The road user network is a dynamic, ever-evolving population in which road users interact to share and compete for road space. The advent of autonomous road vehicles (ARVs) will usher in numerous opportunities and challenges in road user dynamics. One of the challenges is whether an ARV population would be able to successfully enter the existing road user space. Previous work demonstrates that successful introduction of ARVs into the road network must consider the evolutionary dynamics of the existing population. This study examines the effect of different spatial parameters as starting conditions for the introduction of a small population of ARVs into a resident population of human-driven vehicles (HDV). The model utilises the concept of evolutionary game theory and uses a square lattice grid with a novel agent mobility approach. The results show that ARV success exhibits significant sensitivity to variations in initial cluster size, position, and travel range. ARVs seem to perform best in fewer, larger clusters with a shorter travel range. This suggests that the best form of early ARV introduction may take the shape of centralised, highly co-operative fleets of local passenger or freight transport.