The analogy is poor: on a live fire range the bullets move much more quickly than you. The speed of the bullets relative to you is largely determined by the bu

The analogy is poor: on a live fire range the bullets move much more quickly than you. The speed of the bullets relative to you is largely determined by the bullets, and your speed is irrelevant - so how fast you move is naturally irrelevant (assuming random fire, of course). The chance of collision will be determined largely by the number of bullet-meters made. If you will: it's as if the bullets are exploring the space in a probabilistic/ballistic fashion - the more bullets and the faster they go, the more they can explore. Conversely, when you hit something on the highway, it's likely to be moving much more slowly than you (e.g. the chicken crossing the road), or at a speed similar to you (the drunk guy driving on the left side). So your speed matters - you're more likely to reach that obstacle in any given period of time if you can explore more space in that time.