The right solution is probably to have a two-tone horn, or two "horns". One tone is a normal car horn subject to all the usual rules and restrictions on horns, the other the pedestrian warning noise (e.g. engine hum) that is softer and projected frontward as described, but only when activated by the driver, not on all the time. This second tone would not trigger a ticket the way leaving your regular horn on would. The second tone could be on the same button or stalk or a separate one. Maybe left foot "dimmer switch" position would be good since there is no clutch. It would switch to the regular horn if you're traveling more than the speed determined to be where the tire noise is already loud enough to warn nearby pedestrians. That is, if you're traveling 50 MPH and need to warn a pedestrian of your approach beyond what the tire and wind noise is, you need a real horn, not a soft little engine hum, so if you hit either button the regular horn would sound. I agree that requiring constant low noise is a ridiculous waste of electric power and may be an annoyance from a sound standpoint, but at least for the latter I think the soft tones they are talking about would not, or at least should not if made soft enough, bother the car occupants or anyone more than a few feet in front of the car. Fears of noise pollution are probably overblown.