The Peltzman Effect says that if gubmnt officials impose restrictions, trying to make some activity safer, people will take more risks with it. The end result could easily end up with more injuries and greater social costs. I wrote about this effect earlier here and here.
Usually tests of the hypothesis have been one way, e.g. what happens to pedestrian deaths and injuries when drivers are required to wear seatbelts? [answer: they increase because drivers tend to take a bit less care in their driving.] But now many local councils in Scotland are planning to conduct a reverse test of the hypothesis [h/t to Brian Ferguson]:
WHITE dividing lines will be removed from roads in dozens of Scottish towns and villages, under plans to improve pedestrian safety.
Lines separating lanes of traffic have been a feature of the nation's roads for generations. But now experts believe they could be making drivers feel too safe, encouraging them to drive too fast and putting pedestrians at risk. ...
A key recommendation is the removal of centre lines to reduce the speed of traffic in towns and villages in the area.
Mr Gabriel states: "Although white centre lines can greatly assist drivers on major unlit rural roads, research in Wiltshire has shown that when white centre lines on lit roads within a 30mph speed limit were not replaced, traffic speeds and accidents were both reduced. It is, therefore, proposed that a similar experimental policy should be adopted in Aberdeenshire when roads with street lighting within 30mph speed limits are resurfaced or surface dressed.
"Short sections of line would still be reinstated for guidance at traffic islands or junctions.
Neil Greig, a spokesman for the Institute of Advanced Motorists Motoring Trust in Scotland said: "The concept is quite simple - that if you come round a corner and you are not sure exactly what the priorities are and where you should be on the road, then you will cut your speed."
But he stressed: "A number of factors will have to be taken into account. Novice drivers and older drivers, for example, quite like to know where they're supposed to be on the road and like to have a white line to tell them where to go.
"You don't know how they are going to react in these sorts of situation and, if you get too much uncertainty, you might get a lot of dithering and that could lead to road rage and all sorts of things. ..."
A spokeswoman for the Royal Society for the Prevention of Accidents also welcomed the proposals.
She said: "Schemes similar to this have been shown to have made a positive difference."
Calculating the net social benefits of removing the white lines will involve collecting a lot of data. How many more auto accidents will there be, if any, and at what cost? How many fewer pedestrians will be injured or killed, if any, and at what savings? I am not persuaded
ex ante that there will be a cost savings or a net benefit to the removal of the white lines, but I applaud the experiment. And I hope the councils carrying it out will make detailed data available to various researchers.
To be really hard-nosed about it, what if the pedestrians saved are a bunch of dottering old fogies like me who have comparatively short expected remaining lifetimes and even shorter expected times during which they will be contributing to GDP; and at the same time, what if the white lines actually save more younger people with longer expected lifetimes and longer expected periods of contributing to GDP? Should these differences play a role in our cost-benefit analysis?
Addendum: When we were discussing this article, Brian reminded me of another option that might also have net social benefits: put spears (not airbags) on the steering wheels, pointed at the chests of the drivers, and don't allow drivers to wear seatbelts. Even if this policy did not have net social benefits, it would certainly induce most drivers to take more care.