When comping it out, ideally you want to use similar properties. When that is not possible, you have to assign a value to it based on the sold price difference of other properties with these differences. When all else fails, a best guess is what one eventually resorts to.
Pulling comps for similiar types of 'highway properties' is also tough unless you map out the streets accordingly and then have your agent look on the MLS using specific addresses (very tedious).
If you have a partial view and just a little noise, the resale value shouldn't be effected that much.
It sounds simple, but your insurance against being *stuck* with a home with a significant drawback like this is a very low purchase price. In the future more people will be able to overlook a flaw if the home is priced correctly to factor that in.
Now, let's assume, that by you writing this question, that this is no 'highway in the distance' view.
You will have what is known as a 'unique' property. Much like landlocked homes (no alley access), units over bars, and properties where a Dahmer type character lived.
You'll want to advertise in the back of car magazines (do they still make Motor Trend), the trade journal for on-air traffic reporters, and the Society of Highway Engineers. These people won't force you take the hit that an average buyer will on your price, and you'll feel good about yourself knowing that you have provided a view that these people had only dreamed about!