At low speeds, it's not sedan cars that are a problem: even at idle, trucks and large SUVs are very loud, and accelerating from e.g. traffic lights they really

At low speeds, it's not sedan cars that are a problem: even at idle, trucks and large SUVs are very loud, and accelerating from e.g. traffic lights they really roar. For busy city centers, quieting the trucks and buses (and goddam noisy-on-purpose motorcycles!) will make a big difference.