For the fourth and final time, two off-ramps will be closed on Doyle Drive this weekend.
The closures will allow construction crews to remove trees in the Presidio as part of the $1 billion project to rebuild the southern approach to the Golden Gate Bridge.
Construction will close the northbound and southbound off-ramps from Doyle Drive to Highway 1 from 5:30 a.m. to 11:30 a.m. Saturday and Sunday, according to project spokeswoman Molly Graham.
Tree removal this weekend will be the final part of the soft-construction phase of the rebuild. The swath of trees, which are mostly sycamores, are being cut down in an area just west of the existing Doyle Drive to clear space for construction of the new access route, which will be called Presidio Parkway.
Heavy construction on the Presidio Parkway project is scheduled to begin in November. The rebuild, which is expected to be finished by 2013, will completely replace Doyle Drive, which was built in 1936, with a more seismically sufficient thoroughfare.