2007/11/11

All You Can Drive Roads

The “all-you-can-eat” restaurant is popular in the US and Canada. Pay $14.95 and fill your plate over and over. Surely someone has studied the correlation between girth and frequency of patronizing such establishments, but who needs a science degree to describe the effect?


Free road access has a parallel. Fill your tank – i.e., pay fuel tax, the “all-you-can-drive” $14.95 – then drive what, where, and when you want. Congestion is the analogy to girth. When unlimited desserts are included some people eat six. When road access is free, too many drive in rush hour, on crowded roads, day-after-day. When road use is charged relative to value (higher demand, higher price) people shift their time or mode of travel. They will telework more often, commute at a different time, be more likely to carpool. They may even use transit, bike, or move closer to work.

And if you don’t shift your travel habits, you will enjoy less congested roads. Everyone wins.

No one is happy about congestion, and most of us realize it will be getting a lot worse. We generally admit automotive emissions are harming our cities, our health, and our planet. Less appreciated but easy to understand is that established cities have a hard time to add new travel lanes, that road building costs per lane-mile climb far faster than other costs, that each new lane mile finds as many or more citizens resisting it as clamoring for it.

The compendium of things wrong with adding cars and roads is long, but we still need to move people and goods as much or more than ever. We have a scarce resource: road-surface where and when we want it. The where and when are key.

In the world of how much to drive, fuel tax is a perfect mechanism: correlated, easily collected, hard to evade, somewhat hidden. But in the world of where and when to drive, fuel tax becomes the problem – silent about the difference between high demand and low-demand roads and silent about when fuel is used. But the value of access of many roadways during peak hours is far greater than those same roadways off-peak.

Paying a charge for road use rather than a tax on fuel consumption is the far smarter approach.

We now mostly operate “all-you-can-drive” roads. In fact, once you pay the London or Stockholm daily congestion charge, “all you can drive” still holds for the remainder of the day.

Therein lies the problem with flat fees. They reduce the number of vehicles that enter a cordon, but they do nothing to reduce miles traveled once inside.

The triple problem of road funding, congestion and emissions demands a variable, distance-based scheme for every mile traveled in lieu of the fuel tax. The most suitable technology for that is global navigation satellite systems such as GPS, and that is in development by several companies. There are ways to deploy without capital cost to government and unsightly infrastructure, unlike the current ‘tag-and-beacon’ systems. There are also ways to use this technology with absolute privacy protection.

The technology solution is understood, the economic reasoning is solid, governments are slowly gathering courage, only the switch-over still has a few kinks.

Something to ponder while you’re sitting in traffic.

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