Incremental Cost of Building Freeways and Exporting Portland’s Road Fees

I would like to explore to issues related to cost of building freeway lanes, the benefits to the transportation system, and who pays.

1) The incremental costs of building out of congestion is inefficient and serves only a small number of people, making the cost per user extremely high.

2) Personally, I rarely sit in traffic and do not need increased freeway capacity. Therefore my payments, including licensing, registration, and gas taxes will go towards building freeway lanes and road capacity that do not serve me. In fact I am subsidizing suburban development.


Too many people driving during a peak time is the reason for traffic congestion. A new freeway lane would only add real capacity during two or three hours per day. How many users is that?

A typical freeway lane will carry approximately 2,100 cars per hour. And since the average vehicle occupancy is 1.2, we’re talking 2,520 people per hour per lane., or approximately 6,000 users. If freeway lanes cost up to $25 million per mile, the incremental cost per user is $4,167 per mile.

At the same time, I rarely sit in traffic congestion. Well sure, I bicycle to work most days, however I do drive, I drive to Salem as a lobbyist, to meetings, conferences, to visit the Oregon Coast, and even sometimes for shopping. However I almost never sit in traffic congestion because of my trip-types. For me, I don’t need the freeways expanded.

Others however do sit in traffic. One solution is to build more roads. However economists using their math realize that existing capacity is being used inefficiently and developed the concept of “congestion pricing.” Pricing is a tool to that puts a premium cost on a limited roadway supply in order to reduced demand in order to alleviate congestion and increase overall efficiency. The pricing would put the expansion costs squarely on all users, but especially these 6,000.

So, is it efficient to build more freeways?

Are urban core folks subsidizing suburban folks?

How does freight play into this picture?

Who can answer my questions?

One response to “Incremental Cost of Building Freeways and Exporting Portland’s Road Fees”

  1. It is my opinion that those that choose to live in the suburbs should pay for the additional costs associated with that lifestyle, including, of course, roads.

    Freight is an altogether different matter, and some effort should be made to seperate it from commuter traffic, either in terms of cost or in terms of actual infrastructure.

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