I cannot resist… I have to tell… when they did it, they had non-stop media coverage, as much as could possibly be done.

An hour or two after traffic switched, TV broadcast from Svinesund, the biggest of the road crossings to Norway, and a major route for road haulage, and a reporter said something like "here we have the driver of a Norwegian 18-wheeler, <name>. Well, <name>, what do think of the big reform?" Norwegian, looking a little dense and speaking slowly: "Uh, what reform?" There was big signage everywhere. The reporter tried dropping a hint, the Norwegian truck driver refused to have noticed any change in the driving rules. Camera showed the very big 18-wheeler. The reporter dropped increasingly clearer hints and looked discomfited, the Norwegian still said "no, what reform, is anything new?" and eventually they cut the interview and switched back to the studio.

Having a non-binding referendum and moving against the 85% vote takes balls. And we're forever greatful that they did. Presumably people thought it would be inconvenient and voted no, while politicians realized the cost of doing it later would be much larger than just ripping the band aid off. At the time, the number of massive motorway crossings and similar was probably nearly zero. Today the cost would be unimaginable. We would have caved in the 70s at the latest, and at a cost many times larger.

Interesting how changing up the side of the road drivers use elevated their attention, resulting in less accidents, until the activity became second nature again.

The relatively smooth changeover saw a temporary reduction in the number of accidents... These initial improvements did not last, however. The number of motor insurance claims returned to "normal" over the next six weeks

Iceland saw a similar effect on "H-dagurinn" when they made the switch (https://en.wikipedia.org/wiki/H-dagurinn):

Traffic accident rates briefly dropped as drivers overcompensated for the increased risk from driving on the unfamiliar side of the road, before returning to the level following the trend prior to the changeover.

In early 2001, my wife and I visited the beautiful country of New Zealand. The travel books told us to be aware that traffic flows opposite from the US. When we collected our rental car in Invercargill, there was a sticker near the steering wheel that read: "To stay alive, drive on the left!".

We had a good laugh and drove away from the airport. We soon discovered that the raised middle finger was international. :)

There is a joke, that in order to facilitate such a change, it should be done in more manageable steps. So on day 1, only the motorcycles switch over to the other side of driving, on day 2 the motor vehicles, and on day 3 the trucks and busses switches over...

One surprising (after we got a ticket..) thing about parking laws in Sweden is that you're also only allowed to park on the right side of the road / with the car in the direction of the traffic. This has the benefit of that when you're leaving the street parking, you are sitting close to the lane and can look behind you for coming cars and only cross one lane. Compared to parking on the "wrong" side, where you're sitting on the opposite side of the lane in your car, having your view of the opposing lane blocked by the parked car in front of you.

As a cyclist I wish we had the same rule where I live. Far too often a car parked on the street will not see me when they try to exit their spot, as it's only when half the front of the car is in the cycle lane they actually can see past the other car.

I was in Sweden then, was only 2yo though so don't remember it, my parents felt the change went smoothly.

Smoother transition than ipv6.

Something interesting is that roads don’t have the same properties if you just drive them the other direction.

It’s not something you will immediately notice by just looking at the road, you have to think of the full picture.

Imagine a fork vs a merge. You have buffer zones for off-ramps. Tight merges. Psychology of drivers. Reaction to signage. All this alters the flow of traffic and create undesired bottlenecks.

In the bigger cities you can still find a few examples of such originally left roads around, with less ideal flow. Usually around tunnels where rework is difficult.

The somewhat hidden (non financial) cost seems to have been giving up on some of the existing public transport services - like trams. The Wikipedia article mentions that briefly towards the end.

When I was trainee in Stockholm in the 1980s most (if not all) escalators in the metro still run such that you had to take the left one.

> Approximately 90 percent of Swedes drove left-hand drive vehicles

This is probably why the adjustment was so smooth.

I know of this one single intersection in northern Stockholm that still enforces left-hand traffic: https://maps.app.goo.gl/uGWr28JUQnEh9cXc6

The "see also" section links to a similar changeover in Okinawa which mentions that a country having more than one traffic direction is in violation of the Geneva convention (on road traffic) https://en.m.wikipedia.org/wiki/Geneva_Convention_on_Road_Tr...

> changing to driving on the right reduced accidents while overtaking, as people already drove left-hand drive vehicles, thereby having a better view of the road ahead

They already used left-hand drive vehicles but rode on the left?? That's just ridiculous and obvious why they switched...

Imagine trying to do this nowadays.

Maybe the world should standardize on:

    Driving on the right
    Speaking English
    The metric system
    The 2024-06-09 date format
    The Celsius scale
    The 24-hour clock

Making everyone speak English should not happen!

We need to understand that the language you are able to think in - limits your thinking.

Some languages have things you cannot translate into English.

These non translateable concepts do not exist in the Western world view point.