when there's an accident one person always thinks the other one was going too fast; but it ain't necessarily so; and motorists' estimates of distance aren't great either. Imagine Matt braking in the road then quickly wheeling round backwards into a driveway; a following cyclist might well fail to see what was happening. Was it day or night? Did Matt have reversing lights/beeps? Were they working? You really need a lot more detail to answer this, and it's generally useful to have both sides of the story.