You can’t go a day without someone in Austin complaining about traffic. We do it on Facebook. The mainstream media does it. Even Governor Perry did it last week. And the most common responses to complaints regarding traffic in Austin are:
“We need more lanes.”
“We need more roads.”
These people are frustrated because Austin appears to be slow to “address the problem” and construct new roadways. With my background in transportation planning, I can tell you that building more roads will not solve the traffic problem. Here’s why.
Building a new freeway: An example from New York
Let’s say you live in New York. It’s rush hour, and you want to go to a hip new restaurant in Queens from your house in Manhattan. You know driving will take an eternity, so you weigh your options.
You could A) ride the subway and avoid traffic; B) wait until later and drive when traffic clears up; or C) decide not to make the trip at all and eat somewhere nearby instead. In determining what to do, you consider how you get there, when to go, or if you go at all. This rationalizing causes something called Triple Convergence, or Induced Demand, and it is at the root of urban transportation behavior.
Ok, so let’s say that NYC builds a beautiful new flyover freeway that goes from your house in Manhattan directly to Queens. What happens when this new road opens?
At first, there is a temporary leveling of cars on the road network as drivers change their old routes to this more direct one. All of a sudden, traffic across the city opens up and balances out, right?
Not so fast: Now, people like you who would have ridden the subway see a faster route and decide it is now more convenient to drive. Hopping in their cars, they quickly increase the traffic load. And the drivers who were going to make those trips at off-peak hours? They now find it convenient enough to make the trip at rush hour. And the people who weren’t sure they’d make smaller trips like shopping, visiting friends, trying a new restaurant, or stopping by the office also decide it’s more convenient enough to hop in their cars.
Now that all of those people have shifted their routes, their modes of transportation, their times, and their travel decisions, the new road capacity is effectively congested, with all roads levels as high as before construction. After so much cost, time, and inconvenience, everyone is dumbfounded by the lack of relief.
The lesson here is that in a growing city, demand will always be greater than capacity. And even in a world with unlimited money, construction workers, and right-of-way, we still would not be able to build ourselves out of congestion. Instead, we’re actually throwing money away on projects that provide us with nothing but additional debt.
More roads, more access, more traffic: The Hays County example
Induced Demand can be compounded when roads open up access to previously remote areas. As we build these new roads, the improved access increases the desirability of the land surrounding those areas. For example, we can look at the proposal that many road advocates currently support: the expansion of State Highway 45, shown below.
This additional capacity would certainly increase travel options from Hays County into Austin, bridging the gaps between the cities and shortening the commute. As a result, demand for housing in northern Hays County will soar, and homebuyers will flock to the county’s low taxes and 15-minute shorter commute!
The reality, however, is quite different. Between induced demand and the overall increase in commuters from the area, there is actually an overall increase in congestion. The additional road, which cost us all quite a lot of money to construct and even more to maintain, will result in more traffic than before the road was constructed.
Solving the Problem
All of this can be distressing to commuters. If new roads and additional lanes will not solve traffic problems, what can we do? The answer, of course, is that there is no single magic bullet. To relieve congestion and reduce travel times, Austin will need to rely on “a thousand small cuts,” so to speak.
In my next post, I’ll take a look 7 simple methods we can implement to improve transportation in Austin.