Don't you hate traffic? Part 2

I have a few different loose ends to tie up from the first installment of Don't you hate traffic? .

First, since I've gotten thousands of emails asking about the title of this post, I'll address that first. It's a reference to The Simpsons (clip here) from back when the show was funny. (Yeah, I'm dating myself here.)

Second, how do you deal with privacy issues involved with tolls? If we use EZ-Pass, do we really want Big Brother knowing where you've been driving? I think there's a good way to get around this, which some politicians might not like: Sell EZ-Pass tags the same way we sell pre-paid disposable cell phones. If you buy an "anonymous" pre-paid unit with $100 on it and throw it away when you're done, then you haven't really given up much personal information.

Now finally, let's throw out this assumption that everyone is the same. Different people dislike traffic to varying degrees. Traffic makes me angry and agitated, but other people are in no rush to get anywhere.

So let's say we have a heterogeneous population and roads that aren't sufficient to accommodate everybody. One day I look outside and see 1000 cars on the road, which translates into 2000 units of traffic, using my super-secret traffic grading system.

Presumably, there are some people on the road who really value the road and/or don't particularly mind traffic. Perhaps they're willing to deal with up to 5000 units of traffic at this time. Every single one of them is on the road right now, because after all, there are only 2000 units of traffic out there.

There are also some people who are willing to deal with 3500 units of traffic, some people who can tolerate 2200 units of traffic, etc. and they're all driving now too.

But then there's a guy (call him Marginal Matt) who will only tolerate 2001 units of traffic. He's still driving (since there's only 2000 units) of traffic, but he's getting very little advantage out of having the roads available to him.

Here's the problem: If he would get off the road, there would be a little less traffic for the other 999 people. By deciding to drive, Marginal Matt is creating 2 units of traffic that all of those 999 other drivers has to suffer through and he's only getting 1 unit of advantage to himself.

In other words, he's creating thousands of units of harm and only getting one unit of benefit. Clearly, we need a pricing scheme that gets him off the road.

The optimal toll would balance these two effects. Switching to dollars, if the optimal toll was $10/mile, then there would be much fewer people on the road -- say 600 people instead of 1000. And if the toll is set correctly, then adding that 601st person would create exactly as much economic benefit to him and it would collectively take away from all the existing drivers.

One pleasant aspect of this is that only the people who value the roads the most will use it, and they'll be the ones paying for it. The people who walk to work and then pay an insane city income tax to help pay for roads are getting a raw deal under the current system. Their taxes could be reduced and we could have the drivers pay for the road. The result would be would be less traffic, more business activity (thanks to the lower taxes) and the roads would provide much more value to the residents.

Now I don't know what the optimal toll is, but I know that people do study this sort of thing and have attempted to put a price on traffic.

This system ideally would also end the "need" to subsidize mass transit. It drives me crazy to hear people say that we need to subsidize the subway in NYC since the alternative would be even more nightmarish traffic. When the idea of congestion pricing on roads is suggested as an alternative, people complain that that would increase the price of doing business, which would "get passed on to consumers".

While I don't have the time to delve into all the fallacies embedded in this nonsense, suffice it to say that if we priced roads correctly, a lot of people would take mass transit because it would be much, much cheaper than driving, and in the case of buses, it would be pretty fast (since traffic would be less severe).

In any case, how is it fair that my friend who walks to work has to subsidize the subway? How 'bout charging me for the subway ride that I take to work and charge Marginal Matt a buttload for the amount of congestion he's causing during rush hour?

Don't you hate traffic?

In his book, The Armchair Economist, Steven Landsburg introduced the concept of taxes and fees that generate no revenue. The concept is so ubiquitous that I thought it'd be useful to show an underappreciated example of it.

I work in Midtown Manhattan. If you look out the window on a weekday at 5 pm, you'll see serious traffic congestion. I used to work near Times Square; if you looked out the window there at almost any time, you saw absolutely horrifying traffic. Consider a few facts:

1. People in Manhattan (at least those that can afford to keep a car there or take a cab) tend to have at least a moderate income; many of them are very wealthy and work long hours. Either way, their time is very valuable.

2. Getting to where they're going must also be incredibly valuable. After all, they're willing to sit in ghastly traffic delays to get there. (The traffic is generally not a surprise, so they knew in advance the trade they were making. And if you are surprised by traffic in Times Square, you should be shipped back to New Jersey.)

3. They're charged a very high toll to get where they're going, but the toll is in the form of lost time, frustration, and unpredictability. (Unpredictability translates into lost time if people have to pad their trip time to get to that important meeting.)

4. The roads and traffic lights are paid for from tax receipts. I doubt the gasoline tax and DMV-related fees cover it, so many other taxes are probably used, e.g. income taxes and sales taxes. These taxes generate large deadweight losses.

Right away, I can see that this arrangement has suboptimality oozing out of its orifices. We use inefficient taxes to build very popular roads. The roads are so popular that there are huge “tolls” (time wasted), and the worst part of all is that nobody benefits from those “tolls”. It's a tax that collects no revenue.

Normally, if I pay a $6 tunnel toll, then I lose $6 and the local government gains $6. That can be used to maintain the tunnel, hire more school teachers, get rid of some of the more destructive taxes, or the money can even be refunded equally to all the residents. Even if the government manages to incinerate half the revenue through bureaucrats' pay and mismanagement, we're still $3 better off than we would be if I paid an equivalent toll that consisted of sitting in traffic. (Even if the bureaucracy is wasteful, it would've been wasteful for income tax revenue and toll revenue alike.)

