This paper analyzes the data obtained from a 60 GHz infrastructure-to-infrastructure millimetre wave channel sounding campaign, carried out in an urban-highway environment in Brno, Czech Republic. The transmitter and the receiver are placed at different heights to emulate a link between a typical base station and a roadside unit while the passing vehicles acted as scatterers. The measured data is processed to determine the Doppler spread which is then analyzed to study the effect of mobile scatterers on the channel. The proposed processing method successfully overcomes the limitations of the measurement setup. A detailed discussion on the latency versus accuracy trade-off of the proposed method is also presented.