Are electric cars really quieter on the road?

Our testing gear often produces some interesting results when measuring noise isolationI’ve done plenty of very high speeds on Horiba MIRA’s ‘twin horizontal’ straights, but rarely quite like this.
The Bentley Continental GT Speed Hybrid that I recently road tested took me to the far side of 170mph several times, back and forth in opposite directions, all within the bounds of a measured mile, while simultaneously massaging my rather spoiled and considerable posterior.
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