announcement. "This is an exciting opportunity for San Francisco to shine on the world stage. Most APEC activities will take place in the South of Market and Nob Hill neighborhoods. Due to the scale of the gathering, APEC may have some impacts on travel in other areas of San Francisco as well."

More than 20,000 people are expected to attend the summit and its ancillary CEO conference, and for those six days, only conference attendees and people who live in the perimeter will be permitted inside the secure zone shown in pink above.

Mission, Howard, and Folsom streets will all be completely impassable between Sixth Street and First Street, and it looks like movement on Harrison will be highly regulated too.

As you can see, Caltrans will also be closing the off-ramps just outside the perimeter, including the I-80 off-ramps onto Fourth Street and Fifth Street.

Additionally, many bus lines will be impacted, including 12-Folsom, 14-Mission, and 30-Stockton, and the T subway line won't run between Moscone Center and Chinatown — but shuttles will run between Union Square and Rose Pak Chinatown stations. The other end of the T line past 4th and Brannan will be served by the former KT line, which will run to Sunnydale.

The Chronicle confirmed the Central Subway news early Wednesday ahead of a press conference about these plans, and spoke to some Chinatown business owners who expect this will hurt their business.

"Instead of celebrating and showcasing the Central Subway to APEC and the world, it’s almost like we’re trying to turn our backs and do the opposite of that,” says David Ho, a consultant for the Chinese Chamber of Commerce. "I think it just speaks volumes to their confidence in their own security protocols that they can’t secure the underground."

Chinatown community leaders also say that they met with the SFMTA about the upcoming summit and its impacts on transit, but they walked away without much information — and the SFMTA has been deferring to the Secret Service.

Additionally, another Secret Service secure zone will be set up around the Fairmont Hotel on Nob Hill, where President Joe Biden — and presumably some other leaders — will be staying. This also happened last month when Biden was in town for a couple of fundraising events.

See the full list of Muni and street impacts during the APEC summit here.

Related: Newsom Gives SFMTA $3 Million to Clean These Damned Streets Before the APEC Summit