Estimating ARV For house on a street

[Victoria Funner]

There is a 5 bedroom 3 bath house located on a (not so good) busy street listed for 100k. Directly behind that street is a beautiful A/B class neighborhood with ARV's between 250k and 300k. Not taking anything else into account how much should I reduce my ARV based off the fact that it's on a street and not in a neighborhood? I thought I hit the jackpot! However, I'm a new investor and was told this decreases the ARV considerably. Thoughts?