When Sweden planned the world’s biggest traffic jam, accidents actually decreased
Switching from left- to right-hand-side driving was a national ordeal
The image has become the darling of internet listicles with titles like “Weird Pics From History.” It shows a mess of cars strewn across a city road — a large crowd gawking at the apparent clumsiness and chaos — on the day Sweden made the switch from driving on the left side of the road to the right. It was a significant and in many ways unpopular undertaking, but contrary to what the snapshot suggests, Dagen H, as the day was called, was a generally smooth and safe success.
The event, held on September 3, 1967, was a long time coming. Sweden’s national legislature, the Riksdag, had considered switching traffic directions at least 10 times since 1927. A referendum held in 1955 may have received low voter turnout, but it nevertheless revealed the surpassing unpopularity of the measure, with 82.9 percent voting to keep traffic moving along the left side of the road, as it had since the 18th century.
But the Riksdag wouldn’t drop the issue. In Sweden, the automobile market was dominated by cars whose steering wheels were on the left , as they are in the United States. This was an advantage when it came to navigating the uneven shoulder of Sweden’s many rough and narrow country roads, but perhaps made head-on collisions more likely, as unfortunate drivers misjudged the placement of their cars on the right edge of the lane. Legislators were particularly concerned about international travel, too, as all of Sweden’s road-connected neighbors in Scandanavia — Norway, Finland, and Denmark — drove on the right side, making border crossings an extra hassle. Popular consensus be damned, the Riksdag finally approved the traffic change in 1963, with a vote of 294 to 50.
Sweden established the Government’s High Traffic Commission to prepare the country for Dagen H, or H-Day (with H standing for Högertrafik, or “right-hand traffic”). There is little surprise the project took years, as numerous countrywide changes were implemented. Buses had to be retrofitted with doors on the right side, and models whose upgrades proved too costly were given to countries like Pakistan and Kenya. Over 10,000 officers were necessary to enforce and monitor the change. Workers installed 360,000 new signs and traffic signals along the right shoulder roads. They remained covered in black plastic, standing by to be unveiled on September 3, 1967.
Sweden heralded Dagen H with a dedicated marketing campaign. A songwriting contest for the occasion yielded a winner titled “Keep to the Right, Svensson,” recorded by a band called the Telstars. The event is also remembered for a memorable feat of graphic design, with its official symbol consisting of an arrow crossing the horizontal bar of the letter H, beginning at the lower left leg and crossing over to the upper right, just as cars were to do. Below the symbol was the relevant date, expressed as “3.9 1967.” It was printed not only on posters and milk cartons, but on novelties like underwear as well.
“Swedish factory and business executives are anticipating a big increase in absenteeism and lateness to-morrow, and for the rest of the week, while the public here adjusts to the new rule of the road,” wrote a Scottish correspondent in Sweden. By September 3, opposition to the traffic change fell to only 30 percent. The Stockholm correspondent remarked on the surprising festivity of the occasion, where at an intersection “crowds started to gathering well before 4 a.m. There were fireworks and singing from an impromptu choir formed by teenagers.”
Dagen H fell on a Sunday. All nonessential traffic, from the early morning hours of 1 to 6 a.m., was prohibited. “Everyone in Stockholm seemed to have set his alarm clock to sound off before dawn,” noted Time magazine about the staggering crowd that gathered to witness the traffic change. “At the stroke of five, loudspeakers blared: ‘Now is the time to change over,’” wrote the reporter. “In a brief but monumental traffic jam, Sweden switched to the right side of the road.”
All was not over in Stockholm, whose ban on nonessential traffic lasted until 3 p.m., at which point came a great influx of traffic, resulting in another demonstration of collective clumsiness. But by day’s end, it became apparent Dagen H was a success, with no fatalities and 157 collisions, consistent with the national average. Drivers remained still cautious on Monday, which saw no fatalities and 125 total accidents, making the day safer than average, with previous Mondays typically seeing around 130 to 198 road accidents nationwide.
There was a dip in traffic deaths and collisions for the first two years, before 1969 brought statistics back to pre–Dagen H levels. Still, even as more cars have gone on the road, the story of Swedish driving has only gotten brighter, with promising long-term trends. In 2016, Sweden saw only 263 traffic deaths, compared to 1,313 in 1966 and 1,262 in 1968 —similar figures lying on each side of Dagen H. It remains difficult to say if Dagen H saved lives, or whether right-side or left-side traffic is more safe in general, but it seems it can’t have done much harm. At least we have the pictures.
