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”