New analysis shows just 3% of new car models sold in the UK have a spare wheel as standard, leading to more drivers being stranded after a puncture.
An RAC review of 313 models – ranging from the smallest superminis to the largest 4x4s – found only eight automatically come with a back-up wheel in the boot.
The breakdown rescue company said this is causing a rise in the number of incidents where drivers need help in the event of an unrepairable flat tyre.
Its patrols went out to nearly 200,000 call-outs last year where drivers had a puncture and no spare wheel, up from 165,000 in 2018.
Many manufacturers have stopped including a spare wheel as standard to reduce the weight of their cars by up to 20kg.
This makes the vehicles more fuel efficient so they adhere to tougher emissions legislation.
Another reason for the decline in spare wheels is that electric vehicles often have battery packs in the place they would be.
The only car models identified as having a spare wheel as standard were the Fiat Tipo, Ford Focus (selected variants), Hyundai Sante Fe (PHEV), Land Rover Defender, Seat Ateca (selected variants), Suzuki Across, Volvo XC90 (not PHEV) and Toyota Land Cruiser.
RAC spokesman Rod Dennis said: “Getting a puncture on a journey has to be one of the most irritating breakdowns for drivers, especially if it’s as a result of hitting one of the plethora of potholes that currently characterise so many of our roads.
“In the past, a driver could have reached for the spare wheel in the boot but this new analysis shows that these are now pretty much a thing of the past, with a miniscule number of new cars sold in the UK coming with one as standard.
“It’s understandable therefore that drivers are increasingly calling on us to help them out of a tight spot, and it’s a trend we fully expect to continue as electric vehicles are even less likely to come with a spare.
“Fortunately, we’re continuing to innovate to ensure our members get the best service possible should they breakdown as a result of a puncture, having just rolled out a four-stud version of our pioneering multi-fit spare wheel, that’s carried by every single one of our patrols.
“In many cases, drivers ordering a new car can still buy a spare wheel – whether that’s a full-size one or the more common lightweight space saver type – as an optional extra.
“This might turn out to be a wise investment if you are one of the many drivers who unfortunately suffers a puncture.”
RAC vans previously only carried five-stud spare wheels, but a four-stud version has been added as they are becoming increasingly common with new cars, particularly smaller ones.
The Society of Motor Manufacturers and Traders, which represents car makers, declined to comment.