Speed Limit Recognition

The Problem

• In 2008 there were just under 28,000 casualties in accidents where a speed contributory factor was reported.
• These included 586 fatalities and over 4,000 serious injuries, accounting for 25% of road deaths and 18% of serious injuries.
• More than 4 times as many male drivers had a speed related contributory factor reported than female drivers.

How it Works

Speed limit recognition systems inform the driver the maximum permissible speed for the particular stretch of road the car is on. The systems use information stored in the navigation system as a reference. This is augmented with a camera system that can read speed limit signs, including those displayed on electronic variable speed limit signs on overhead gantries. The camera system output either confirms the figure from the base map, or overrides it where a difference is identified, such as where speed limits have been changed or a temporary limit is in force.

Currently the systems only display the maximum permissible speed and does not interfere with the driver allowing them to ignore the advice. Future developments will allow the system to automatically manage the vehicle speed providing Intelligent Speed Adaptation (ISA). There is also the potential for other safety information to be displayed such as no overtaking, determined from either road signs or markings.

An example of a manufacturer fitting a speed limit recognition system is BMW, and Mercedes will launch a system in the near future.