Commuter Biases and Trial Options

Kari Kohn Kari Kohn

Some of Eric Jaffe’s recent and past posts at The Atlantic Cities blog deal with the intersection of commuter psychology, public transit, and traffic congestion. His recent post points to research suggesting that commuter bias causes people to miscalculate the costs and benefits of different transit options. In such cases, temporary trials of public transit can change commuter perceptions and behavior that enhance the efficiency of the entire transportation system. Policymakers hoping to reduce traffic congestion may find success with this sort of “try before you buy” approach.

According to Jaffe:

…Part of the problem with long commutes is what’s called the “weighting mistake”—overvaluing the extra bedroom you’ll never use, while devaluing the extra 20 minutes to and from work.

What’s happening with the case of car commuters and transit seems to be a similar cognitive bias known as the “focusing illusion.” By focusing too much on the negative aspects of transit, like waiting on the platform, habitual drivers are overlooking the positive ones, like reading on the train. The authors of the new study believe a better understanding of concepts like the “focusing illusion” could help policymakers attract people onto transit modes that already service their city neighborhood. It should, after all, be an easier bias to correct than the weighting mistake, which would require implementing politically unpopular programs like congestion pricing.

One possibility for changing perceptions and behaviors involves offering free or discounted public transport services.  Several studies suggest that such trials can lead to longer-term shifts in commuter behavior, even after the trials end and the impact of “free” wears off.  However, one drawback of this opt-in approach is that those who participate have a “transit rider’s mindset,” which can be a function of the current environment (ex: gasoline costs at time of trial), and those who choose not to participate will never know if their transit perceptions are accurate. Jaffe highlights a study from an upcoming issue of the journal Transport Policy:

…nearly 30 percent of regular car commuters in Boston and Cambridge, Massachusetts, gave up their full-time parking permits immediately after a brief free-transit trial, with most downgrading to an occasional permit and a few making a full switch to transit. About 25 percent had stuck with the change six months later.

…Interestingly, they also found that those people who did not switch became happier with their drive to work after the study, even though nothing about it had changed. Abou-Zeid and Ben-Akiva think this renewed affection might have occurred because drivers could now say they’d thoroughly evaluated their commute options and decided that the car was the way to go. In fact, both groups became happier with their new commute after the study — suggesting this sense of post-investigative ease went both ways.

The work offers some guidelines for implementing similar programs in other cities. For starters, since most switchers had a transit mindset, employers or policy leaders might be wise to survey their employees or residents ahead of time and target the [temporary] free transit program toward those most inclined to a change. They might also wait for the right time to strike: fuel prices were particular high during the M.I.T. trial.

And, in another study from Copenhagen:

The only intervention that had an effect was the free month travel card, which led to a significant increase in commuting by public transport. As expected, the effect was mediated through a change in behavioural intentions rather than a change in perceived constraints. As expected, the effect became weaker when the promotion offer had expired, but an effect was still evident five months later.

Stockholm’s experiment with congestion pricing is another example of the “try before you buy” approach to changing commuter perceptions that does tackle “politically unpopular” congestion pricing.  Commuters had a chance to preview congestion pricing along with expanded bus service during a seven month trial period. Afterwards, citizens voted in a referendum to make the new system permanent.

Bjorn Harsman and John Quigley describe Stockholm’s adoption of congestion pricing in a recent paper. Before holding a referendum on congestion pricing in 2006, the city conducted a trial. For seven months, drivers paid congestion charges upon entering Stockholm’s center. Officials also increased citywide bus service to demonstrate the benefits of the charge to non-drivers. In pretrial polls, the majority of residents opposed the charge. After the trial ended, 52 percent of residents voted in favor of permanent congestion pricing. Firsthand experience with the benefits of the scheme appears to have tipped the scales.

Tile image by Debarshi Ray.

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