The National Highway Traffic Safety Administration has three years to come up with a requirement for equipping quiet hybrid and electric vehicles with sounds so that pedestrians can hear them coming. President Barack Obama signed the bill setting the deadline in January.
With the proliferation of hybrids, advocates for the blind have raised concerns that the vehicles don't produce enough noise to warn pedestrians, particularly at low speeds when they are likely to be operating solely on electricity. Quiet vehicles are a concern not only for the blind, but for anybody traveling on foot or bicycle. A 2009 government study found hybrids are more likely to crash with pedestrians and bicyclists than vehicles with internal combustion engines (see "Hybrids may prompt pedestrians, cyclists to prick up their ears," Dec. 22, 2009).
U.S. Secretary of Transportation Ray LaHood said in a recent blog post that government researchers have begun testing synthetic sounds in advance of the new law. "We're trying to find the right balance between quiet roadways and pedestrian safety," he wrote. Automakers also are trying to get in front of the issue. The electric Nissan Leaf produces an airplane-like whooshing sound at low speeds, as does the M35 hybrid from Nissan's Infiniti brand. The Chevrolet Volt can emit a chirping sound along with flashing lights, but drivers have to activate the alert system. Another example is the Hyundai Sonata hybrid, which makes a sound similar to a gently accelerating gasoline engine.