How do you define “optimal conditions” in a transport sense? The graphic below paints a stark difference in opinion on what constitutes “optimal conditions” for different professions:
Now I’m both an engineer and an economist, so feel I have some insight into the motivation for whoever developed this graphic.
It highlights a very important issue: Engineers tend to measure performance using indicators that measure mobility, whereas economists tend to measure performance using indicators that measure value.
Now don’t get me wrong: I strongly believe that mobility has a value. I write this having just fanged up and down the northern motorway taking some visiting Australian guests to Tawharanui. But it’s not the only thing I value. Indeed, tonight I will take them to Fort Street for dinner at Ima’s.
I accept that what constitutes “optimal conditions” will change depending on the context, and that in some contexts mobility has a very high value. What I can’t fathom is why the transport/traffic profession have developed such simple and inflexible performance indicators to guide their work.
I’m going to say this right now: Level of service tells you *nothing* about what people value. Why? Because it’s measured independently of the costs associated with being able to move freely. We could, for example, enjoy great LOS if we bulldozed the entire city and replaced it all with twenty-lane motorways connecting to vast carparks, with the occasional office building or house dotted amongst the seas of asphalt. But I think it’s obvious that would be a really, really bad outcome for almost everything else that we value.
From an economic perspective, congestion in cities can be seen as a good thing. It’s an indicator that lots of people are using the city in lots of different ways – going to work, travelling to see friends or family, going shopping, visiting sports games or art museums etc. Congestion has costs, of course, but eliminating it entirely would be even more costly.