Milton Keynes is a new city conceived in the 1960s and built over the past 50 years to become the most successful UK new town with a population of 265,000, which could grow to up to 400,000 over the next 30 years. The outline of the city, based on a US style grid network, is supported by high quality roads and generous parking provision in the city centre. Additionally, complementary segregated cycle and pedestrian networks offer lots of space for walking and cycling. Currently, Milton Keynes is becoming a centre for the demonstration of new transport technologies with several live trials of autonomous vehicles, cooperative intelligent transport systems (C-ITS) and vehicle electrification.
CoEXist use cases in Milton Keynes
This use case is exploring the impact of widespread CAV take-up combined with a plan to re-define the city-centre as a car-free zone. CoExist is assessing traffic flows on the streets surrounding a car free city-centre. The simulation included passenger pick-up and drop-off points which were placed at multiple points around the car free zone.
CAVs obey logical and precise rules of movement and do not respond in a manner which reflects the conventional behaviour of a human driver. Therefore, traditional macroscopic modelling techniques cannot be used for this study.
Current roads and traffic flows are simulated first to provide a ‘reference scenario’. In this model, the city centre is open to all vehicles and the vehicles were given normal non-CAV behaviours. In subsequent models, different pick-up/drop-off configurations are examined alongside different levels of CAV penetration.
This use case:
- evaluated the relative merits of three different approaches to providing pick-up/drop-off facilities for the users of CAV’s.
- analysed how the city of Milton Keynes could be best prepared to tackle the widespread future uptake of autonomous vehicles.
- In comparison with conventional cars, newly introduced vehicles with a low level of automation significantly worsen traffic flow.
- Once a more elaborate generation of CAVs are on the road, traffic flows improve for both conventional vehicles and CAVs.
Three different measures related to parking are being tested:
- “Pick and Drop-Areas”: a greater number of higher levels of automated vehicles can reduce journey delay times by up to 40% in these areas.
- Multi-storey Car Parks: CoExist observes a 50% increase in journey time delays, as large queues are building up around the entrances and exits of the car parks.
- Multi–storey Car Parks with additional lanes: Once additional lanes are introduced in the surrounding streets, the traffic flow improves drastically.
CAV operation at roundabouts (unsignalised intersections)
The use case focuses on traffic performance at the major arterial road intersections in suburban Milton Keynes. Most of these intersections are unsignalized roundabouts. Thus, vehicle behaviour at roundabouts is critical for the overall traffic conditions in the city. These difficult scenarios are an ideal testing ground for how autonomous vehicles might interact within intersection spaces and to evaluate what measures are needed to facilitate the arrival of CAVs.
Based on an initial ‘reference’ case with only conventional vehicles, a small number of CAVs are included in the model and the following measures are taken:
- The introduction of vehicle-to-vehicle communication when merging at intersections
- Introduction of an additional (third) lane on the approach to each intersection.
Once the advanced stage of CAVs are reached, all road traffic participants (both conventional and other CAVs) can benefit from advanced vehicles.