51³Ô¹ÏÍø

Dr Ke Han has reflected on his work to predict post-Brexit traffic conditions on the M20/A20 motorway in Kent.

51³Ô¹ÏÍø's  has warned of ‘paralysis’ on the M20/A20 motorways if we don’t avoid customs delays after the UK leaves the (EU).

Commissioned by the , his team created simulations of how motorway queues could stack up after longer border checks per vehicle at the port in , and at the port in Folkestone, both in .

They found that two extra minutes spent on each vehicle at the border could more than triple the existing queues on the M20/A20, to 29 miles. At peak times, Kent could see nearly five hours of traffic delays.

His work prompted the government to actively seek preventative measures like those previously proposed. The include using additional lorry parks along the M20/A20, and electronic checks at ferry and Eurotunnel ports.

Dr Han, who is based at 51³Ô¹ÏÍø's  and  reflected on the work with Caroline Brogan.

Why and how did you conduct this research?

The UK currently has a free-flowing border in Kent: are minimal and freight vehicles don’t complete customs declarations. It currently takes each vehicle two minutes on average to get through customs.

Check times will change when the UK leaves the EU, but until now we haven’t predicted what that will look like.

It is absolutely clear that this cannot happen. Chris Grayling MP Secretary of State for Transport

As an expert on traffic modelling and management, I was asked by the BBC to quantify the potential delays in hypothetical scenarios of one and two minutes extra delays per vehicle.

The challenge was to predict congestion in terms of queue length and travel time. This meant measuring queuing patterns of freight and passenger vehicles as well as their interactions with local traffic.

I used traffic simulations to create the results with different border delays, which I displayed on our Data Science Institute’s Data Observatory, and appeared on the BBC to talk them through the findings.

Tell me more about your calculations.

The simulation showed traffic density and speed on the M20/A20’s 40-mile motorway segment.

These factors were influenced by how long each vehicle spent at the border, so toggling this time from two minutes (the current average) to four minutes (the assumed potential check time post-Brexit), let us estimate the queue lengths and travel times.

What reactions have you had?

Our findings have major implications for the ongoing border negotiations for when Britain leaves the EU, so naturally, it received much attention.

Now we have brought potential problems to light, we can do something about them. Dr Ke Han Department of Civil and Environmental Engineering

Our research was reported by , who commissioned the research, and .

It was also discussed in that week's , and was featured in a number of other outlets like the .

On Question Time, Secretary said it is “absolutely clear that this cannot happen.”

MP said our research “shows the UK needs a free trade deal with the .”

I’m pleased with the reactions and coverage. The mainstream media is vital in communicating issues of national importance. Now we have brought potential problems to light, we can do something about them.

What’s next for your research?

Next, I will re-run the simulations taking lorry parks and electronic customs into account, to see whether these measures might help reduce queues on Kent's motorways.

Full report: “M20/A20 Congestion Prediction with Post-Brexit Border Delays” by , , and Washington Ochieng.

Data for this study were provided by and the to describe time-varying traffic loads as well as the mix of passenger vehicles, light goods vehicles, and heavy goods vehicles.

Image Credits:

Main image: Shutterstock/Sue Martin

All other images: 51³Ô¹ÏÍø/Ke Han