Accidents on urban expressways lead to large external costs due to the process effects of
congestion; and the reduction of its influence is a main objective for traffic management. The
speed difference between the adjacent positions along the road, called speed spatial
inconsistency, is a potential risk factor which is less studied because of data limitation. It may
be one of the substantial causes of crashes on urban expressways. Thanks to the floating
car data (FCD) generated by the global positioning systems (GPS), which are installed in …