increases – it does obviously, but not as much as you might think.
About a third of drivers report speeding because of time pressure,
like being late for an appointment.^7 However, we tend to over-
estimate how much time we will save by driving faster. On a trip
I took from Macon, Georgia, to Atlanta, my GPS display predicted
that the drive would take 90 minutes. I figured that if I drove just
a bit faster than the 65 miles per hour speed limit, I would get to
Atlanta sooner. As I pressed the accelerator down, my speed crept
up to 70, at times maybe 75. Okay, 80. Strangely, the GPS display
didn’t refresh and show a new estimated time. I thought maybe the
GPS hadn’t calculated my new speed yet, and that maybe it just took
a while to refresh. Nope. I arrived in Atlanta about 90 minutes after
I left Macon. What gives? The estimated time of arrival actually
doesn’t change that much, despite the fact that you are driving
faster. This miscalculation is called “the time-saving bias.”^8
Let’s break it down. Let’s say you live 10 miles from work
and you take a local road to get there. If the speed limit on that road
is 20 miles per hour, it will take you about 30 minutes to get to
work. If you increase your speed to 30 miles per hour, you can get
there in only 20 minutes, a whopping 10 minutes faster. But if your
job is 10 miles down a highway where the speed limit is 50, you
have a different situation. The same 10 miles per hour increase
actually results in less time saved if your initial speed is higher.
Zooming 60 miles per hour gets you there only two minutes faster.
It’s not exactly worth getting a speeding ticket to shave two min-
utes off your journey.
High sensation-seeking individuals tend to be particularly
susceptible to this time-saving bias. This bias, together with their
thrill-seeking and boredom susceptibility, leads high sensation-
seekers generally to choose higher speeds than their low and aver-
age sensation-seeker counterparts.^9 Some research suggests that
fast driving can produce thrill in those who score high in thrill-
and adventure-seeking but also can be an illusion of control that
results in feelings of superiority for some drivers. Ask around, some
people are really proud of their driving prowess, no matter how
dented their cars might be.
I learned in Drivers’ Ed in high school that two car lengths
from the car in front of you was a safe following distance. You
needed to keep at least that distance because you never knew
what could emerge ahead. The car you’re following could stop
suddenly, its driver could toss things out the window, a rabbit142 / Buzz!Downloaded from https://www.cambridge.org/core. Access paid by the UCSF Library, on 11 Nov 2019 at 14:20:10, subject to the Cambridge