A two-car accident at about 9:15 Tuesday morning blocked traffic exiting Interstate 680 southbound onto Sunol Boulevard.
The crash occurred between a silver Lexus headed toward Pleasanton and a blue Toyota exiting I-680 northbound, according to Pleasanton police Office Tom Hansen.
"The Toyota pulled out in front of the Lexus," Hansen said.
Both drivers were wearing seatbelts, which Hansen credited for minimizing injuries. The woman driving the Toyota was taken to Eden Medical Center in Castro Valley with a head injury, he said. The driver of the Lexus was not injured.
Because Sunol Boulevard heading into Pleasanton was blocked, cars were diverted back onto I-680 northbound to reach the city by alternate routes.