Yes, 80-something db *is* loud. Freeways can exceed that up close, as do regular railroads near grade crossings (horn) and where trains are accelerating out of yards (e.g. UP, which parallels HSR in North Fresno, northbound from Ashlan) or up grades (not many of consequence in the Valley). If somebody puts houses near freeways or main railroad lines (and rail transit), sound walls are commonly used to reduce the noise level by 5-10 db (3 minimum, which is the smallest change that is usually noticeable). Sound walls would almost certainly be used along HSR in urban areas, too, if the houses are there first and the line is at/above grade.

ANYTHING running at 200+ mph makes a lot of noise, just from the air it's pushing out of the way. Airplanes ain't quiet either, even on approach with the engines near idle. Road noise for uncongested freeways is dominated by aero and tire noise. The general traffic and other noise in an urban area commonly results in ambient noise levels during waking hours in the 60-70 dbA range - mostly from all those cars and trucks (and straight-pipe Harleys, especially on weekends and at 2 AM) running around on the streets. In my generally quiet suburban area, I've measured ambients around 55-65 dbA daytime, and usually in the low 50s at night so the distant freeway noise becomes noticeable), with spikes into the 70s when there's a lot of traffic at a nearby park (especially with motorcycles) or frequent flyovers (bursty, not constant).

A little more context for the number quoted in isolation...