I’m naturally skeptical of any promotional videos from an auto manufacturer. I’m grumpy that way. But I admit to being won over by this entry from Volkswagen’s campaign “The Fun Theory,” which is “dedicated to the thought that something as simple as fun is the easiest way to change people’s behavior for the better.”

As part of the campaign, Volkswagen awarded 2,500 euros (about $3,345) to someone who came up with an idea that could do just that.

The winner was Kevin Richardson’s “Speed Camera Lottery,” which proposed that people who were caught on camera driving within the speed limit would be entered into a lottery to receive cash prizes — with the winnings being drawn from the fines of drivers caught speeding.

The idea so appealed to the powers-that-be in Stockholm, Sweden, that they gave it a whirl. And it worked. Average speeds went from 32 kmh to 25 kmh (20 to 15 mph) during the three-day experiment, a reduction of 22 percent.

Of course, Sweden is a nation so sensible about the impact of automobile traffic on people that they actually have their sights set on a goal of zero traffic-related fatalities and serious injuries. The strategy for getting there is called Vision Zero, and it was adopted by the Swedish Parliament in 1997.

In the case of the U.S., concerns about privacy and fines have long obstructed widespread implementation of speed cameras. Throw in some filthy lucre, though, and maybe you could get people to play along. Sounds like fun, right?

Hat tip to Planetizen and Streetsblog LA.