+2, because the faster driver is more likely to miss something coming from the side -- or whoever's coming from the side is less likely to see the faster driver. For example, somebody backing out of their driveway, even doing it carefully with a few backwards looks and frequent mirror checks, could assume that it's clear to move farther out. Then, in just a second's time, the fast-moving truck gets close enough to become visible, which is usually too close to respond safely, if at all.

I don't like how fast the slower driver rolls through intersections, either; that's just too fast to get a good look from a car (I don't even go that fast through an intersection on a bike, and it's got better visibility). But, to pick one, I'd say that the faster driver is less safe.

It's a close call, though...