I would speculate that road, which due to cars have elevated noise levels, render them intrinsically a good cloaking mechanism to wolves stalking prey.
Or at least, deer feel unable to register sounds there and thus avoid it
The presence of predators causes prey to avoid areas that favor the predator. In this situation the issue is open space. Roads are open, wolves are a bigger threat to the deer with long sight lines.
(Simple example in our own backyard. Some plants in pots, some plants in the ground with vegetation around them. The birds completely stripped the ones in the pots but didn't touch the ones in the ground. There was no cover near the pots, a cat would have no cover. With the ones in the ground a cat would have lots of cover. While we do not have a cat multiple cats sometimes come around.)
Deer don't generally hang out on busy roads at the best of times. I suspect it has more to do with the roadway being an open area which makes the deer more visible and thus more vulnerable to wolves.
> Deer don't generally hang out on busy roads at the best of times.
Deer hang out wherever they find food and cover. If there happen to be busy roads in the vicinity then you find them on busy roads.
Busy roads also have lights; deer make use of available illumination. The frequency of deer collisions increases with the full moon because of this[1].
I have a light pole on my property and deer hang out near this. Almost every night I step outside I startle a few; there were two does under it last night.
Or at least, deer feel unable to register sounds there and thus avoid it