"Making driving more dangerous forces drivers to focus harder, and focusing harder makes drivers less likely to screw up."
The inescapable conclusion is that we should get rid of seat belts, mount the driver in a plexiglass bubble in front of the front bumper, and put a bloody great spike in the middle of the steering wheel.
In a related question, there is some evidence that bike helmets may lead to greater risk taking and thus increase the likelihood of a crash (though bike helmets pretty definitively reduce the risk of head injury should a rider be in a crash).
Your "inescapable conclusion" would probably depend on whether the driver actually perceived the increase in risk. The spike and bubble might, but removing airbags might not.
That is a pretty far off base conclusion, the goal is to make roads feel unsafe for drivers so they go slower, and reduce or eliminate commute distance, that is how roads are made safer.
For example, a common strategy is to narrow a road from 4 lanes to 2 with a center median, being either a turn lane, planter with half height jersey barrier (directs cars wheels back onto the roadway), or barrels filled with water (which absorbs impacts and makes roads much safer). Tactics like these make roads feel more claustrophobic and thus "dangerous", but the road is ultimately much safer in the event of an accident, and accidents are less likely due to drivers being more alert because of the narrow roadway.
TL;DR: Wide roads lull you into a false sense of safety, narrow them!
I had an other smart acquaintance who believed replacing airbags with spikes would make people safer.
Ridiculous.
That's like saying that decreasing did production will make people use food smarter and starve less. It'll improve the efficiency of food usage, but fewer people won't starve.
Steering wheel spikes will improve driver habits, but people won't be safer overall.
The inescapable conclusion is that we should get rid of seat belts, mount the driver in a plexiglass bubble in front of the front bumper, and put a bloody great spike in the middle of the steering wheel.
Any takers?