Carless in Seattle

Selection of posts from my old Carless in Seattle blog

Highways: Regressive or Progressive?

Originally published 21 April 2008

As one commenter, Angus Grieve-Smith, pointed out on my Lexus-Lanes posts, while congestion pricing may appear inequitable or regressive, this says nothing about whether the existing system is regressive or not.

It’s been more than a decade since I earned $26,000 a year, so I thought, instead of talking out my ass, I should dig into the numbers to see if I can prove (or disprove) some of my preconceptions about the financial structure of our current transportation system and how affordable it is for the poor.

Here are the questions I want to answer:

  1. Is our transportation infrastructure regressive already?
  2. How would the addition of a regressive structure like congestion pricing affect the poor versus the wealthy?

It will take me a couple posts to answer these questions, but for all of them, I used 2006 expenditure data from the Bureau of Labor Statistics, broken up by income quintiles, and cut the data a dozen different ways. It’s US data, not just Puget Sound data, so your mileage may vary (ha ha).

Highways: Regressive or Progressive?

So, question 1, is a transportation system reliant on automobiles and highways regressive?

First off, I’m skipping a lot of data, like demographics of these groups, and why I chose expenditures rather than income as the base for my calculations, etc. If you want that, it’s after the jump. If you don’t, this is all you need to know: the five income groups are all equal in size, and represent averages of all the households within the group.

A progressive system would show the poorest consumers paying a smaller or equal percentage of their annual income for transportation than the wealthiest consumers. A regressive system would show the poorest consumers spending a greater percentage of their income on transportation than the wealthiest consumers.


You have to look at both housing (red) and transportation (green) at the same time, since they are opposite sides of the same coin. Housing may be regressive, with the lowest 20% of income earners spending a greater percentage of their money on housing versus the wealthy, but transportation–which means cars–looks progressive.

BLS’s transportation category includes a whole lot of stuff, however, including acquisition of autos, maintenance, gasoline, insurance and mass transit. Even more important, the wealthiest 20% owns more cars than the poorest 20%.

We have to normalize expenditures per vehicle to answer the question “is the entry level cost to our transportation system, a single vehicle, progressive or regressive?” The results are striking.

Take, for example, vehicle acquisition, where you can see the difference between % spent on all vehicles (blue) and % spent on a single vehicle (red):


While the wealthiest 20% spends more on vehicles overall, they own on average, 2.9 cars, while the poorest 20% owns, on average 0.9 cars (64% own or lease at least one vehicle). The poorest 20% spends twice what the wealthiest 40% for the minimum entry cost to our transportation system: the acquisition of a vehicle as a percentage of annual expenditures.


Not only that, but because the poorest 40% of households own fewer cars, they are more likely to have two adults (over 18) who may have to share a car. The wealthiest 60% of Americans have at least one vehicle per adult.


The same goes for all the variable, annual costs of driving a vehicle. Once you buy in, the costs to use our transportation system on a daily basis are regressive as well. Anyway you cut it–by gas, insurance or maintenance for a single vehicle–the poorest Americans pay a far higher percentage of their money on the bare minimum of transportation than the wealthiest do.

This means that our transportation system is regressive.