I would start with a smaller shop possibly in the middle of town. Highway drivers are normally passing through unlike local in town traffic. To get them to come to you would take some serious marketing dollars and your pockets are probably not as deep as the dealers and franchises around you. Also, I’ve never considered another shop competition, there’s enough cars for everyone. My competition is the grocery bill, phone bill, electric bill, etc. People only have so much income to spend.
You sound like a smart guy so I don’t doubt your talents. My concern, though, is your lack of shop ownership experience. You need to know about tech productivity and efficiency, parts margin matrix, labor matrix and so on. How to maintain a 50% gross profit in this type of business. How much you pay your techs to maintain at least a 65% labor profit and so on. Without this knowledge, it will be tough to make enough money to stay open. If you already have this knowledge, I would give it a shot but on a smaller scale to start. Again, this is my opinion so take it for what’s it’s worth