Tuesday, 20 September 2011

A commuter's rant

This morning was one of those mornings; when the alarm clock went off, I felt like throwing it against the wall. Instead I turned it off and lay back down so that I could ease into the day. I promptly fell back to sleep and woke with an even bigger start some twenty minutes later. I let my colleagues know that I would be late.

As we know random events cluster – today they clustered at a railway near me!

I caught a later train and as it rolled to a halt at its first port of call, the conductor announced that we would go no further as there had been a crash further up the line. The advice proffered, which I duly took, was to return to the station from which we had just come and follow an alternate route. Half an hour after I had left my local train station I was back there waiting on an overcrowded platform for the next train to Den Haag. As the scheduled departure time came and went without any sign of our train, and the crowd of unhappy commuters continued to swell, it was announced that there was a problem with a switch near one of the main stations on our route. I rang the office and let them know that I would be working from home...

My commute normally consists of a ten to twelve minute walk, a train journey of some 46 minutes and a tram ride of not quite 15 minutes. Most days I can get to work in about 90 minutes. The journey home is less predictable because it starts with a tram journey – tram schedules are not strict – and can take up to, and on the odd occasion more than, two hours (the difference usually made up almost entirely of waiting).

Why don't I drive? Well, I don't have (nor have I ever had) a driver's licence. Besides that pertinent impediment, there are the issues of gridlock, congestion, pollution and carbon emissions. But I will readily admit that if the only problem were gridlock I would without doubt have converted to the car long ago. Travelling by car is generally quicker and much more fault tolerant - if you step into your car 5 minutes late at the end of the day, chances are you will be home 5 minutes later than normal. If you leave the office 5 minutes late on the way to catch a train, your journey home may end up being extended by a half an hour or more.

If even well organised and largely dependable public transport (as the Dutch system surely is) results in significant delays at least a few times a month and the freedom that travel by car offers all too often equates to the freedom to sit idle in a traffic jam, what can we do to keep things moving?

There are a few obvious stop gap measures; teleworking may help somewhat in combating congestion and should be considered a useful tool but its efficacy is limited as teleworking is detrimental to team work. Flexible working hours could reduce pressure on transport systems during peak hours but any potential tends to be nullified by the demands of the rest of our lives (opening hours for crèche, school etc. may not be flexible) and here again, the issues that flexible hours raise when working in a team are not trivial. Carpooling is another option but it shares many of the drawbacks of public transport and can be socially taxing to boot.

Traffic needs to flow, maybe there are answers to be found in queueing theory. Take my journey as sketched above; I tend to leave myself  13 or 14 minutes to get to the station in the morning even though I know it generally takes around 10 minutes to walk the short distance required. I have to build in slack – if I aim at arriving on the platform as the train pulls in, an extra long wait at a traffic light might be the difference between happily catching the train and being left on the platform panting and cursing under my breath as I fumble for my phone, my connection riding into the distance. The greater the potential for variation in my journey to the station the more slack I'm likely to build in to allow for the unforeseen. Hand-offs are expensive.

More frequent trains would alleviate my problem somewhat – I wouldn't be as worried about missing a train if I could catch another less than 5 minutes later. The rail-road has limited capacity however and a large increase in the number of trains is not easily realised – unless the trains were significantly shorter on average (smaller batches). Thereafter cycle cost needs to be considered; the ratio of manpower & material to customer-kilometres would limit the extent to which batch sizes could be reduced.

If we were to remove hand-off and radically minimise batch size, say to one traveller, would we not simply arrive at travel by car? Yes. But. We still need to consider WIP - Work In Progress; allowing your WIP to rise above certain levels will be detrimental to throughput, alternatively; maximising the use of capacity (efficiency) will, after a certain threshold, reduce flow. If you get out on to the motorway on time in the morning you can whiz on through to your destination. If you're that little bit later, the road is chock-a-block and although capacity is being used efficiently (no. of cars per m2 of road), you will not be going anywhere in a hurry.

In short, if we view travel by public transport as the waterfall option (silos, hand-off, long queues, large batches) and travel by car (as we know it) as the chaos or cowboy option, does that offer up any agile solutions to the traffic problems of the 21st century? Possibly. If there were a system put in place to ensure that the capacity of the motorway was never utilised beyond around 70%, the issue of gridlock could be so atomised as to no longer exist. Cars would be allowed onto the motorway via many slipways, managed centrally by a  control system of traffic lights which would monitor and manipulate (motorway) utilisation, queue length (on the slipways) and batch size (entering traffic). In that way the motorway could actively pull traffic as opposed to playing the proverbial gullet, packed so tight that it can only choke...

To complete the agile/lean allegory; there is even evidence that self-organising traffic is the safest, although I must admit that I'm not sure I'd like to be the one testing that hypothesis on a high-speed motorway.

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