The San Francisco Police Department will establish a DUI checkpoint during Cinco de Mayo weekend in the Mission, according to a press release.

On Friday, May 4, the “Harley-Davidson Road Kings” will be out in full force, checking for any signs of drunk drivers.

Police will also establish a DUI checkpoint on May 5 at Cesar Chavez Street and South Van Ness Avenue, starting at 8:30 p.m., according to the release. The checkpoint will continue into the early hours of the morning.

You might wonder why cops announce DUI checkpoints in advance.

Here is one of the best responses I’ve seen online, from the Sacramento Bee:

“There are two reasons for advance publicity. It is a ‘best practice’ based on court rulings and effectiveness. The State Supreme Court said that advance publicity reduces intrusiveness of the stop at a sobriety checkpoint. The publicity and high visibility adds to their primary deterrence effect.”