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HELPING NEW YORK CITY DRIVERS AVOID GETTING BOOTED: Behaviorally informed warning emails to reduce unpaid parking ticket debt | 3
“EnforcementWarning” to the more neutral sounding “NYCparking” address may lower drivers’ aversion
to opening what previously sounded like a harsh email. Indeed, a previous parking ticket experiment, run
by the BDT, with a similar population of NYC ticketholders found that a softer, non-blaming tone on parking
ticket envelopes motivated drivers with expensive tickets to address their parking debt.
To improve upon the original email subject line, “Take Action Now To Avoid Booting or Towing,” we
developed three other subject lines—one of which was action-based, “Pay now to avoid towing,” another
which highlighted risk, “Your vehicle is at risk for towing,” and a final one, which both highlighted risk and
was personalized with drivers’ plate number—“Action Needed: Plate CJK876 at risk for towing.” To gain
insight into which subject line might produce the best email open rate, the BDT performed an online test
using Amazon’s Mechanical Turk (MTurk), a crowdsourcing platform that allowed us test the eectiveness
of our prototypes online with 6,000 remotely located people. The results did not clearly show one subject
line to be more eective at increasing open rates. After discussion with the DOF, we decided to use
the subject line “Your vehicle is at risk for booting” for our pilot with NYC drivers because it succinctly
highlighted the most likely initial outcome for drivers—booting (not towing)—if drivers did not address their
tickets. The piloted subject line also reduced the ambiguity of the original subject line, which suggested
drivers could be booted or towed.
Encouraging Recipients to Act Promptly
Because drivers need to understand the boot warning email before they can act, the redesign sought
to limit the complexity of the language and cut out extraneous information. For example, rather than
beginning the email with “This is a courtesy notice to let you know that at least one vehicle associated
with your email address has accrued nearly $350 in unpaid parking or camera summons judgement debt,”
the redesign cut the jargon and simply stated “A vehicle associated with this email has unpaid parking
fines.”
Drivers need to act promptly to ensure their vehicles do not get booted or towed. Procrastinating for just
a few weeks can mean hundreds of dollars of additional costs in booting, towing, and execution fees. To
reduce procrastination around addressing these fines, we included a bolded deadline in the body of the
email, by which drivers needed to act. Directly following this deadline, we included three succinct bullets
explaining how drivers could address their tickets, so drivers could easily understand all their options.
Personalization may increase the perceived authenticity and relevance of automated messages. Indeed,
our pre-pilot MTurk test suggested personalization might be eective at increasing the likelihood a driver
attempts to address their tickets. When compared to the email the DOF previously sent drivers, a higher
percentage of MTurk users attempted to address their ticket (by clicking a link in the email) when they
reviewed our behaviorally redesigned email, which included personalized elements like the driver’s plate
number.
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To explore whether additional personalized elements would ultimately increase the number of
drivers who act promptly in the real world, we created one version of the design that featured the driver’s
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The email included other behavioral elements described in this brief, like simplified language and deadlines, so we are not able to isolate the
impact of personalization alone in our MTurk testing.