So let's do a quick thought experiment. Imagine that there are a very large number of people in your city and they're all roughly the same in their behavior and preferences. Yes, that's ridiculous, but we can relax that assumption later. This simplified case can give some serious insight into the problem.

Now let's also imagine that there are roads, which are incredibly valuable, but there are not enough roads to accommodate all the people. In other words, they are a scarce resource. This applies to Manhattan and most cities during rush hour, and it probably does not apply to the smaller suburbs of Kalamazoo.

Ok, now under these assumptions, how many people will use the roads at once? We assumed that the use of these roads is very valuable and so at least some people are going to use the roads. Maybe getting to that meeting a mile away is worth $300 and it really only takes $10 of time, fuel, and wear & tear on your car when the roads are empty.

What if the roads aren't empty, but there are a tiny number of cars on the road? In this case, the roads are slightly less valuable. Sure, now there are a few guys you could have an accident with, and you might have to actually yield to another car once in a while. But being able to use the road is still very valuable. So now if you have a $300 meeting to go to and it costs $12 in time and money to drive, you're going to do it.

How many cars are going to be on the road in equilibrium? What will constrain the growth of traffic? The answer is that if everyone has a meeting that's worth $300 to get to, the traffic will keep building until it costs everybody (remember, we're all alike) just about $300 in time, frustration, fuel, wear & tear, and accident risk. Let's say that magic number is 5000 drivers.

So each driver is “paying” $300 to use the roads and nobody else benefits from that $300 “toll”. Each person gets to his $300 meeting and loses $300 in time, frustration, fuel, wear & tear, and accident risk. I have no idea in advance how much fuel costs, how much their time is worth, etc., but I can still say, assuming the roads can't accommodate everybody, that traffic will increase until the total cost of driving is $300 per mile. At that point, nobody else will decide to jump in his car.

So the road does just about zero good. Each driver spends $300 and gets $300 of benefits. No one on “the other end” of the transaction collects the $300.
Actually, it's even worse than that. I only counted costs to the drivers on the road. But there are costs to the people who didn't drive. They (like the drivers) have to deal with air pollution (again, not a big deal in the suburbs of Kalamazoo, but it can be a big problem in city centers) and noise (try sleeping in Manhattan when you can hear a driver who just discovered how his horn works). While we're at it, the pedestrians are now a little less safe.

Finally, taxes probably had to be raised to build and maintain the road. A few businesses on the margin may have gone under as a result, a few other entrepreneurs decided not to launch their new business in this city, and a few businesses still in operation made one fewer batch of widgets since the price of production went up.
What a great deal! We raise taxes, create some economic distortions in the process, build some roads, the drivers get zero benefit from it, and the non-drivers are made slightly worse off!

Now, I'm not anti-roads or anti-driving. On the contrary, I love both those things. When they're implemented properly they can be extremely welfare-enhancing, they can make you feel like a real man, and they make you think that you really have freedom. I just think that there are much more (economically) efficient implementations.

Let's take a first crack at this idealized case, suppose we got rid of whatever inefficient tax was used for getting road money and instead put a $100/mile toll on the use of the roads. (I'm not being very precise about how the tolls are collected, but that's a detail we can work out later.)

I don't know how many people will choose to drive, but I can guarantee that it will be a lot less than before. This time, if there's only one driver on the road, he faces costs of $110 (the toll plus the $10 from before). Getting to your destination is worth $300 so it's a good deal. So more people will join him. But the number of people can't grow to 5000 anymore since then the cost of driving would be a whopping $400 ($100 toll plus $300 of time/fuel/etc.)

So maybe only 4000 people drive. Each person is getting $300 of benefit, paying a $100 toll, and paying an additional $200 in traffic delays/aggravation/fuel. So the drivers still gain no benefit from the road, but the city raised $400,000 in the process. Now we can ditch those inefficient taxes we implemented to maintain the roads. Imagine that: Rationing a scarce resource using the price system actually improved things!

Now I have no idea what the correct toll is and it would almost certainly vary by time of day. ($100/mile in Manhattan rush hour is high but not really as crazy as it sounds.) And if you are worried about poor people not being able to afford to drive, don't be. If you want to help poor people, give them money or cut their taxes. (Incidentally, this toll plan allows you to eliminate job-killing taxes.) Don't try to help poor people by subsidizing their car use. Does anyone actually think that it'd be a bad thing to eliminate NYC's insane income or sales taxes and replace it with a drive-during-rush-hour tax? (I should also mention that any plan that reduces traffic makes it much, much more practical to travel by bus. Currently in Midtown, a Cub Scout troup can run a three-legged race faster than a city bus can drive.)

But this gets to the heart of why people reflexively distrust politicians who propose ideas such as congestion taxes. (Mayor Bloomberg got to find this out first hand.) Few of us are naïve enough to think that a new tax will replace an old tax. If a politician proposes replacing tax A with tax B, it's a good bet he's pushing to create tax B, leave tax A in place, and then spend a whole lot more money. And that's why this plan will reliably be shot down over and over again.

So I really don’t blame voters for opposing congestion pricing on these grounds. But I do hope that the next time you see a traffic jam, you become enraged at the economic waste before your eyes.


Future post: I’ll toss out that assumption that everyone is the same. And how do you deal with privacy issues?