It's getting dark, you've had a terrible day at work and then, as if to add insult to injury, a puncture happens. What are you going to do about it?
Thousands of people become stranded every year when their tyres are pierced by nails, glass or other sharp objects.
And according to the AA and RAC, fewer people than ever are opting to change a wheel themselves. Most have a useless tyre repair kit, none of which work properly even for those people determined enough to attempt it. These irritating little kits are the reason the RAC has reported a four-fold increase in call-outs for 'puncture, no spare' situations. They were up to a startling 118,000 last year.
Imagine it's you, stuck there under the ever-dimming sky with trucks, vans and cyclists skimming past and peppering your stricken paintwork with stone chips.
You want to get moving, obviously. If the puncture is on the right-hand side of the car you've got no chance unless you want to be hit by a lorry, and if it's on the left you'd have to fit your spare wheel (if you even have one) without being able to see whether an inattentive trucker is about to smash into the back of your car. Both are nightmare scenarios, and you're in for a long wait before your breakdown provider gets to you.
There is a third possibility - that your car is fitted with run-flat tyres. A warning light appears on your dashboard: you've lost pressure in a tyre, so slow down and take it easy. But you can get home, to a garage or to a hotel. Be careful and you can keep driving for at least a few dozen miles before the tyre becomes so damaged that it's dangerous.
You can corner more or less normally, you can brake safely, and as long as you stay below the recommended speed, usually 50mph, the tyre will stay in one piece long enough for you to get where you're going.
The quality and durability of run-flats is improving all the time. The first generation of run-flats were, true enough, rock-hard and ruined the ride of any car they were fitted to. But a controlled demonstration at Bridgestone's European Technical Centre shows a vast improvement on that score. They still aren't quite on a par with fully inflated tyres, but the compromise you make for the sake of that emergency safety net is tiny compared to yesteryear.
Nor are they all that expensive. You might pay less than £15 extra per tyre to upgrade to run-flats according to a quick search on tyre website Blackcircles.com using the extremely common 205/55 R16 measurements.
Now imagine yourself back at that grim, fume-drowned roadside, waiting for the breakdown van to appear while your evening meal goes cold. What would you give to be at home with your family? An arm? A leg? £60? Your choice. When your tyres next need replacing, think carefully about run-flats.