Traffic at the San Ysidro is now , effective Nov. 1st 2012, being routed through El Chaparral Garita (revision station) on the Mexican side of the border. As shown on the map; currently 5 lanes, takes traffic along the fence west to the new revision station, (garita).
The far right lane is for use by people who have something to declare or people who need to visit the customs or immigration offices to get a tourist entry visa or temporary vehicle import permit. There is plenty of parking for these services is next to the offices.
As the first ramp which heads towards Rosarito and Ensenada using the toll road is immediately after the station, it is best to be in the right lane for easy access to the ramp. Watch out for people attempting to change lanes quickly to aviod passing the ramp.
Traffic out of the station flows south east alone the river. The first ramp across the river, about a short block, takes you to the road leading to Playa's Tijuana, Rosarito, and Ensenada, For downtown stay to the left, (just past Plaza Viva Tijuana), provides access to downtown Tijuana (route market with signs).
The plans for the border crossing are to have traffic from the US sweep to the west across where the border parking is now and have all south bound traffic using the El Chaparral station. North bound traffic will be greatly improved as the lanes used now for south bound traffic become north bound.