Nissan LEAF: Approaching Vehicle Sound for Pedestrians

Media, Nissan shareholders, government officials, analysts and some of the first customers to place reservations for electric vehicles Nissan LEAF will get the chance to experience the benefits of this practical, affordable and fun to drive all-electric car when they get behind the wheel of the first production test units.

Nissan LEAF, is a ‘new car’ in every sense of the word and redefines the driving experience, setting new standards in handling, acceleration and comfort in its class. Nissan LEAF officially goes on sale beginning in December.

Since the 100% electric, zero-emission concept vehicle was unveiled last August at the grand opening of the new Nissan Global Headquarters, the company has been continually refining Nissan LEAF for the October start of production.

Among the enhancements to the test units is the "Approaching Vehicle Sound for Pedestrians" system, which also will be used in the Nissan Fuga hybrid, slated for sale in fall 2010.

The system makes it easy for those outside to hear the vehicle approaching, but the sounds do not distract the driver and passengers inside. Thus, the needs of pedestrian safety, as well as driver and passenger comfort, are met. The sound system is the first of its type to be introduced by an automaker.

Nissan believes the 100 percent electric Nissan LEAF with lithium ion batteries has the potential to be the transformative beginning of a new approach to personal transportation. No tailpipe emissions from this global vehicle mean no CO2 or other gases released into the atmosphere.

In addition to reducing air pollution, Nissan LEAF and other electric vehicles (EVs) reduce noise pollution, making them transformative in yet another way. Unlike their gasoline-powered cars, EVs and hybrids run quietly. Today’s noisy traffic corridors have the potential to possess an almost serene ambience if populated with cars and trucks that are quieter.

While silence is golden, it does present practical challenges. In response to public concern that quiet electric vehicles and hybrids can surprise pedestrians and the visually impaired as they approach, Nissan has developed a set of distinctive sounds that will come standard with Nissan LEAF to ensure a positive experience for drivers, passengers and pedestrians alike.

In developing the sound system, Nissan studied behavioral research of the visually impaired and worked with cognitive and acoustic psychologists. After looking at applied original technology developed to reduce vehicle noise and conducting tests in Japan and abroad, the Approaching Vehicle Sound for Pedestrians system was created.

The sine-wave sound system sweeps from 2.5kHz at the high end to a low of 600Hz, an easily audible range across age groups. Nissan worked to avoid a sound range that would add unnecessary noise to the environment (around 1,000Hz).

Depending on the speed and status (accelerating or decelerating) of Nissan LEAF, the sound system will make sweeping, high-low sounds. For instance, when Nissan LEAF is started, the sound will be louder, so a visually impaired person would be aware that a nearby car was beginning operations. And when a car is in reverse, the system will generate an intermittent sound. The sound system ceases operation when Nissan LEAF tops 30km/h and enters a sound range where regular road noise is high. It engages again as Nissan LEAF slows to under 25km/h.

The system is controlled through a computer and synthesizer in the dash panel, and the sound is delivered through a speaker in the engine compartment. A switch inside the vehicle can turn off sounds temporarily. The system automatically resets to "On" at the next ignition cycle.

Nissan LEAF will be on sale in Japan, the United States, Portugal and the Netherlands starting in December and in the United Kingdom and Ireland starting February 2011. Nissan plans to begin mass marketing Nissan LEAF in 2012.

Production will start in October at the Oppama plant in Japan. The second half of 2012 will see production at the Smyrna, Tenn., plant in the U.S., followed by production in the UK at the Sunderland plant in 2013. Annual Nissan LEAF production for Oppama is 50,000 units.

The Lithium-ion battery that powers Nissan LEAF will be produced by Nissan’s joint-venture with NEC, AESC (Automotive Energy Supply Company). Originally planned annual battery production capacity at AESC was 65,000 units including 54,000 units for electric cars. However, AESC plans to increase annual battery production capacity for EV to 90,000 units by 2011, foreseeing an upward trend in future demand.

The Approaching Vehicle Sound for Pedestrians system conforms to guidelines set by Japan’s Ministry of Land, Infrastructure and Transport in its report, "Measures for dealing with the silence of hybrids and similar cars," released in January.