Abstract
In the first section of this study the speed of 200 cars in 21 Cologne city streets was measured and the characteristics and situation related circumstances were recorded. The evaluation of the data was carried out using a path-analysis. It can be seen that the visible and usable width of the road have the greatest influence on speeds. A similarly clear factor is attributed to stationary traffic. Narrow traffic lanes resulting from reduced widths and parked vehicles have a speed-reducing effect.