Road traffic in Britain is expected to increase by more than half over a 35-year period, according to new research.

A Department for Transport (DfT) study into future traffic congestion found that the number of vehicles on the road could increase by between 17 and 51 percent in the 35 years from 2015 to 2050.

The growing problem of traffic congestion...

As a result, British drivers are expected to spend more time stuck in tailbacks, with the forecast predicting that the proportion of traffic in congested conditions will rise by between eight and 16 percent.

Journey speeds are expected to suffer, too, with average speeds falling from 34 mph in 2015 to as little as 31 mph. The average journey in 2015 took 17 minutes, but this is expected to increase to 20 minutes by 2050.

Taxi driver protest Uber in London's Whitehall 02.2016

Despite this, the government data shows that the percentage of journeys executed by car will stay roughly the same. In 2015, 79 percent of all journeys used a car, while the projections estimate that 75-81 percent of journeys will involve a car by 2050.

The wide range of the predictions is down to the government’s “scenarios”, on which the predictions are based, although the government says all the projected changes are “fuelled by population growth”.

Traffic on M6 motorway

In one scenario, the projection assumes similar conditions to today, albeit with a larger population, and an assumption that 25 percent of vehicles on the road will be electric by 2050. Another scenario imagines a continuing decline in the number of youngsters learning to drive, while another assumes a high migrant population.

However, the highest growth in traffic is seen in the government’s Shift to Zero-Emission Vehicles scenario, which would see all new vehicles powered purely by electricity in 2040, and 97 percent of all vehicles emitting no tailpipe CO2 by 2050.

Naturally, though, this scenario is expected to reduce carbon dioxide emissions significantly. In this instance, the total emissions could fall by as much as 80 percent, although other scenarios could see a much more modest decrease of around 16 percent.

Close up of a car exhaust

Rather than simply making for interesting reading, though, the forecasts serve a purpose. The government says it will use the forecast to “inform the Department for Transport’s road strategy,” but that the predictions will not be used to influence decisions on local roads, which require more focused analysis.

In its summary, the DfT said there was uncertainty in the results, but that it was vital for the organisation to work out what future demands on the road network might be.

“Understanding future demand for road travel is essential to shape the policies we implement and the investments we make,” the summary read. “However, forecasting future demand is complex and there is significant uncertainty about the extent to which existing trends and relationships will carry on into the future. We will continue to develop our understanding of the uncertainty surrounding the key drivers of demand, the relationship between the drivers and the capability of our models to represent this. And therefore we will review and develop the scenarios used in our strategic forecasts as updated evidence emerges.”