Studies suggest that vehicles, driven in electric mode, either hybrid or pure electric vehicles, are considerably quiet and, thus, that they constitute a safety hazard for pedestrians and bicyclists in traffic. It is claimed that such electric vehicles are not acoustically perceived. They only produce tyre/road noise. There is no power unit noise.

The "minimum noise" of vehicles need to be measured with a standard method and legal limit values for such "minimum noise" need to be be established.

Findings (among others see NHTSA Technical Report, September 2009) show that pedestrian and cyclist crashes commonly occur in low speed zones. The results suggest a higher incidence rates for electric vehicles and hybrid electric vehicles, when compared with internal combustion driven vehicles.

The study showed that for vehicles moving slowly,  the electric vehicle was about two times more likely to be involved in a pedestrian accident than internal combustion engine vehicles. A similar trend was found for cyclists, particularly at intersections. Accordingly, in the project special concern is given to noise at speeds below 20 km/h for which the problem is expected be the worst and where not enough data is available.