The California Highway Patrol says traffic is again flowing smoothly through the checkpoint linking San Diego and Tijuana.
The world's busiest border crossing was shut down for nine hours after federal agents killed a man driving toward Mexico.
The driver, who was not identified, was pronounced dead at the scene with multiple gunshot wounds.
U.S. Customs and Border Protection agents began following a black SUV after somebody reported seeing it pick up suspected illegal immigrants near the U.S. side of the border crossing.
When the vehicle stopped and agents approached it, the driver veered hard to the left and attempted to get back in traffic.
That's when two agents opened fire.
Five passengers in the vehicle, whose identities were not released, were taken into custody and are being questioned.