DfT study finds that CAVs could reduce delays on UK roads


According to a new study by the UK’s Department for Transport (DfT) connected and driverless cars could significantly reduce delays on the country’s road network.

The Research on the Impacts of Connected and Autonomous Vehicles (CAVs) on Traffic Flow report was conducted by the Atkins consultancy on behalf of DfT. The project used PTV’s VISSIM 8 microsimulation computer software package to create virtual models of different parts of the UK road network, including urban roads and a 12-mile (20km) long motorway section. Delays and traffic flow were all shown to improve as the proportion of automated vehicles increased above specific levels. The study demonstrates that driverless cars offer major potential benefits when the proportion of them on the road is higher than the proportion of older, more traditional vehicles. The study is seen by the DfT as being an important first step toward understanding the full range of complex effects of these technologies. It paves the way for further trials and research to help ensure the transition to driverless or automated vehicles is safe and beneficial for all.

The study examined different scenarios, including the level of automation, the proportion of vehicles equipped with the technology, and different automated driving styles.

The main findings of the report concluded that:

• benefits are relatively small on major roads where traditional vehicles outnumbered automated vehicles, but increase as the percentage of driverless cars on the roads increases;

• when measuring peak traffic periods with a maximum of up to 100% of driverless vehicles, the models saw journey times reduced by more than 11% and delays cut by more than 40%;

• benefits are seen on urban roads in peak traffic periods, even with low levels of automated vehicles on roads, benefits included a 12% improvement in delays and a 21% improvement in journey time reliability.

As well as this study, the DfT, along with the UK’s Center for Connected Autonomous Vehicles (C-CAV) is publishing a response to a consultation on insurance for driverless cars. The response details proposals to extend compulsory motor insurance to include the use of automated vehicles. The response aims to establish a model where an insurer would cover both the driver’s use of the vehicle and the driverless vehicle technology itself. The proposals are intended to be taken through the Modern Transport Bill.

“This exciting and extensive study shows that driverless cars could vastly improve the flow of traffic in our towns and cities, offering huge benefits to motorists, including reduced delays and more reliable journey times,” noted UK Transport Minister Johns Hayes. “Driverless cars are just one example of cutting edge technology which could transform the way in which we travel in the future, particularly in providing new opportunities for those with reduced mobility. This study reinforces our belief that these technologies offer major benefits and this government will support their research.”

Share this story:

About Author


Tom has edited Traffic Technology International (TTi) magazine and its Traffic Technology Today website since May 2014. During his time at the title, he has interviewed some of the top transportation chiefs at public agencies around the world as well as CEOs of leading multinationals and ground-breaking start-ups. Tom's earlier career saw him working on some the UK's leading consumer magazine titles. He has a law degree from the London School of Economics (LSE).