In the city, most of the noise is from the cars next to you.
The Smart ED has it's own noise generator that makes a really neat futuristic "wheee" when driving under 40 km/h.
The Tesla is near silent. We have low rolling resistance summer tires on right now.
At mid-speeds of 60-80 km/h, the Smart ED is quiet, with a hint of wind noise. Tesla again is more quiet than the Smart.
At highway speeds 100+ km/h, the Smart ED is as loud as any other compact car, similar to my old Ford Focus.
The Tesla is very quiet at high speed, more quiet than our former Mercedes GLK, especially when it's windy out, the Tesla is not troubled by cross winds.