LOS ANGELES (CBS) — If you thought driving into downtown Los Angeles was already a headache, your aspirin supply is going to get a serious dent for the rest of 2011.

Caltrans plans to close a major on ramp for the remainder of 2011 and not expected to reopen it until Summer 2013.

Did someone say detour?

Starting this Sunday at 10 p.m. Catrans will close the 11th Street on-ramp to the northbound 110 (Harbor) Freeway. Caltrans previously closed the Olympic Boulevard off-ramp from the Southbound 110 Freeway.

The project is expected to cost $125 million and will … eventually … ease traffic congestion.

For detour information, click here.