I see no reason not to blame the driver either. When you somehow drive your car into a still standing object in the road (the fire truck), then clearly a wrong judgement was made. Clearly the fire truck didn't move, so the blame is not there.
1. The driver should never drive faster than he can stop within half the distance he can see ahead. Clearly he couldn't stop for the fire truck.
2. And you obviously never change into a lane if you cannot confirm that the lane is clear ahead. Because then you violate rule 1, because you cannot stop if the traffic happens to stand still in the lane you switch to.
Clearly both of these rules were broken and could've been prevented. Blindly trusting the car to stop, or not interviene when it accellated. I'll not blame someone for something I don't know, but typing on a cell phone or distracted with other things usually cause these things...