Mapquest might be adept at nailing down the shortest possible route, but that does you little good if the route is punishingly constipated with hapless fellow drivers. Get where you're going with My California Traffic.
MCT's a website showing real-time conditions on freeways statewide, using traffic speed data culled from copper wire loop sensors buried under the concrete (similar to the ones allegedly not embedded deep in your neck). Simply choose your region, then select a freeway and the direction you'll be traveling -- north, south, east, west, "away from that heartless bitch", etc. MCT then plots color-coded arrows (creatively, red, yellow, and green) on an interactive map that'll fill you in not just on average route speed, but also speed minimums at any given point -- so you'll know exactly where your grandfather's got off to in his Rascal.
MCT gets their info from the Freeway Performance Measurement System, a project that intends to "collect historical and real-time freeway data from freeways in the State of California in order to compute freeway performance measures" -- a hyper-literal missive that suggests the streets they study are not all that's constipated.