A7 motorway. Cruise control on drives at 130 km/h according to the speedometer on your dashboard. However, taking a furtive look at the Waze application that supposedly guides you to your destination, you realize that the latter specifies that you are moving at… 125 km/h. In this context, it is not obvious to determine which indicator shows your real speed.
The explanation is simple. In fact, car manufacturers slightly overestimate the real speed of a vehicle: from 5 km/h to 10 km/h, specifies Julien Cotteverte, Renault communication director, contacted by Tech&Co. A device that means leaving a margin of error for the driver in the event of an unforeseen event.
So if you drive at 70 km/h, your car’s speedometer shows between 75 and 80 km/h. The same goes for a real speed estimated at 130 km/h on the highway, which therefore fluctuates between 135 km/h and 140 km/h on the dashboard.
For its part, Waze, unlike the car speedometer, indicates a speed that is closer to reality because it is calculated using the GPS data from your smartphone. However, the accuracy of the calculation will depend on the received GPS signal. The latter can be modified according to specific road configurations if, for example, your car travels through dense environments surrounded by buildings or takes narrow tunnels or alleys.
In addition, a temporary connection problem or error can also prevent the speed from being displayed at any given time, without the driver realizing it. It is not the case of the speedometer of a car that will simply follow the evolution of the acceleration of the latter.
On the other hand, when driving at a constant speed in an open space (in a straight line at 130 km/h on the highway, for example), Waze is able to calculate a speed close to the real one because the vehicle’s path is stable and, therefore, more easily calculable.
However, it is recommended not to play with fire and to rely on the slight overestimation announced by the counter on your board, so as not to cross the imposed limitations.
Source: BFM TV
