I have a few nice looking spots I would like to set for cats. These spots are just off a fairly busy mountain pass road. My question is, will these cats frequent areas with more traffic?

Depends on your area and on how bold each individual cat is. Some may run along roads, or cross over them without a second thought, others may be hanging back about a mile from roads to avoid human interactions. One set I've always found to take cats is a log crossing, they don't care for wet feet. Beaver dams are a good spot too, they'll walk across on them, but you'll catch more than just cats setting on a dam

I don' know about up north, but down here bobcats run the roads, and I've caught a lot of them at intersectons. They love where ATV trails intersect the main dirt road. One of the leases the members know that when you come to an intersection to keep to the center as "the trapper" has traps on the edges, and I get calls from them when something is in a trap.

In the winter time everything runs roads and trails up here, path of least resistance. I personally wouldn't set on or near any winter maintained roads here, it's asking for issues unless it's your driveway. Your sets will get stolen, plowed over, driven on, or catch someone's dog (dog teams are very popular in places)

If you pick the spots bobcats are likely to cross in good hunting areas (lots of rabbits) or travel corridors (creeks, dry washes, rocky ridges) trapping along roads can be productive. I have several culverts and bridges that have been consistently productive. I have caught quite a few cats within the right of way of paved highways. If the prey and cover is there the cats will cross.