One selling point that some use to attract buyers to electrified vehicles is their wonderful silence. In a hybrid electric vehicle [HEV], the internal combustion engine [ICE] only runs when it is needed, either to generate electricity to charge the battery, or for more power during acceleration.
At a stop light or at low speeds, such as backing out of a driveway, an HEV makes almost no sound at all. Plug-In Hybrid Electric Vehicles [PHEV] are even quieter, since they make even less use of the ICE. Finally, Electric Vehicles [EV] are nearly silent, since they have no ICE at all.
Electrified vehicles, being so quiet, are particularly dangerous to pedestrians, who have counted for generations on hearing the typical rumble of an ICE approaching. Without turning to look, our ability to hear and judge the direction of approaching vehicles has been critical to avoiding collisions.
However, with the introduction of HEVs back in the mid-’90s, the elimination of ICE running has circumvented this innate ability. Last year, Toyota introduced a warning sound that will be implemented on all their HEVs to enhance pedestrian awareness:
Aew National Highway Traffic and Safety Institute [NHTSA] law, will be required on all electrified vehicles. The new NHTSA law, introduced in the 2010 Pedestrian Safety Enhancement Act, should take effect by model-year 2016, and will require that all electrified vehicles, including HEVs, PHEVs, and EVs, to have an automatic alert sound whenever the vehicle is “idling,” at a stop, or traveling under 18 mph.
NHTSA estimates that the addition of the “alert system” to existing and new electrified vehicles will be around $30 per vehicle, and might prevent nearly 3,000 pedestrian injuries, or the equivalent of “35 lives saved.”