I'm sad to say that except for trucks the majority of noises from highways these days is from tires. I read a rather long article, in the Atlantic I believe. Apparently car weights have been on the rise for 70 years and on top of that the trend for the same weight car is for wider tires. The increasing noise has been a constant pain for highway planners because population density is increasing, traffic is increasing, and noise per car is increasing. Technology for noise abatement is improving, but expensive.

Given that Tesla cars and anything with similar range is likely to be another 1000 pounds heavier than cars in it's class, the prospect for quieter cars is poor.

Stand on a sidewalk sometime and listen. At constant speed or slowing down electric cars vs normal cars are pretty similar, but be careful to compare cars of similar vintage. This is part of the way I think legislation that add noise to electric cars for safety is misguided. Compare a 2018 BMW, Lexus, Acura, and MB vs a Tesla. Any of them could easily hit you before you easily hear them.