The noise which is generated by a passing vehicle is attributed to tyre-road rolling contact, aerodynamic air turbulence generated by the car’s body (including wipers and mirrors) and finally engine and exhaust noise. These noises vary differently in proportion to a vehicle’s speed. For instance at low speed, engine-exhaust noise is likely to predominate whereas at higher speeds aerodynamic and tyre noises are more likely to predominate.
An electric motor driving an EV at low speeds (including a PHEV operating on all electric power) will generate less noise that a petrol or diesel engine but will generate the same tyre and aerodynamic noises.
EVs will make the air quality of our cities cleaner by eliminating (or significantly reducing in the case of PHEVs) the particulate matter, soot, Carbon Monoxide, NOx, Sulphur Oxide and CO2 emissions associated with fossil fuelled vehicles.
EVs will make the cities quieter and ultimately more peaceful environments to live in while allowing Ireland to become more self sustaining in terms of supplying transport energy from its own wind and ocean clean renewable energy resources.
With this new technology, it has been suggested that EVs may prove too quiet at low speeds and therefore pose a risk to pedestrians and other road users such as cyclists. Consideration is being given to this question within a European context. As the deployment numbers of EVs begin to rise in our cities and as the population has had time to adapt to this new technology, a more robust assessment of the risk posed to the community by low noise vehicles can be made. In the case where the EU does decide to apply future legislation to EVs concerning low speed noise, some manufacturers are equipping their vehicles to be retrofitted or adjusted accordingly to produce appropriate audible warnings at low speed which is unlikely to add significantly to the future cost of EVs.