Parallel hybrid electric vehicles (HEV) can be classified according to the location of the electric motor with respect to the transmission unit for the internal combustion engine (ICE): they can be pre-transmission or posttransmission parallel hybrid. A split-axle parallel HEV - in which the ICE and electric motor provide propulsion power to different axles - is a sub-type of the post-transmission hybrid, since addition of torque and power from the two power sources occurs after the vehicle's transmission. The term 'through-the-road' (TTR) hybrid is also used for the split-parallel HEV, since power coupling between the ICE and electric motor is not through some mechanical device but through the vehicle itself, its wheels and the road on which it moves. The present work presents torquespeed relationship of the split-parallel hybrid and analyses simulation results of torque profiles and acceleration performance of pre-transmission and post-transmission hybrid configurations, using three different sizes of electric motor. Different operating regions of the pre-trans and post-trans motors are observed, leading to different speed and torque profiles. Although ICE average efficiency in the post-trans hybrid is slightly lower than in the pre-trans hybrid, the post-trans hybrid vehicle has better fuel economy and acceleration performance than the pre-trans hybrid vehicle. © 2016 The Authors, published by EDP Sciences.