Weather conditions dynamic temporary speed limits on Swedish higway

It is a known fact that wet, icy or snow-covered roads do not allow motorists to drive at the maximum speed permitted. The problem is how to inform the driver about temporary risks springing up after the next bend.

After a number of fatal accidents caused by poor weather conditions on a certain part of highway E22 in Blekinge, southern Sweden, the Swedish National Road Administration (SNRA) commissioned ITS Technology to look into the possibility of a new, intelligent warning system.

The solution was to install six ITS traffic meter stations feeding instant information to two RWIS (Road Weather Information System) units on the 20 kilometer distance in question. The RWIS units, acting as endstations, analyse all weather data and determine maximum speeds adapted to actual weather and traffic conditions. Thus, temporary speed limits can be displayed instantly on eight digital warning signs.

Mr. Hans Holmén, SNRA project manager, feel convinced that this ITS Technology solution will be more or less standard in the future. As will it most likely be adapted to other traffic situations, such as, for one, temporary speed limits in school areas.