A truck struck the center guard rail on Interstate 5 at mid-Boeing Field yesterday morning, snarling traffic as far as the eye could see. The truck's trailer swerved into the rail after the driver hit the brakes to avoid a vehicle in front of him and lost control of it. Damage was minor and there were no injuries. State Patrol troopers have not yet decided whether to cite the driver. Photo: Phil H. Webber, Seattle Post-Intelligencer / Seattle Post-Intelligencer