Interstate Network

Here is a short little piece on something that I have just learnt - being of the geometrically and mathematically inclined. I wrote a while back about how I think urban planning is great when the roads are set up in grid patterns and numbered. Well, I have just learnt about the US interstate system which also has logical numbering . 

The basic premise is that numbering increases from west to east (ending in 5) and south to north (ending in 0). Then there is a whole bunch of extra highways in between (odd numbers run N/S and even numbers run W/E), and secondary ones that have three numbers. The US 90 drove past Bozeman, so was our local highway, and here in San Diego we have been using the US 5. Not sure it is possible to drive all of them in one lifetime!

The other interesting tidbit is that on our roadtrip we followed the US 191 for a lot of our drive back from Utah to Bozeman. It is apparently one of the longest three-digit routes. It goes from the Mexican border to the Canadian border. Here endeth todays lesson :)