Granite Geek: The Software That Tries To Improve Our Road Designs

Mar 17, 2015

Life is a highway, and I want to use GIS-based software to design it all night long...
Credit Stanley Zimny via Flickr/CC -

The idea of building a road is pretty straightforward – you build a path and let vehicles go on the path.

The reality is, of course, is way more complicated. How many lanes does the road need, and in which directions? Which signs are necessary – and which are distracting? Does the road make it too hard for vehicles to get through – or can it actually be too easy?

How roads are designed, and how we might design them better, is the topic for the Science Café discussion this month at Killarney’s Irish Pub in Nashua. The moderator is David Brooks, who writes the weekly Granite Geek science column for the Nashua Telegraph and Granite He joined All Things Considered with a preview.

It’s an understatement to say what goes into a road makes a huge difference – where you put stoplights and intersections can slow traffic to a crawl or make it fly by, depending on where those elements are placed.

Absolutely. Like everybody else, I hate my commute, and I know that if only those idiots had done it slightly differently it would be great, and so we figured that would be a terrific topic for a Science Café.

There is a whole host of software out there that are specifically for various kinds of civil engineering and planning, but roads and transportation in particular - names like TransCAD and Synchro, which is my favorite name...

Slightly villainous sounding.

It is, exactly. And planners use this - we're going to have a couple folks from the Nashua Regional Planning Commission, this multi-town body. There are nine regional planning commissions in the state, that basically help out towns with larger-scale planning.

These software programs used to test out different scenarios - they all run off of what's called GIS, and we know that best because it also fuels the maps we use on our smartphones.

It fuels an amazing amount of everything - Geographic Information System is what I believe GIS stands for. It's basically a way to let the real world into software - latitude and longitude markers are the easiest way for me to think of it. When you put down a house, you know that it's in the same place as the underlying layer of the aquifer, and the slope of the land and the type of soils and all that kind of stuff that's important in planning where to put roads.

Ideally you would put a road design through one of these programs and work out the kinks and then you'd have the ideal road design and that's what would go in on the ground. But not every road ends up with its ideal design. Why not?

Well, we're not going to even be talking [at the Science Cafe] about things like money, which is the real complicating factor. But above and beyond that, there are just choices to be made - there's no such thing as the perfect road. For example, a portion of my commute can be on Route 101A down in the Souhegan Valley, and it exists where it is because of where the aquifer line underneath it was, and therefore where the farms were built, and therefore where the dirt roads were put in initially when the first Europeans came out, and before that where the Indians had passed, and where animals travel. Historically it had to be there - it's not like you could pick it up and move it a quarter mile north because it would be more efficient according to the computer. 

Do planners who have this software at their disposal ever snap and develop a God complex? A person of lesser character could get intoxicated with the power of meddling in our lives. Like we’re all part of a game of SimCity and they’re the overlord.

I hadn't thought of that. You mean, like, they'd say, I know this would be a terrible place for a stoplight, but I'm going to recommend it anyway so I can go down and laugh every morning when people back up. Um, I hope not.

[Note: this post originally misidentified the number of regional planning commissions in the state. It has been corrected.]