Drivers in China are angry all the time too! But it's not cyclists they fantasise about smashing into ditches, it's other drivers driving behind them at night with their headlights on full beam that's the #1 road rage trigger out there. Hence the invention of some horror decals that are only visible when the driver behind has got his or her headlights turned to max.
The idea is a bit flawed, as it relies on people believing ghosts are real. Numerous decals are on sale featuring spectres and horrific images of torture -- mostly nicked from films -- which might, if the following driver believes in ghosts or is extremely suggestible, spook the person sitting behind.
Another flaw is that you might turn your headlights to full beam to specifically see the sticker thing someone's stuck in their car, making the problem worse. God, it's all so complicated nowadays isn't it? [Mashable]