Because of the adapted resolution and the characteristic of a histogram the objects have to feature minimal extensions tobe surely detected. The two cameras subdivided into searchblocks, here by the minimal width is x= 600mm, for surely detected vehicles. With a minimal height of y= 534mm avehicle has a height of 8 pixel at a distance of140m. With our history threshold this object can be detected. The frequency ofoccurrence (height in pixel) is low at far distances and rises withthe approaching object, at the level boundaries the frequency is adapted with the resolution. With this minimal dimension even bikers can be detected with our system.