New electronic signs will blink on Thursday in an attempt by traffic engineers to help motorists on one of the most congested sections of highway in the Bay Area avoid even more traffic misery. More than 110 advisory signs will be activated on the 20-mile stretch of westbound Interstate 80 between the Carquinez Bridge and the Bay Bridge and on surrounding roads, said Shannon Brinias, spokeswoman for the California Department of Transportation. The electronic messages, mounted on 11 overhead structures, will display green arrows to indicate the lane is clear, a yellow X to alert motorists that there is some kind of issue ahead and a red X, meaning the lane is blocked up ahead, Brinias said. The idea is to alert motorists about trouble ahead so they can change lanes, which will hopefully ease commute gridlock and clear the way for emergency vehicles, said a Caltrans advisory.