There will be intermittent single lane delays on the Hood River Interstate Bridge for the next several days after an unknown large vehicle severely damaged a guardrail Thursday afternoon.  Port of Hood River Executive Director Michael McElwee says the damage occurred in what he termed a “hit and run” around 1:30 p.m., and while he noted the guardrails on the bridge are hit frequently, this is the largest amount of damage anyone can recall.  McElwee says the vehicle rode hard against the east side guard rail for about 260 feet.  Crews have knocked back sections of the rail that were sticking out onto the bridge deck, but the rail must be replaced.  A contractor will look at the damage Friday, and McElwee hopes repair work that will take several days can begin early next week.  Bridge users should expect delays at all hours.