"Trucks OK" on bridge overpasses

Dear Matthew Alice: I have always wondered what the sign on bridge overpasses “Trucks OK” over the number-two lane means. — Craig J. Hamren, National City

By law, trucks are not OK on highways outside of the two right-hand lanes. But sometimes those are exit lanes. So instead of shuffling semis off to a place they don’t want to go, the sign gives them permission to move to the left and keep on truckin’.