Test air leakage rate: With a fully-charged air system (typically 125 psi), turn off the engine, release the service brake, and time the air pressure drop. The loss rate should be less than 2 psi in 1 minute for single vehicles and less than 3 psi in 1 minute for combination vehicles.
Construction on the Coronado Bridge began in 1967. Almost 500 prestressed concrete piles were fastened to the sea floor of the bay to provide the foundations for the bridge. The steel and concrete components were largely built offsite, then assembled together from marine construction barges over the bay.
A foghorn blared into the California dawn at 6 a.m. on May 27, 1937, to signal the official opening of the Golden Gate Bridge. That day, nearly 200,000 people walked, ran, tap-danced and roller-skated across what was then the longest suspension bridge in the world.