Tuesday, September 05, 2006

Going With the Flow

So, maybe it's not a full month. Then again, I'm not really back. I am writing this in an Internet cafe in Ho Chi Minh City, Vietnam.

If you want to study one-piece-flow, and want to see why moving small batches around is better than lugging large ones, HCMC is the perfect place. The streets here have more traffic than anything I've ever seen. There are very few traffic lights, and driving on the right side of the road is sort of a very loose agreement. Also, the most common vehicles are scooters and light motorcycles. There are 30 million scooters in Vietnam, and by the look of it, most of them drive by my hotel each day. (I'll upload some pictures when I get back.) One would expect the result to be total chaos and confusion. It isn't!

Actually, the traffic flows like nothing you've ever seen (unless you've been here, of course). There are two reasons for this. The first is that though the streets are packed with vehicles, each vehicle is small and manouverable. The second reason is that the drivers drive very softly. They look ahead, and when they see any tendency to congestion they just slow down, or speed up, a bit, and steers gently to one side. The traffic flow rarely stops. There are two main causes of congestion: cars and tourists. Neither is nimble enough to move with the flow of the traffic.

You might think this has got nothing to do with software development, but it does. Speaking in general terms, the streets of HCMC are a business system, and the vehicles are goal units. In Gothenburg, where I live (well, the city closest to where I live), there are traffic lights in every street corner. Those lights regulate the traffic flow by creating batches of vehicles. The result is that when there are a lot of cars in the streets, queues build up. In contrast, here in HCMC, the traffic moves all the time. There are comparatively few queues.

In Theory Of Constraints terminology, there is little build-up of inventory in the HCMC traffic system. Value is added all the time (i.e. the vehicles are moving closer to their destination all the time). In agile development terms, the HCMC traffic flow with small vehicles and no traffic lights corresponds to using small stories instead of large use cases, and short iterations instead of long ones.

What it comes down to, is that it is all about the flow, always.


Dav Yaginuma said...

What I liked about Saigon was the utter trust you had to take in crossing the street on foot. Since the traffic never stops, you just have to wade out into the stream of scooters and walk forward at a steady pace, trusting that the drivers will swerve around you as needed. If you try to move to quick, or stop, you cause a breakdown in the flow!

Also, when driving a scooter, making a left turn required crossing into the oncoming traffic of the left lane about half a block before your turn so you could slowly move to the left as you swam upstream.

Anonymous said...

Traffic lights serve a purpose, however. They regulate the flow of traffic to avoid accidents, help the elderly, disabled, or children to cross the road without subjecting them to mortal danger, as well as other trivialities. It is estimated that 31 people die every day in traffic accidents in HCMC (Vietnam News Online, 2006). The death rate (in traffic accidents) for Vietnam is the highest in the region, with around 12700 deaths registered in 11 months in 2005.

I doubt that similar figures would be acceptable in Gothenburg or Sweden in general.