What's the worst traffic jam you've ever been stuck in?

For me it was an interminable stop-start 100-mile crawl along the M6 a few years back.

We had set off from Edinburgh in plenty of time, unusually for us, and you expect the odd hold-up en route, but the nose-to-bumper procession we were caught in from north of Manchester halfway to Birmingham was enough to make you cry. On and on it went, mile after mile, hour after hour.

Occasionally the brake lights of cars ahead would go out and a gap would open up, like a mirage in the desert. Were we moving? Was it over? No, within seconds we would grind to a halt.

Third gear and open road remained tantalisingly out of reach. With hindsight, stopping at Westmoreland services for extra-strong coffee was a mistake, as there was only one outlet for the extra energy. I don't normally use those adjectives while driving, at least not all strung together like that.

If there were tolls on some British roads there would be fewer people using them, just as there are on French tolled motorways. Because of the cost, we would be more careful before jumping in the car. We would ask ourselves if our journey was necessary and whether taking the train might make more sense; as a result, carbon dioxide emissions would go down. For journeys that had to be made by car, we'd be less likely to get mired in traffic and wouldn't arrive frazzled at our friends' weddings shaking with impotent rage and caffeine withdrawal.

Obviously such a policy would work best alongside investment in railways, but we can't wait until we have a futuristic rail network before considering it because there are just too many cars on the road. As a philosopher almost said, hell is other road users.