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.