drive on the left

Why does Britain drive on the left? When that question came up, I realised I had no idea. I’d been living here for seven years, and I wanted to know more about why things in my second home were the way they were. I thought this would have a simple answer. It did not.

My research kept bringing me to stories that contradicted each other, or repeated the same explanation without a source. Napoleon turned up, which I hadn’t expected at all. There were some clear dates to learn, but trying to connect them into one tidy reason for Britain keeping left was much harder than I’d imagined.

The rule existed before cars

The question goes back further than driving a car. I began by looking at people travelling on foot or horseback, and one explanation I found was about keeping your right hand ready to use a weapon. In that account, travelling on the left meant somebody coming the other way would pass on your right, where your sword hand was. There was also an explanation about getting on and off a horse from the left.

The written rules are easier to pin down. Section 78 of the Highway Act 1835 includes keeping wagons, carts, carriages and animals on the left or near side of the road when meeting other traffic. That gives a documented rule from well before cars, even if it doesn’t settle every story about how people first decided which side to use.

Then I found a story about a pope directing pilgrims travelling to Rome to keep left. Except other versions said he’d told them to keep right, and I couldn’t find documentation that settled it. That was not a particularly helpful answer. The same supposed instruction seemed to explain opposite things, depending on where I looked.

The Napoleon story went round in circles

The explanation I kept seeing was that Napoleon was left-handed, preferred his armies to move or attack from the right, and made the countries he conquered keep right too. Britain resisted invasion and kept left. That is the story as I found it online. I couldn’t find a decent source that established it with authority.

It appeared in articles and YouTube videos again and again. Some didn’t give a source at all, while others pointed to somewhere else repeating the same account without one. It felt like a giant loop. I’d also seen the Napoleon explanation described as a popular myth, which made repeating it as the answer even less satisfying.

I wondered whether there might be a grain of truth somewhere in it, or whether larger carriages and difficulties at borders had helped countries change sides. Those were ideas I was considering, though. I wanted an authoritative source for the Napoleon story, rather than another version of the same story I’d already read.

Countries really have changed sides

Sweden was one of the examples that surprised me. It changed to driving on the right in 1967, That seemed very late to me. The Swedish state museums’ transport history records the change on 3 September that year. Vehicles permitted on the roads stopped, moved carefully to the right and resumed travelling after five in the morning. This was a planned change, not something that belonged only to the distant past.

Britain had considered changing too. A 1994 parliamentary answer confirms that the case had been studied in detail in 1969 and reviewed again in 1992. The later review found little economic benefit, possible harm to road safety and a cost of at least £2 billion. Those are historical findings and a historical estimate, rather than a price for changing sides now.

Cost and safety were the reasons that stood out when I looked at Britain considering the change. Switching sides would be a huge change for people used to keeping left. After researching it, I didn’t think Britain would ever change. That was my opinion, and I was still much less certain about some of the old origin stories than I’d expected to be at the start.

Watch my research into driving on the left.