Tag Archives: traffic

Congestion Tolling at the Supermarket

To help explain why toll lanes might not be the great solution to traffic congestion many believe them to be, Timothy Lee goes to an unexpected place to draw parallels: your local supermarket.

Supermarkets are a good analogy, suggests Lee, because they operate in a free market, are ruthlessly efficient, intensely competitive, and employ ‘lanes’ (checkout queues)… but they don’t use congestion pricing. The reasons why they don’t, he says, can also be applied to traffic congestion:

First, we have strong and sophisticated social norms, cultivated since we were young children, for waiting in lines. This bit of self-organization is extremely important for the smooth functioning of civil society. We see waiting your turn as an obligation we have to one another, and therefore not as an obligation that a supermarket or transportation agency can waive in exchange for a cash payment. I suspect customers would see people using a tolled checkout lane as breaking an implicit social contract.

More importantly, customers would be suspicious that the supermarket was deliberately under-staffing the free lanes to gin up demand for the express ones. […] In the low-margin grocery business, it would be a pretty effective way for a manager to pump up his short-term profits, while the long-term harm to the store’s reputation would be hard […] to quantify.

This latter concern seems particularly relevant to the case of toll roads. The revenue-maximizing pricing schedule is not the same as the congestion-minimizing schedule. An effective congestion-pricing scheme might generate relatively little revenue if people shift their driving to off-peak times (which is the whole point). The operator of a monopolistic toll road will face a constant temptation to boost revenues by limiting throughput on free lanes and jacking up the off-peak toll rates. The widespread voter perception that they’ve “already paid for” many tolled roads through other taxes isn’t exactly right as a matter of fiscal policy, but I think it’s based on a sound intuition: there’s no reason to think the political process will set tolls in a way that’s either fair or economically efficient.

Our Common Navigational Mistakes

Reading how some animals are able to “instinctively solve navigational problems” that baffle us humans, I was reminded of Tom Vanderbilt, author of Traffic, writing on the most common navigational mistakes we all make.

In [a recent study] a number of subjects were asked to estimate the travel time for a northbound versus southbound bird. The majority of respondents believed traveling north from the equator would take longer than the reverse.

What was going on, the authors speculated, was that subjects were supplanting map-based metaphors for the actual experience of travel. “A lifetime of exposure to the metaphoric link between cardinal direction and vertical position,” they write, “may cause people to associate northbound travel with uphill travel.” Or, as they quote Treebeard in Lord of the Rings: The Two Towers: “I always like going south. Somehow… it feels like going downhill.” […]

The north-south imbalance is just one of any number of ways we rearrange objective time and space in our heads. There are the famous examples of geographical distortion, for example, in which people routinely assume that Rome is farther south than Philadelphia or that San Diego is west of Reno (when in both cases the opposite is true). Or take a simple trip into town: Studies have found that people tend to find the inbound trip to be shorter than the outbound trip, while a journey down a street with more intersections will seem to be longer than one with fewer (and not simply because of traffic lights).

Our state of mind on any trip can influence not just our perceptions of time but of geography itself. As Dennis Proffit, et al., write in the wonderfully titled study “Seeing Mountains in Mole Hills,” […] “hills appear steeper when we are fatigued, encumbered by a heavy backpack, out of shape, old and in declining health”—and this is not some vague feeling, but an actual shift in our estimates of degrees of inclination. Transit planners have a rule of thumb that waiting for transit seems to take three times as long as travel itself. And then, looming over everything, is Vierordt’s Law, which, applied to commuting, roughly states: People will mentally lengthen short commutes and shorten long commutes.

If this topic interests you, Vanderbilt writes about such topics on his blog, How We Drive. You may also be interested in a video interview with Vanderbilt that looks like it will be excellent.

How Congestion Pricing and Traffic Jams Help the Environment

When us laymen think of ways to solve traffic congestion we typically think of two ways: congestion pricing to force those who are most price sensitive off the roads and on to public transport (which should be improved using the funds gained through said pricing), and adding capacity to the roads. But do these solutions really help: do congestion charges and additional capacity really affect overall driving habits and are they beneficial for the environment (do they increase public transport use)?

