Caltrans will temporarily shut down a traffic signal at Highways 1 and 68 tomorrow in order to switch over to a new operating system. Motorists can expect the shut down from 9 a.m. to 3 p.m. tomorrow only, while the intersection will stay open with flaggers directing traffic. A 15-minute delay can be expected. The closure is part of a 2 and a half mile paving project of 12 on/off ramps which began on Highway 1 in Monterey from Eastbound Highway 68 to Westbound 68. Project completion is slated for the end of November.