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.