Transit on Thursday: HOT Enough? Edition

First of all, let's look at the theory behind tolling. Is it safe for us to assume that we've all taken Econ 101? Because there is a pretty obvious application of basic supply and demand curves when it comes to traffic. In this case, the commodity supplied is a space on the road. Drivers are the demand. The natural equilibrium point is commonly known as a traffic jam.

On an un-tolled road, the commodity is essentially free; supply is limited only by the width of the road and the speed at which vehicles can travel. At equilibrium, as many cars as possible will fit into the space available, and that means very low speeds. Unless demand is dramatically over-supplied, this is the natural state of a road.

Rising area populations such as ours are the main driver behind increased demand for more spaces on the road. Increasing supply by widening roads to meet this demand raises that equilibrium point. Unless demand is dramatically over-supplied, you might get relief for a while, but in the end, all you end up with are wider roads that are still congested.

Adding transit capacity certainly helps to mitigate increasing demand by giving people another transportation option, and one that is more efficient at that. But as we're seeing with Metro, transit capacity faces the same limits.

As the GOA report points out, allowing drivers to use roads for "free" fails to account for the consequences of their consumption, such as the space they take up and the pollution they emit. On the other hand, a variable toll, such as those to be used on the Beltway and ICC, puts a price on this commodity and the result of its consumption that reacts to current market conditions. The toll goes up as the number of cars on a road goes up. As a result, the equilibrium point is not dictated by the size of the road, which causes speeds to slow, but by a price, which does not. It's true that estimates show the price of such tolls could reach pretty high levels at peak times. But that just shows us how much of the price of our driving habit we don't pay for.

Theory is nice, but how 'bout a little practice? In places where toll roads have been put in place, such as Southern California and Canada, data shows that they can be effective tools for managing congestion, and, if implemented correctly, with very few downsides. Total vehicle-miles traveled, the metric traffic engineers use to measure road use, go down, delays go down, fuel use goes down, and air pollution (including carbon dioxide) goes down. Meanwhile, in areas where good service is in place, transit use goes up, and significant revenue is also generated. Those who consider it a double-tax, since gas taxes are still levied, fail to recognize that current gas taxes are not only insufficient to cover the cost of externalities like pollution and delay, but according the Federal Highway Administration, they are insufficient even to cover the cost of building roadways. The additional revenue tolls generate can be plowed back into expanded and better transit service, as well as the smaller fixes at interchanges and bottlenecks that can have a dramatic impact on traffic at a much lower cost.

In more ways than one, we've been getting a free ride on our transportation system for far too long. The result is make-or-break situations, such as the recent legislative debacle in Virginia. If people had been paying for the full cost of their road network to begin with, it's unlikely they ever would have been faced with such a dire situation. As officials desperate for a way to "fix" congestion try bold ideas like HOT lanes in more parts of the country, the benefits of assessing more of the true cost of driving will be more widely accepted. And in 50 years, we'd be surprised if any major road remains un-tolled.