Britain is facing an unusual crisis: carspreading. Our road vehicles are getting bigger as people buy more and more SUVs of increasing dimensions and weight. At the same time, our streets and parking places remain the same size.

The consequences of this uncontrolled vehicular expansion have become profound. Potholes are being created in greater numbers as our roads are pounded by heavier vehicles; multiple parking spaces are being taken over by single, giant cars; and road accidents are now producing more severe injuries to drivers and passengers of other vehicles. This last issue is of particular concern.

A study by the European Transport Safety Council found that in a collision between a modest-size SUV (sports utility vehicle) weighing 1,600kg and a lighter car weighing 1,300kg, the risk of fatal injury decreases by 50% for the occupants of the heavier car but increases by almost 80% for the occupants of the lighter car. Similarly, pedestrians and cyclists are more likely to be killed if the car that strikes them has a bonnet that is higher off the road than average, a typical feature of an SUV.

The trouble is that sales of these vehicles are booming. In 2024, they accounted for 33% of all registrations, compared with a figure of only 12% a decade earlier. This dramatic change in the use of our roads has led organisations such as the campaign group Clean Cities to call for strict measures to be imposed on car owners. Their argument is straightforward. If a car generates more potholes in our roads, takes up more parking space and poses more danger to pedestrians, cyclists and other car occupants compared with smaller vehicles, then it is only fair that its owner pays more for driving that vehicle.

Paris has already introduced specific parking charges for SUVs. Drivers of these vehicles now have to pay triple the amount of those who drive regular cars. The mayor of London, Sadiq Khan, has indicated that he would support such a scheme for the capital and should be encouraged to pursue the idea with rigour. However, attempts to tackle the problem should not be confined merely to parking. At present, the owners of polluting vehicles have to pay more road tax, based on the carbon dioxide they emit, and drivers of more expensive cars, including electric ones, are also hit with an extra tax.

It may be that these measures will have to be expanded in future, with similar levies being imposed on the owners of SUVs and other vehicles whose sizes exceed specific dimensions.

Avoiding such measures could allow a transport problem that has already reached significant levels to become a major crisis. It is an issue that now needs to be considered as a matter of urgency.