How do I adjust pricing based on proximity to a busy street?

[Andrew Jones]

My wife and I are looking at acquiring our next property and I think we're going to spend a few years occupying a single family home and doing a slow BRRR. Yes a multifamily would make more sense, but we want another kid and this works better with our other goals. Our budget is a little lean for the area (only $350-400k if we don't sell the duplex) which limits our options. I found a property priced at $365k that has had a tough time selling and seen multiple price drops. It's a desirable area near a community college so I figure I can rent out each of the 4 bedrooms to students once updates have been made (or just sell it and roll the money to another property). The neighboring properties range from $389-559k depending on condition, but this is one of a few properties that backs up to one of the busier 4 lane roads in the area.

The big question I have is how to adjust the value of a property based on proximity to a busy road or other undesirable feature?  Is it just a matter of looking up comps on similar streets, a % adjustment?  Any ideas would be appreciated.