Porsche 911 Speedster

Porsche 911 Speedster

There are few better things in this world than hitting an open stretch of highway in a high-performance convertible, with the top-down, the sound of the engine roaring in your ears and the wind in your hair (if you happen to have any left).

However, a new study from St. Louis University School of Medicine and the Ear Institute of Texas has found that the turbulence battering your ears all day, plus any road noise, could actually lead to serious hearing loss. The catch is that it only becomes unsafe if you drive at speeds of 55 mph and up.

Researchers used five different makes and models of car. Sound level measurements in 80 percent of the cars at 55 mph with the top down had maximum sound recordings greater than 85 decibels--a dangerous level if exposure is lasting, according to the National Institute of Occupational Safety and Health. And if you happen to put the boot in and go even faster, the results are even worse.

The five cars used included a 2009 Saturn Sky 2.0 Turbo, 2004 Nissan 350Z, 2001 Porsche 911 Carrera 4, 2005 Saab Aero Convertible, and 2005 Ford Mustang GT Convertible--all favorites here at MotorAuthority.

The finding is that you should drive with the top up if you plan to exceed 55 mph for extended periods of time--and while earplugs may help, they are not an ideal solution as they can block out potentially lifesaving noises such as the sound of a car in your blind spot, a police or ambulance siren or even the voice of a pedestrian.

[Cambridge University Press via TheCarConnection]