Note: Links to all of four Japan factory tour posts and the various lessons from those tours can be found here.
While traveling to Japan a few days ago, a surprisingly easy trip by the way, I was reminded of the power of flow.
First off, just a couple block from my house, our small town is just wrapping up construction of one of the first roundabouts in our county. The intersection had been a mess, with offset streets and a main road that starts with the exit from the Pacific Coast Highway. There's just no way to create an orderly intersection with traditional stop signs, and traffic was continually backing up in one direction or another. I've long been a fan of roundabouts, especially after visiting Italy a couple years ago (which I blogged about here). It may appear chaotic at times, and traffic may even appear to move slower, but it flows continuously. You end up getting there faster, bottlenecks are accommodated automatically... you get the picture.
This new roundabout has already dramatically changed traffic patterns as people intentionally use that intersection now because it is so much more efficient. The impact of continous flow is powerful. The one downside is that the average age in my town is about 80, literally, and traffic circles require quick decisions on yields. A trick I learned while living in Boston, home of some of the most notorious multi-lane circles in the U.S., is to always look straight ahead and barge forward. If you look to the side then others believe you may have seen them, and they'll then take the bold initiative. It works. Perhaps not always advisable, but it works.
The second reminder occurred at the San Francisco airport. I had to change planes from United's domestic terminal to the United international terminal, which are literally adjacent. Keep in mind that the international terminal was just renovated at some obscene cost. I arrived at gate 88, and my Tokyo flight left from 92... just down the short hall between the two terminals, right? Not quite. I walked the couple hundred feet down the hall and arrived at a sign that said I was leaving the secure area and would have to go back through security to get to my gate. I was close enough that I could see my gate a bit further down the hall. The walls were contiguous. There was no way in or out for potential bad guys. But to walk that additional fifty feet or so I would leave security then have to rejoin a rather massive security line coming in from the outside.
I returned to where I had seen a "bus to international terminal" sign and joined the line. Twenty minutes later I was being herded down a couple flights of steps to a small bus. When full the doors closed and we drove... about 100 feet... to the international terminal. The fun didn't end there. We got out and were herded over to an elevator that held eight people. Eight at a time (obviously I was near the end...) we waited, entered, and rode upstairs. The elevator door opened and facing me was the hallway I had just walked down earlier.
What was the reason? By using the bus I didn't have to go back through security, so obviously there were no concerns about domestic versus international security zones. It would seem that a modest expense of about $1,000 (ok, $25,000 in San Francisco) would have paid for the thirty or forty foot section of additional secure wall needed to complete the secure hallway. Instead a couple buses were bought, drivers hired, elevators strained, and nerves frayed.
So as a final lesson, let flow flow. Don't feel like it has to be managed with signals. And whatever you do, don't force flow into batches.