Were the roads of the 1930s littered with fallen pedestrians, lying prostrate after auto collisions, fainting bouts or rapid-onset naptimes? One might think so to judge from this hoary concept for a "roller safety device," which the divine site Modern Mechanix notes will "literally sweep a fallen pedestrian before it and thus save him from being crushed to almost certain death beneath the heavy wheels."
The highly suspect invention, appearing in the March 1931 edition of suspect-invention treasure trove Modern Mechanics, is meant to alleviate that most tiresome chore of Great Depression motoring: the removal of tangled-up plebes from your factory-polished axles and gears. Well, the way it's phrased in the article makes it seem like it's a pedestrian-safety feature. But a rational consideration of this device would indicate it'd have the same effect on a human body as a cannonball would on a wedding cake.
A quick primer on the safety device: It consists of a "grooved roller" fixed to an extension beam that's connected somehow to the gearbox. During an average work day, a driver riding a truck through town leaves the safety device in a raised position, so that it acts like a bumper on other vehicles. When the operator spots the tell-tale snow-angel shape of a collapsed pedestrian, however, he engages a switch that drops the roller to the pavement. The result is that the vehicle gently nudges the stricken walker along the road, like a dead log, while the trucker brakes to a safe halt.
Of course, given the mass and velocity of a truck, what would probably happen is that the pedestrian would be spread over the pavement like cherry jam on toast. Or the trucker wouldn't deploy the safety device quick enough and would barrel right over the fallen person, with the same lethal outcome.
Believe it or not, this wasn't the only pedestrian cow-catcher that traffic-safety pioneers were tinkering with in the early twentieth century. I also found this "rescue device" from Paris circa 1924; according to the Nationaal Archief in The Hague, the "kind of shovel on a car" was meant for "reducing the number of casualties among pedestrians." You're forgiven if all it reminds you of is this.