Opinion: the unwritten rules of driving in the UK

Did you know that baby rats learn table manners from big rats? It’s true. In the Nineties, research with black rats demonstrated that the neatest method of eating pine cones is passed down through rat generations not genetically, but through social imitation. Without the foggiest idea they’re doing so, rat babies get etiquette lessons from their rat elders.

This vital nugget of information resurfaced in my brain as I was being overtaken by an ambulance on a Cornish dual carriageway. (Stick with me on this one, we’ll get there.) So, yeah, there I am, proceeding in an easterly direction along the A30, when I’m passed by an ambulance on blues and twos. The ambulance driver is giving it some. It starts to pull away from me up the road.

And then we reach the bottom of Hamburger Hill. (Not its original name, but there’s been a McDonalds halfway up since the days that McDonalds was a rare sight in Cornwall, so Hamburger Hill it is.) It is a long, steep hill. The ambulance begins to labour and slow – 70, 65, 60mph. I maintain a respectful distance behind... 55, 50, 45mph. Maybe there’s a particularly bulky patient on board. Surrounded by several of his particularly bulky nearest and dearest.

Forty, 35, 30mph. The carriageway widens to three lanes. There is ample space to overtake. It’s going to be many hours before the ambulance reaches the top of the hill. But at the same time... you can’t overtake a lights ’n’ sirens meat-wagon, can you? What if, just as you pass, you suffer a catastrophic tyre blowout, and careen into the central reservation? Imagine the headlines.

Turns out it’s entirely legal to overtake an ambulance on sirens

I’m not the only one being polite. No one’s overtaking. Halfway up Hamburger Hill, there’s now a queue of maybe 50 cars, all doing 15mph behind the ambulance. An Audi A5, clearly unaware of the social situation unfolding, comes barrelling up the outside lane. He reaches the front of the procession, clocks the circumstances, hammers on the brakes and merges sheepishly into the pack.

It’s a) terrible news for my imminent dental appointment, and b) strangely fascinating, a real life Milgram experiment on the side of a Cornish hill.

I’ve since checked the Highway Code. Turns out it’s entirely legal to overtake an ambulance on sirens, provided you do so safely. But it’s not about what’s written in the Highway Code, is it? It’s those unwritten yet binding social laws of the road: when it’s polite to use the horn, and when it’s rude; the exact point you’re required to merge when two lanes of traffic blend into one; occasions you’re morally obliged to wave someone out at a junction, and occasions you’re not. Rules we all know, yet don’t even know we know.

No one’s ever told us this stuff. (At least, they never told me: maybe others talk of little else but ambulance-passing etiquette.) We’ve soaked it up unthinkingly, subconsciously. We are but impressionable little rats, watching the big rats nibbling their pine cones, learning without learning, absorbing without realising.