Speed alert helps drivers maintain a correct speed, avoid speeding, and prevent speed related accidents. Speed Alert informs the driver about the speed limit of the road he/she is using and issues a warning when the driver is about to exceed them.
The system uses a camera to distinguish speed signs on the road and also receives speed limit information from a navigation system. In this way it ensures that even speed limits that are not explicitly visible will be displayed to the driver. Both sets of data are then compared with the speed of the vehicle. If the speed of the vehicle is exceeding the limit a warning is issued. Systems may not issue a warning to the driver when the speed limit is being exceeded as some current systems are voluntary and can be switched off, relying on the driver to respond to the warning. Also, the systems rely on the most up to date digital maps being available.
Other systems use haptic alerts, which harden the accelerator, making it difficult for a driver to depress the gas pedal. Intervention systems go further by reducing the engine throttle, causing the car to decelerate if the car goes above the speed limit.
Commercial vehicles have used these systems for years and are called governors. They cap a car or truck’s speed at a predetermined limit. The main difference with intelligent speed adaptation (ISA) is they can be shut off and also give drivers control over setting the speed limits that activate the alerts and intervention.
One 'non-intelligent' form of ISA is top-speed limiting, where the vehicle is incapable of traveling for prolonged periods over a set top speed. This is easily done with most modern engine management systems since most already have a top speed set at unrealistically high settings of 155 mph.
Almost half of all fatalities to seat-belt wearing drivers occur at impact speeds of 30 mph or less in the United States. However, studies have shown that traveling a mere 3 mph over the posted speed limit doubles the risk of a fatal crash. In a conservative estimate, some 10 percent of U.S. auto fatalities would be avoided if 20 percent of cars had intelligent speed alert.