Traffic jams can actually be environmentally beneficial if they turn subways, buses, car pools, bicycles and walking into more-attractive options. […] The traditional solution to traffic congestion is to create additional road capacity. But projects like those almost always end up making the original problem worse because they generate what transportation planners call “induced traffic”: every mile of new, open roadway encourages existing users to make more car trips, lures drivers away from other routes and tempts transit riders to return to their automobiles, with the eventual result that the new roads become at least as clogged as the old roads. […]

In 1999, the Australian researchers Peter Newman and Jeff Kenworthy concluded that “there is no guarantee that congestion pricing will simultaneously improve congestion and sustainability,” and mentioned several ways in which congestion pricing can defy the expectations of its supporters, among them by causing motorists to “drive exactly as they always have if the congestion charge is covered by their firms (e.g., a majority of London’s peak-hour commuters have company cars and perks).”

Some have interpreted David Owen’s column to be anti-congestion charging: I don’t believe he suggests this, primarily because of his final paragraph, describing what he believes is the most effective congestion management program:

A truly effective traffic program for any dense city would impose high fees for all automobile access and public parking while also gradually eliminating automobile lanes (thereby reducing total car traffic volume without eliminating the environmentally beneficial burden of driver frustration and inefficiency) and increasing the capacity and efficiency of public transit.

It isn’t the solution; it’s part of the solution.

Poor Cyclists Key to Safe Roads

Are poor cyclists and a laissez-faire attitude to enforcing road laws on them the key to safer roads? Are those that cycle on the wrong side of the road, pedal on the pavement and rush along one-way streets the wrong way one of the main reasons why the Netherlands has some of the safest roads in the world?

After writer Caleb Crain converted from wayward biker to obedient cyclist (using two simple rules: Bike in such a way that even relatively inattentive drivers can be expected to see you and know what you’re going to do next, and Don’t be annoying to pedestrians) he read the following that made him question his new-found indignation toward bike salmon:

I was therefore interested, and a little chastened, to read in Jeff Mapes’s Pedaling Revolution: How Cyclists Are Changing American Cities, that moral indignation about the adherence of bicyclists to traffic laws is absent from the Netherlands, the utopia of cycling, which has, Mapes reports, “the lowest per-capita vehicle death rate in Europe,” about a third that of the United States. Except for the requirement that bicycles on the road at night have lights, Dutch police do not enforce traffic laws on cyclists. Explains Mapes:

The Dutch don’t see much sense in going after cyclists and walkers when the only people they are putting at risk are themselves. “It’s their choice,” shrugged [Amsterdam top traffic-safety official Jack] Wolters. … The statistics seem to bear him out. … One influential 2003 study, by researchers John Pucher and Lewis Dijkstra, found American cyclists were at least three times as likely to get killed as Dutch cyclists, while American pedestrians faced at least six times the danger of dying.

Traffic Psychology and The Commuters Paradox

There aren’t many people, I believe, who are able to drive and who are not interested in traffic dynamics. Jonah Lehrer, in a recent column for Seed, takes a brief look at traffic psychology; including ‘the commuters paradox’ and the ‘critical density’.

They found that, when people are choosing where to live, they consistently underestimate the pain of a long commute. This leads people to mistakenly believe that the McMansion in the suburbs, with its extra bedroom and sprawling lawn, will make them happier, even though it might force them to drive an additional forty-five minutes to work. It turns out, however, that traffic is torture, and the big house isn’t worth it. According to the calculations of Frey and Stutzer, a person with a one-hour commute has to earn 40 percent more money to be as satisfied with life as someone who walks to the office.

Apparently, the reason we dislike commutes so much is because “the flow of traffic is inherently unpredictable”–once on the roads we are at the mercy of the traffic all around us.

For more information on this topic, William Beaty’s Traffic Waves site is full of interesting theories and observations on traffic ‘physics’. Lehrer suggests Tom Vanderbilt’s Traffic–a book I’ve seen recommended many times.