Yesterday lunchtime on
Radio 2 a couple of men (I didn’t catch their names) were debating whether
families are safer in their vehicle if that vehicle is displaying a Baby On Board sign. It was a heated
debate with one man asserting that displaying a Baby On Board sign does make those families safer because other
drivers are likely to drive more carefully around vehicles with babies in them;
and the other man arguing that this is probably wrong because, and I quote “It’s not as though you deliberately try to
crash into a car that doesn’t have a Baby On Board sign displayed, do you?”.
Alas, both contributors
missed a whole host of economic factors that would have informed their
contributions better. For example, from what I recall, economist Sam Peltzman
conducted a long study into driver behaviour. One conclusion he reached
was that drivers with a Baby On Board
sign tend to be involved in fewer accidents than ordinary cars. But that
doesn’t tell us as much as we think about whether cars with Baby On Board signs are safer. This is
where our first radio contributor went wrong: simply concluding that fewer
accidents means safer driving is a model of over-simplicity that just won’t do.
Let’s assume it is safer
to be in a Baby On Board car – by how
much is it safer? That’s an incredibly difficult question. That Baby On Board cars have been involved in
fewer accidents isn’t 100% conclusive, because car drivers cause accidents
between two other cars all the time, and drive off unawares (or unwilling to
stop). But it’s even more complex than that. It could well be the case that
the sort of person who would buy a Baby
On Board sign for their car is the sort of person who is already risk-averse
and mindful of careless driving – so the odds of those kinds of people being
reckless or careless may well have been slimmer anyway.
Then there is the group of
drivers who are reckless by heart, but who have children and then buy a Baby On Board sign. What
percentage of those drivers become less careless after the Baby On Board sign and what percentage become more careless? Nobody really knows – and these are important statistics for our overall
conclusion. Quite naturally I can conceive of many new mothers being
extra cautious and less careless than when they only had themselves to think
about.
But doubtless there will
be some who become even more carefree in the presence of a Baby On Board sign because they believe that their sign is inducing
more careful driving and increased braking distance from other drivers around
them who’ve seen the sign. We know this is likely to be true because we
know already that there are many cases in which perceived safety increases
reckless behaviour (seatbelts and contraceptives being two examples).
The upshot is, a proper
analysis has to factor in not only that there are likely to be results that
confound our expectations, but also that the complexities of human behaviour
mean that sometimes results that are consistent with our expectations could be
this way for reasons that weren’t properly understood or even considered at
all.
* As well as having the
consideration of safer driving, Baby On Board signs are also, of course, there
to alert emergency services that when they arrive at the scene of an accident
there could be a child on board. However, the success of this is contingent on
parent drivers actually taking the sign out when they are not travelling with
children, otherwise emergency services staff can waste valuable minutes looking
for a child that isn’t there. A quick Google
search indicates that this fact is shockingly absent in many parent
drivers’ repertoire of information:
“Only 1 % of parents with Baby On Board signs removed
it when they were driving without a child in the back 99% said they didn’t
think it mattered, or weren't aware of the real use of the Baby On Board sign”
