Remember when we raved about all-electric Zero Motorcycles but were let down by their lack of noise? (Jay Leno agreed.) Well, it turns out that folks have similar concerns about hybrid and electric cars--especially in places like Japan, where hybrid sales are strong. Because the motors of those vehicles run so quietly in electric mode, they can pose a safety hazard to pedestrians. As a result, noise-making devices like Lotus' "Safe & Sound" (demoed above) could become a required feature on new cars. Or, drivers could just crank up the Loudness.