We live close to the road, we have guineas, the first year was hard because all 6 guineas we had we raised from keets, they all had names and we had strong attachments to them even though they could of cared less about us. We lost two to cars, the love the ditch across the road. Last year our 4 remaining guineas 2 boys 2 girls continued to play across the road, but seemed to have learned about the cars, we didn't loose any, in fact our two hens had 3 clutches of keets each. So by last fall after selling about 20 keets, we had 18 left with our original 3 (we lost one boy, not to the road, but to something) This year we have lost one so far to a car, sadly I kind of look at it like survival of the fittest. Our biggest problem is that they make their nests across the road (even though they will roost in the chicken coop at night) and once the keets hatch, the skunk finds them, almost every time, never notices the hen on the eggs, but the first night the keets are there, we are awakened by the noise and race out there to chase off the skunk. We loose keets everytime, but its very hard to confine those little guys! They can fit through the smallest hole and then the other guineas try to steal them from the mom who is penned up.
I would try the guineas, know you will probably loose some until they figure it out, but I think you should be able to have some without the road being to big of a problem. Some people stop here and stare as the guineas cross the road, like "what is that thing?"