Heavier electric cars pose motorway barrier safety risk

The increasing number of heavy electric cars means that the programme to replace steel motorway barriers with concrete should be accelerated in order to negate the potential of crossover accidents believes Britpave, the infrastructure industry association.

The average weight of a petrol or diesel car is 1.5 tonnes whereas electric vehicles usually weigh between 1.8 to 2.2 tonnes due to extra weight of banks of batteries. Existing steel barriers only have to comply with design standards which were tested using 1.5 ton cars. The safety standards for steel barriers are failing to taking into account of the increase weight of electric cars and this could potentially lead to crossover accidents where vehicles crash through central barriers into the path of oncoming traffic.

In 2023, growing safety concerns led the National Highways to commission TRL to undertake a £30,000 study to assess the impact heavier electric vehicles have on crash barriers amid growing safety concerns. The research findings have yet to be published.

In comparison to steel barriers, concrete barriers are able to contain errant 4x4 cars, light vans, buses, coaches and lorries of up to 13.5 tonnes. The high containment level of concrete barriers is key to minimising the risk of that most fatal of motorway accidents: the crossover. In addition, the 50 year design life and minimum need for maintenance removes the need for road workers to be present on dangerous, live motorways replacing damaged steel barriers. The long life also offers superior reductions in whole life costs and carbon.

Recognising the superior robustness, in 2005 the Department for Transport made concrete barriers the default option for motorways where the average annual daily traffic level is 25,000 vehicles per day and where steel barriers need replacing having reached the end of their 20-year life. In 2022, National Highways started a 3 year programme to replace 63 miles of steel barriers with concrete including sections of the M6, M62, M42, M1, M4 and M5. With the increased weight of electric vehicles there is an argument for dual carriageways to have the same crossover safety consideration as motorways.

Joe Quirke, Britpave Chairman said: “Concrete barriers offer unrivalled strength, safety and whole life performance benefits. These benefits are recognised by the Department for Transport and National Highways who have a programme to replace steel barriers with concrete. The increased weight of electric vehicles – for which steel barriers were never designed for – means that that programme should be accelerated and a similar safety programme be considered for dual carriageways.”