Exploratory Analysis of Connected Fully Autonomous Vehicles on the Safety and Efficiency of Road Networks using Microsimulation

The research had set out to explore the effects of the widespread introduction of driverless technology by using publicly available data and assessing the changes it brings to the efficiency and safety of the road network.
ConFAVs were slowly introduced to the network and average vehicle delays and the level of service (LOS) of links observed, followed by a surrogate safety assessment.
Two published behaviour models (Atkins and CoEXist), and a third model (Tested Logic) was created, which accounted for a change in ConFAV behaviour while following another ConFAV. A comparison of the change in the average vehicle delay and the total number of serious conflicts recorded, highlighted that the CoEXist behavioural model had performed the best in three types of junctions and was used to further analyse the case study.
The case study involved 2 small, isolated networks within the Queen Elizabeth Olympic Park Area of London (‘Site A’ was residential and ‘Site B’ was commercial). ‘Site A’ performed well with delays but performed poorly when comparing the number of recorded conflicts against the increasing numbers of ConFAVs. ‘Site B’ showed
limited improvement in LOS and performed poorly in the safety analysis as the number of recorded conflicts increased fourfold in some scenarios.
The results of the case study led to a conclusion that increased numbers of ConFAVs driving in platoons within the network could reduce delays and as a result either maintained the LOS of the chosen route or made it better. The lead vehicle in the platoon was able to anticipate changes in signals and communicate this with the
trailing vehicles, allowing them to perform better at signalised junctions. Platoons also increased network capacity on congested links allowing better performance in the average delays, as observed in Case Study B. However, greater numbers of platoons resulted in larger numbers of rear-end conflicts when a surrogate safety analysis was performed using Time to Collision (TTC) as a parameter. Thus, it was recommended that another method is used to investigate potential conflicts that could recognise and account for platoons.