Wednesday, August 26

Evaluating my personal VMT

Over the weekend, I decided to chart three years worth of daily Vehicle Miles Traveled (VMT) for our Toyota Corolla. We track mileage at each gas fill up, so those were my data points. To be honest, I was slightly disappointed by the results:

The Travels of the Household Corolla

We ended up with an average of 31.7 miles per day. Split into two people, that's a per capita usage of 15.8 MPD. The combined average was a little better when we both commuted by other means (27.6 MPD) than it is when my wife began needing the car for work (32.8 MPD). This is below the national average but not by as much as I expected. I had not anticipated all of the mileage due to trips out of town and moving across the country, hence the sharply spiking graph.

One of the major lessons that I picked up from Tom Vanderbilt's instant classic, Traffic is that every system needs feedback to run efficiently, and this is especially true of the transportation system. We all consider ourselves to be driving at a safe speed, until we pass an electronic traffic sign displaying our actual speed back to us. Drivers will invariably slow down when simply presented with this piece of information. "How's My Driving" stickers on the back of trucks help the trucking industry track risk management through evaluating individual driver performance. Since driving is by nature such a private experience, the lines of communication we usually use for self-evaluation are limited. It's like you're at a party but you have no idea that absolutely nobody is laughing at your jokes. We need feedback.

As I tallied up our VMT totals, it occured to me that modern automobiles could track this data with more precision automatically. What if a chart of daily VMT were printed out or emailed to us on a monthly basis? Would that have any impact on our decisions to use the transportation system? It's also helpful to know where we stand relative to other people, in order to give some context to the raw data. We often think of "keeping up with the Jones" as a negative force, but it can also be a strong catalyst for positive change as well.

This is essentially one of the main components of the smart grid concept. The more accurate and timely feedback energy consumers are presented with, the more likely they are to voluntarily change their behavior in response to this information. What if we had a Smart Transportation system where everyone was aware of their personal VMT in the context of their community?


Stuart said...

Imagine how much more quickly people might change their driving behavior if a VMT user fee bill came in the mail each month!

LH said...

Daniel, an automatic printout of VMT is a fantastic idea. It's a behavioral "nudge," just like metering displays that allow you to see just how much that really long hot shower cost you, and special lights attached to each appliance that glow in proportion to how much electricity they're using (even when they're "off"). It doesn't surprise us economists that when we decouple cost from behavior, we get behavior that is sub-optimal. (Insert your own snarky comment here about the relevance of that truth to our current health care debate as well.)