The Price of Quiet Driving - A Noise Study of 35 Passenger Cars

What is the cost of experiencing a quiet driving experience? That question was posed when Swedish automotive magazine Vi Bilägare conducted a thorough measurement of the noise level at different speeds in 35 different passenger cars.

When speaking of noise inside the cabin of the car, there are three main types: road noise, wind noise and engine noise.

The test by Vi Bilägare was conducted on Swedish roads, which may well be the noisiest in the 'developed world'. The rough asphalt used in Sweden is merciless on passenger cars, which are often poorly isolated. The result is pretty fierce road noise - the roughness of the asphalt creates vibrations that, via the wheels, are transported into the chassis, producing a low-frequency road noise. As stated by Vi Bilägare, this type of noise is the most treacherous since its monotonous sound makes drivers tired and dangerous drivers.

Automotive journalists Mikael Schultz and Erik Rönnblom spent a few days in the summer of 2008, measuring the cabin noise in 35 different vehicles. They collected more than 600 sound measurements via a professional decibel meter and then created a noise index.

The test crystallized a clear winner. Luxury car Lexus LS 600h had, by far, the lowest noise rating. It was the quietest car at all speeds measured; 50, 70, 90 and 110 kilometers per hour. Lexus thereby proves that it's possible to drastically reduce the cabin noise - granted, this is a vehicle with a price tag of around 180 000 USD. Hence, quiet, comfortable driving comes at a steep price.

See below the top 10 quietest and loudest vehicles respectively when driven on rough Swedish asphalt. This is just the directional top-line results measured at 90 kilometers per hour. In order to really understand the individual decibel ratings, it is also relevant to look at the tire size and specific tire model used on each car that was part of the test. Merely changing to a different tire size and model can make a big difference in terms of road noise.

Top 10 Quietest Cars

Lexus LS 600h                   65.9 dBA Mercedes S-class               68.7 BMW 5-series                     69.1 Volvo V70                            69.5 Renault Mègane                 69.6 Audi A6                                 69.9 Volvo S80                            70.6 VW Tiguan                          70.7 Toyota Prius                        71.3 VW Passat                           71.4

An interesting finding above is that the Volvo V70 Station Wagon was found to be quieter than the Volvo S80 Sedan - two cars that are built on the exact same technical platform. Traditionally, it has been said that the acoustics of the larger space at the back of a Station Wagon makes it noisier than a Sedan. But as can be seen in this case, that general rule of thumb wasn't valid. Hence, if you really want a versatile Station Wagon with large boot space, yet wish for the car to be quiet, test drive a selection of cars and compare Station Wagons vs. Sedans to see which are noisier.

Top 10 Noisiest Cars

Citroën C1                             77.4 Nissan 350Z                        76.8 Ford Focus/Opel Astra     75.2 Skoda Fabia                         74.5 Toyota Auris                        74.4 Skoda Octavia                     74.1 Kia Cee´d 5d                        74.0 VW Golf                                73.9 Kia Cee´d SW                      73.8 Peugeot 308                         73.7

As can be concluded from the study, larger cars are generally substantially quieter than smaller ones. Driving around in a Citroën C1 with over 77 decibels at 90 km/h must be a rather painful experience. For those who are used to turning up the music to drown out the noise may not pay much attention to it. But it is a fact that increasing numbers of drivers are reacting negatively towards cabin noise, considering noise as a key parameter when buying a car.

The automotive industry should start paying more attention to acoustics to provide a more comfortable driving experience to the masses of people who crave smooth and relaxing car journeys that have them feeling refreshed upon arriving. It doesn't cut it that you have to be wealthy enough to get a Lexus LS 600h in order to enjoy quiet motoring.

Do you agree? Which car do you currently drive - do you find it noisy or quiet? Please, comment below.

If you're on the look-out for a quiet car, also check out our guide to getting a quiet car.

To learn more about cars and sound/noise, get your copy of the Quiet Cars eBook - Your Guide to a Quieter Ride - plus join the Quiet Cars online community.