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Sri Lanka Traffic by Design

First, put Sri Lanka on your list of places to visit. It’s a beautiful country with pristine beaches, great archeological sites and very welcoming people. If you do visit, we can recommend the driver you should hire to show you around the country.

Second, we're not making fun of drivers or driving in Sri Lanka, we’re in awe of it. In America (or at least in Texas) we tend to live by the phrase “stay in your lane”, sometimes with deadly results in the form of car accidents or road rage. In Sri Lanka, drivers’ concepts of lanes are much more fluid. We know there are serious issues in the country with traffic accidents and fatalities, but we're fascinated that there is an order behind a situation that at first glance looks chaotic.

We traveled by car for 8 days, and realized very early in the trip that there were some rules behind the chaotic lane changes we saw. We're not saying it’s right or legal, or that they're followed everywhere in all cases, but this is what we saw while riding single carriageways (undivided highways).

  1. Honk to let someone know you’re coming around. David (DB): When we rode from the airport to our hotel on arriving, I wondered why everyone was so angry because I heard so much honking. In the U.S. we honk to tell someone they did something wrong. Pari (PK): Here, as in a lot of countries, it’s a way to say, “Look out - coming around.” It is a audible indicator to let everyone know.

  2. Move over and slow down if necessary to allow someone to pass.

  3. Use one of the 5 lanes, even though you only see 2. (We’ll get to this one in a bit.)

Why is this in a design blog? The end users have redesigned the lane structure to meet their needs. This isn't a serious analysis, but with motorcycles, tuk tuks, cars, trucks and buses all sharing a two-lane highway, it's easy to see how drivers would face frustrations. We noticed some practices they followed to alleviate those frustrations. They bend and break the rules, but have established new ones through a loose social contract. It can lead to accidents, but it also works when people play nice.


The Players

To create an interesting, but simple example, we'll stick to the four players above.

If you don't know what a tuk tuk is, or haven't read our discussion about why it's a model of great design, then you should read our post, "Taken with the Tuk Tuk". They're three-wheeled vehicles that don't move as fast as a car, which can be a challenge on the highway. From what we saw, tuk tuks and motorcycles tend to hug the shoulder.


How it typically works in the U.S.

  1. Driver 2 signals and begins their pass.

  2. Driver 1, being the polite sort, allows them to complete the pass.

But this isn't a perfect world...

... and people don't always play well with others.

  1. Driver 2 signals their pass.

  2. Driver 1 protects their lead in the game of life and shuts it down.

If there's oncoming traffic, we might see something like this...


How many lanes do you see?

Two? You haven't been paying attention, have you? Try thinking out of the box.

Four? DB: In the U.S. you might think shoulders are for passing, but I can tell you from experience that it's a ticket-able offense, especially in Louisiana if a deputy happens to see you.

The correct answer is 5!

1 Left Tuk Tuk/Motorcycle lane*

2 Left Car/Truck Lane

3 Middle Passing Lane*

4 Right Car/Truck Lane

5 Right Tuk Tuk/Motorcycle lane*

* Bonus lanes

In addition to the traditional left and right lanes (2 and 4), we have 3 bonus lanes (1, 3 and 5).

Cool, right?

You don't look convinced.


Five? Get outta town!

Ok. We hear where you're coming from. We'll take this slow. By the way, in Sri Lanka, they drive on the left side of the road.

First, we'll look at...

The Middle Passing Lane

  1. Driver 2 comes up from behind Driver 1 and honks, signaling they're about to pass.

  2. Driver 1 moves to the left and the Truck Driver moves to the right, opening up the Middle Passing Lane.

  3. Both slow down if necessary to ensure Driver 2 can complete their pass.

"Big deal," you say. "They're just getting out of the way."

You're a cynic. We appreciate that. But there's more going on here. The signaling with the horn, all cars involved moving out of the way, the lack of ego; we saw this happen consistently.

DB: Not once did I flinch when I saw a car, truck or bus hurtling head-on towards our car as we passed another vehicle. The drivers seemed to know what to do.

The Tuk Tuk/Motorcycle Lane

  1. Driver 1 signals their intention to pass and the Tuk Tuk Driver moves left into the Tuk Tuk/Motorcycle Lane. (Oh, man, I love tuk tuks.)

  2. Driver 2 signals their intention to pass, and Driver 2 and the Truck Driver move to open the Middle Passing Lane.

  3. Driver 2 completes their pass.

Tuk tuks aren't able to keep up with cars on the highway, so it's common to see cars pass them.

But what if?

What if vehicles in the left and right lanes need to pass at the same time? Glad you asked. We'll spare you the play-by-play so you can watch the animation in peace.

The Big Finish

We hear you. You're saying three lanes is odd. Four lanes is even crazier. But five lanes - there's no way they can squeeze another lane in here, right? Well you're wrong. There's plenty of room. There's still another Tuk Tuk/Motorcycle Lane in there.

To clarify, the Tuk Tuk/Motorcycle Lane is there for these vehicles to move of of the way, but you do see motorcycles and tuk tuks pass slower moving cars or other tuk tuks and motorcycles.


Social Contract?

It looks like that's what's going on.

  1. Signal

  2. Don't block a lane change

  3. Stick to the 5 lanes.

Again, we don't want to trivialize the real issues they face in Sri Lanka because of reckless driving, but there are practices drivers have put into place to minimize the risks.

DB: It was the consistency of those practices that I found interesting.

PK: In the world of User Experience, this problem would be considered a "wicked problem". Like a "wicked problem", there are interconnected issues regarding infrastructure, population, and economics among others. Also "wicked problems" do not have a definitive solution. You will only arrive at a solution that best addresses the problems at the present time. It is interesting to see that in this case a solution was organically arrived at that keeps the user's needs at the center.

When looked at through IDEO's (pioneers in design thinking) criteria for successful Human Centered Design, this 5-lane solution could be considered a successful solution.

  1. This is a desirable solution. Drivers are using it today to allow them to navigate the highway more efficiently.

  2. This solution is feasible. Again, this is behavior-based. There are no real technological or economic barriers. Highway lines do not need to be repainted, and horns work great for signaling lane changes.

  3. This is a viable solution. Again, when the rules are followed and drivers are considerate, traffic can flow without incident.

DB: So what's the takeaway? Sometimes there's an underlying structure we can't see - an order behind the chaos. It's easy to dismiss practices as "a mess" or "disorderly" when they're strange to us, but sometimes, a closer look and some thought will reveal the patterns and the logic behind them.

In the end, we all want to navigate life without hurting anyone. We may take different routes and travel at different speeds, but we all want to get to the same place. Just because you can't see the map someone may be using to get there doesn't mean -

PK: You're stretching that metaphor like silly putty.

DB: I was on a roll.

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