When people ask me why I moved to New Zealand, I have all sorts of canned answers. Today, I have a very concrete and unique one: because the scale of things here allows thinkers to wrap their heads around complexity at the level of society. American society, especially when you get into urban planning, regulatory law, and interstate systems, dwarfs the common person. Even the very smart common person. Let me be more specific…
I’m fascinated by this kiwi road sign.
You drive here on the left side of the road, so you see this sign all the time. Two discs stacked on a pole and usually found at the tip of an obstruction, such as a curb island separating the left and right sides of the road. What you’re supposed to do is clear, right? Stay to the left of the obstruction. OK, so what about this sign?
This sign, like the one above, serves precisely the same purpose. Why do kiwis need two signs to do the same thing? I set out to see if I could solve the mystery.
About 20 minutes of internet searches led me to NZTA (New Zealand Transportation Authority) pages and a couple of sites for commercial manufacturers of road signs. Along the way, I even learned a thing or two about ISO 9001 (quality management standards) and ISO 14001 (environmental management standards).
A terminology pattern began to emerge. I kept running into terms like ‘level 1 road,’ ‘level 2 road,’ ‘level 3 road.’ Perplexed, I dug further. Why? Because the description on one site for the twin keep-left sign said that it was suitable for level 1 roads, while the larger single keep-left sign was suitable for level 2 — and sometimes level 3 — roads.
Here’s what I found:
Levels of temporary traffic management (TTM)
All state highways are classified as a particular TTM level dependent on the traffic volumes. Four levels of TTM are described within the code and, in increasing order of complexity, these are:
- Level LV – Low Volume Roads (AADT less than 500 vpd)
- Level 1 – Low to Moderate Volume Roads (AADT 500 to 10,000 vpd)
- Level 2 – High Volume Roads (AADT greater than 10,000 vpd)
- Level 3 – High Volume, High Speed Multi-lane Roads, Expressways and Motorways (AADT greater than 10,000 vpd and speed greater than 75 km/h)
It should be noted that all state highways are classified as Level 1 TTM unless shown otherwise on the maps listed.
And where are these roads? Is there a key? Yes. If you’re not familiar with Auckland, this key is simply pretty, but if you live here and have driven enough of its roads, then the key makes flawless sense.
The TTM table above was like the primer for my puzzle. The twin sign is suitable for L1 roads. The single sign, while also suitable for L1 roads, is suitable for L2 roads. There is an even larger version of the single sign that’s suitable for L2-L3 roads. Although I haven’t seen anything explicit to support this, I think it all boils down to visibility, speed of traveler, and night-time lighting. I plan to confirm this with someone at NZTA (yes, you can actually call a bureaucracy in New Zealand and talk to a person who answers questions directly). I also hope that the bureaucrat can answer the single most nagging question for me — who decided that two small stacked signs were even an option? Why not the smaller single sign in every instance where a twin sign is used instead?
I wrote this post because Richard Saul Wurman, sharing a post on Google+, got me thinking about information versus knowledge. I will be the first to agree that access to awesome amounts of information hasn’t made us smarter (how many Wikipedia articles have you read that you are unable only days later to cite or even remember?) or more informed.
My post was to simplify an argument and see if a single data point — one commonly observed sign — could lead, without a terrible amount of effort, to knowledge. Everyone knows how to obey a sign (well, almost everyone). But how many people know why signs are used the way they are, or how they came to be, given their specific and un-creative lots in life. This sort of understanding may seem banal and beneath notice, but it speaks to the value of knowledge, which, after all, is simply the embodiment of understanding the intersection of information points. And their application thereof.
You have to admit, if you’ve got an eye for design, that solving the simplest mysteries is always good mental squat-thrusts for tackling the presumably more complex ones.