Is active noise cancellation useful in vehicles?

Question

The cabin noise of vehicles is a large concern in the luxury market. Why haven't any automakers used the same techniques as are employed in active noise cancelling headphones. In these devices a microphone is used as an in-loop sensor to suppress low frequency ($f\lt500\ \text{Hz}$) pressure fluctuations in the enclosed space near the ear.

Why isn't similar technology used in vehicles? What technical improvements are required over the standard vehicle sound system to implement it? Given the increased volume of the system, what differences can be expected between vehicles and headphones?

Answer 1

Some reasons why noise reduction in vehicle cabins is not a standard feature, yet:

• As @Trevor Archibald states, safety is a very good reason. There is still a need to hear some noises from outside the vehicle such as the sirens of emergency vehicles: police, ambulance, fire fighters truck
• Hearing car horns from other drivers is still needed
• The sound of the engine lets people know if the engine is performing as it should
• It's an added cost some people may not want to pay
• People haven't asked for it
• Most people don't object to hearing some noise, as long as it's not intrusive
• Insulating vehicle cabins against noise by using sound proofing materials has suited most peoples needs until now

It has been introduced in a small number of cars: Auto Makers Shush Cars, but these are a bit more expensive than the average car. See also: Cars Go Quiet, Bose Noise Cancelling in Cars

However, introducing electronic noise reduction technology in cars, could reduce the weight of cars by reducing the amount of sound proofing materials used, Harman Quiets the Car

On a different angle, in the 1980s electronic noise cancelling had been used to cancel the engine noise made by heavy vehicles used in inner urban development site to reduce the amount of noise heard by nearby residents.