Road database design for velocity profile planning

More than 60% goods- and almost 90% passenger-transportation is realized in Germany by road traffic (G. Weise and W. Durth, 1997). On top of that, because Germany is geographically in the middle of the internal European market, it is used more and more by transit traffic. This general trend leads to overloads of the roads, requires high concentration from drivers and leads in the end to the endangering of the road safety. To face this problem University of Siegen developed a velocity profile-planning module, which supports drivers by using a special strategy taking the road geometry in front of the vehicle into account. Then, the velocity is exclusively controlled depending on road parameters. So in front of a bend, the speed will be reduced in time. Behind the bend, the car can be accelerated again. This strategy is practicable only if the current position of the vehicle and the road parameters are known. The current position of the vehicle can be determined with a GPS (Global Position System) receiver. The road parameters, however, are stored in a database. Because here the curvature of every road point is necessary, it is not enough to represent a road only as an amount of the points like in road databases used in car navigation system. The road must be represented as an amount of different geometrical elements exactly as in road construction planning. The design of this kind of databases is the subject of this contribution.