More widely used in Europe than in America, retractable concrete-reinforced pillars, placed underneath the road, do a much better job than wooden toll arms or even tire-snagging spikes at stopping traffic from getting into restricted areas.
As this video demonstrates however, some of the (evidently) less intelligent drivers on the road have tried to outsmart these simple pilings and have failed miserably, to the detriment of their vehicles.
Bit of advice: if you see one of these columns retract to let a car through, don't try to squeeze through. It won't work. But watching others try is a load of fun! (The music is just the icing on the cake.)
[Source: Motorpasion via Winding Road]