HOUSTON -- A driver fell asleep Thursday, causing his big rig to crash and catch fire on the side of a northwest freeway, shutting down the highway for hours, police said. Investigators said the driver was traveling on Highway 290 inbound when he fell asleep, hit the guardrail and a side wall at Gessner Road at 2:15 a.m. The front end of his rig exploded into flames after fuel leaked. Gas also spilled down the side of the freeway, igniting another fire.