A Boston police officer chasing a suspect ran past a brutal assault and was prosecuted for perjury when he claimed not to have seen it — so researchers ran their own test on such inattentional blindness:
We simulated the Boston incident by having subjects run after a confederate along a route near which three other confederates staged a fight. At night only 35% of subjects noticed the fight; during the day 56% noticed.
(Hat tip to Tyler Cowen.)
And that was just during a test… I bet the results would be even worse if some way could be found to more closely simulate the state a cop would be in while in hot pursuit of a possibly armed-and-dangerous suspect.