By taking it for a walk on a main street I mean walking on the sidewalk and not literally in the street, I'm sure everyone knew that is what I meant but just wanted to clarify just encase there were some people who didn't.

Would it be stressful for the dog, even if the dog was use to the sounds of cars and it was taken on a walk in the early morning and at a certain time at night where it wouldn't be busy and there wouldn't be a lot of cars?

It shouldn't be. Just make sure your dog is "friendly". You don't want an aggressive dog walking down main street trying to bite people. The sounds of cars and children shouldn't effect your dog. Just go slow.

Dog owner for 20+ years.

Dogs always get used to walking along a street with cars passing, and it is good for them in one way, but it is not something I do often because I don't like all the exhaust fumes down their lungs. pets question and answers,www.5d2d.com

All dogs should be able to walk along a road though.