If there was a death on the premises, they are required to disclose it: I believe that all over California the limit is three years.
This can be a teriffic impediment for some people, not so much for others.
Sometimes, the circumstances play an import role.
Traffic is another matter:
There are no disclosures about traffic, even on a busy street.
This would fall on the shoulders of the Buyer and I believe should piggy-back visiting the neighborhood for all the other reasons; meeting your new neighbors, how many kids, trucks being worked on front lawns, crime, etc.
I wouldn't think of buying a home for my family without checking out the neighborhood; how about you?