We frequently receive inquiries from individuals / companies regarding new devices for traffic safety. This week we have had repeated requests by email and on Twitter, from a correspondent in Italy, to review an invention to automatically limit speeds.

“The new system allows you to control and reduce the speed automatically when you exceed the speed limit on a road or along a sea route. Check the instantaneous speed and compares it with the maximum speed of the road on which you are traveling (possibly multiplied by a correction factor) obtaining information from a navigation system integrated in the system. If the speed is higher, the system can automatically terminate in various ways the acceleration of the vehicle, allowing you to return safely within the limits allowed.”

Speed limiters are not a new idea. However since the discussion has been brought up, here’s the answer for all to see:

Since speeding over the limit is shown to be a primary factor in only about 3-6% of fatal crashes the downside(s) to the idea far outweigh the upside. We do not support this sort of device as it does not solve the underlying issues of driver training and this sort of device removes the ability of a driver to react to various situations such as:

—  The need to accelerate to avoid a crash from behind.

— The necessity to accelerate to complete passing (currently illegal in BC btw if the speed is over the limit).

—  The need to accelerate to move out of the way of an emergency vehicle.

— Drive swiftly in case of emergency (e.g. to a hospital). and many other reasons that drivers might need to exceed the posted limit.  There is a valid legal issue of “defence of necessity” that should permit these and other actions.


As desirable as the goal may be, moving the “number of deaths tends to zero” won’t be addressed by such a device.  Impaired driving and speed too fast for conditions (below the limit) are much more of a problem and not addressed by your device. Further, we believe that removing the power of decision making from drivers is actually in many cases counter intuitive when building a better driving culture with safer roads.
In fact, preventing acceleration could have the unintended consequence of causing more crashes as drivers are become powerless to control their vehicles and avoid dangerous situations.