Other mistake: Right before Barney gets hit by the bus, he's on the sidewalk. To the right there is a One Way sign pointing right, but the bus hits him driving left. The bus would have been driving the wrong way on a one way street.
Suggested correction: Not only is this not a mistake (it wouldn't be the first vehicle going the wrong way down a one way street), but we even see Barney looking in the direction of where the vehicles should be coming from and assume himself to be safe. Had the bus not been going the wrong way, Barney would have seen it coming and not been hit.
This is irrelevant. The mistake is that the bus is going the wrong way on a one - way street. While people do break the law like this, a bus driver certainly wouldn't.