One of the most extraordinary sights in Canada is the DVP expressway in Toronto. ”œDVP” stands for ”œDon Valley Parkway,” but it is better known among locals as the ”œDon Valley Parking Lot.” Rush hour starts at about 2 in the afternoon, and lasts until well after 7 pm. It can some- times take an hour to get from down- town up to Highway 401, a grand distance of 11 km.

Sitting in traffic on the DVP, Torontonians get a good chance to look at each other’s cars. This may account for the unusual preponder- ance of extremely expensive vehicles on the road. It’s a non-stop parade of BMWs, Mercedes, Lexuses, and Porsches. My rough count suggests that at least one in every four cars is worth over $50,000.

This only serves to accentuate the fundamental perversity of the DVP. One wonders about all these busy stockbrokers and lawyers in their expensive cars. Presumably their time is worth money. What are they doing sit- ting in traffic with the rest of us? How is it that, with all of their wealth, they have not yet managed to organize their lives in such a way as to avoid sitting in traffic for an hour or more each day?

Of course, there is an easy solu- tion to all this. Roads are congested because they are free. If we gave away cheese for free, too many people would eat too much cheese. Similarly, when we give away use of roads, we get too many people driving too much of the time. (In fact, people drive more than they actually need to, in terms of their own preferences. Imagine stand- ing in line at the cheese stall, thinking ”œhalf these people don’t really like cheese, they’re just here because it’s free.” That’s exactly what you should be thinking next time you are caught in a traffic jam.)

Yet strangely, when David Miller brought up the issue of road tolls in the most recent Toronto mayoral elec- tion, people started throwing connip- tion fits. Miller’s camp beat a hasty retreat, and in so doing, allowed the debate to become seriously distorted. In particular, they failed to correct the impression that road tolls would force drivers to pay for something that they are currently getting at no cost. But there is a cost. We pay in the form of lost time. When we impose a road toll, we are simply exchanging time for money: pay $5, get home 20 minutes earlier. I’m sure all those folks in the fancy cars idling on the DVP would be happy to take that trade.

”œWhat about the poor?” comes the inevitable objection. ”œShouldn’t they be able to use the roads too?” But this is deeply muddled. It’s like saying we should combat homelessness by giving everyone in the entire society a free house. The best way to address the transit needs of the poor is to address the transit needs of the poor, not to give everyone in our society free roads.

The only semi-plausible objection to putting electronic tolls on express- ways is that doing so will divert traffic onto secondary roads, which are not designed to handle that sort of volume. This is based on a fallacy, but a relatively subtle one. It is important to remember that the amount of traffic at any given time is not a constant. Every time some- one makes a trip, they calculate the costs and benefits beforehand. One of the costs that they factor in is the amount of time wasted getting to their destination. If they think it will take too long, they may choose to travel off-peak, or else pool together several unique trips into a single run of errands.

This is why planners estimate that, in major cities, there is up to a 30 percent volume of ”œlatent” traffic in the system. Latent traffic consists primarily of people who would like to take a trip at a given time, but have chosen not to because of congestion. Because of this latent traffic, any increase in the carrying capacity of the road network will be instantly absorbed, as the decrease in travel time brings new drivers onto the road. (Hence the saying that building new roads to ease conges- tion is like loosening your belt to cure obesity.)

The flip side of this is more encouraging. It means that any deter- rent to the use of a road, such as decreased capacity or a monetary toll, does not simply divert traffic, it elimi- nates it. A certain percentage of the traffic simply disappears, because the people who don’t really need to be driving stop doing it (leaving more space for everyone else).

We are constantly hearing about how cities need new sources of revenue. Yet the solution is right under our noses. If there’s one thing that cities have an abundance of, it’s congestion. Taxing congestion (not just traffic, but other forms as well) provides not only a stable and independent source of rev- enue, but also the incentive effects of the taxes themselves, which act to improve the quality of urban life. What’s not to like about that?