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.