Early one Sunday morning, half a century ago, Sweden’s motorists pulled off a deft manoeuvre. September 3rd 1967 was H Day, for Högertrafik (“right traffic”) day. The country, like Britain, had driven mostly on the left since the mid-18th century. But that looked untenable by the 1950s. All its Nordic neighbours were righties, making border crossings tricky.
Voters hated the idea of switching: 83% said nej to it in a referendum in 1955. But politicians don’t always feel bound by plebiscites. In 1963 parliament told a commission to prepare for lane-changing. By 1967 catchy pop songs, stickers, slogans and even special underpants reminded Swedes to turn right.
It all went like clockwork. No vehicles were allowed to move before 5am, then everyone swapped. The authorities shifted 360,000 road signs overnight. Kenya and Pakistan received 8,000 redundant Swedish buses, with doors on the left. Studies showed accidents fell immediately after h Day.
There are lessons from this, half a century on. One concerns revealed preferences, or how well people can imagine something routine becoming different. Swedes hugely opposed the idea of new driving habits, yet promptly accepted the changed reality with a shrug. A second lesson: other countries coped just as pragmatically. Iceland switched to the right in 1968, followed by Ghana and Nigeria in the early 1970s. Samoa went over to the left in 2009, aligning itself with nearby Australia.
In a shrinking world, what other sorts of H Day—harmonising habits—are overdue? Anyone who has struggled to recharge a laptop or a phone abroad knows the stupidity of the world having at least 15 slightly different types of plugs and sockets. The same goes for different ways of measuring: let’s all agree to go metric. People now download recipes from global sites, and regularly shop abroad for shoes or dresses. Why should cooks struggle to remember how ounces, grams, half-cups and quarter-pints relate? Or shoppers have to try to calculate how shoe sizes compare?
Getting more aligned could save lives. Need the police? In Malawi dial 997, but in Gabon it’s 1730, in India 100, Pakistan 15, China 110, America 911, Britain 999. At least the EU, that great harmoniser, has a common number: 112 works everywhere, even in Britain, for now.