A method and apparatus are provided for estimating an impedance through a
node at an intersection between roads in a roadway network. The impedance
may be measured in time or distance, for example. Characteristic
information describes at least one feature of the intersecting roads. One
or more pieces of characteristic information may impact the impedance of
traffic through an intersection and are used to estimate the impedance
through the node. Examples of characteristic information are speed
information, road-type, network routing level, intersection angle
information, one-way, and cross traffic turn information. An impedance
factor, or a cost, is assigned to each piece of characteristic
information. The cost may be positive if the characteristic information
adds impedance to the node, or negative if the characteristic information
subtracts impedance from the node.