Research in Connected and Autonomous Vehicles and associated Intelligent Infrastructure Environment is of vital importance. By enhancing intelligent symbiotic relationship between the two would help improve traffic related problems and road safety.
Traffic related problems such as congestion, travel delays, road safety and air pollution are age old problems which are mainly caused by rise in traffic demand with limited infrastructure. Our research focus on improving these problems by managing the flow of freight transportation which is considered as the backbone of the economy. To improve the handling and transportation of freight goods, previous studies have highlighted methods such as traffic management systems, routing systems and Intelligent Transportation Systems (ITS). But such measures still struggle with ever increasing flow of traffic.
This research tries to analyse the influence of Connected and Autonomous Freight Vehicles (CAV-F) in improving road traffic flow, congestion and travel times. By simulating road traffic at the Dartford-Thurrock Crossing Tunnel, Kent, UK, using PTV Vissim’s traffic simulation model, Connected and Autonomous Freight Vehicles (CAV-F) are driven alongside conventional light goods vehicles, to determine the feasibility of increasing the traffic throughput at the tunnel. The results show that with the use of CAV-F, the overall traffic flow was increased by ~33% (i.e. up to 7,000 vehs/hr) from current flow of ~5,000 vehs/hr. With the reduction in the headway and standstill distance and increase in scope of intelligent connectivity and traffic speed limit, the average congestion and travel time are reduced even at a higher traffic concentration. By analysing the results, it has thus been possible to highlight the benefits to traffic management and road utilisation by introducing CAV-F into our road network, in the long term.
The video shows the comparison of traffic flow at Dartford-Thurrock Crossing, Kent, UK. On the left, the real-world mandatory five closures scenario is simulated to see how these closures affect traffic flow at 5,000 vehicles/hr traffic volume. The simulation on the right shows the simulated scenario where all the conventional freight vehicles are replaced by CAV-F, at 7,000 vehicles/hr traffic volume. We could see that the traffic simulation using CAV-F performed better than the other one even with 40% higher volume of traffic.
Dynamic Gap Generation – Mathematical Model
The study also proposes a novel mathematical model for generating dynamic vehicular gaps by applying dynamic speed changes to allow the platoon of Connected and Autonomous Dangerous Goods Vehicles (CA-DGV), to travel in isolation via the tunnel. This will ensure safety of other road users in line with check-and-allow procedures where by certain DGVs are escorted via a tunnel in isolation for safety of other road users, as ADR regulations and tunnel category.
The model is verified against different road layouts leading to a tunnel in UK, to ensure all possible driving scenarios are considered. The different road layouts are simulated using PTV Vissim traffic simulation software. The results showed that the model works effectively for all given layouts and desired gaps are generated between the platoon of CA-DGV and its preceding and following vehicles, when the speed changes are applied at the reference locations, calculated using the mathematical model.
As an example, the video shows a typical road layout with two junctions joining the main road before the tunnel. Three the platoons of CA-DGV travelling on three road merge as one with appropriate distance between their preceding and following vehicles to travel via a 200 meters long tunnel in isolation.