A Superior Court ruling today dealt a blow to Mayor Antonio Villaraigosa’s plan to configure Pico and Olympic boulevards so they act as one-way streets.

County judge John Torribio said the controversial plan, backed by the mayor and other local officials, would significantly impact Westside traffic and must be subjected to a lengthy study of the effects on the area.

The plan would add lanes and eliminate street parking during rush hour to encourage drivers to take Olympic west and Pico east. Officials have touted the strategy as a way to help relieve traffic in the area.

Monday’s ruling was a win for some local business that had filed an injunction to halt the project, saying the changes would drive away customers.