I was curios about it too. Straight googling was fruitless but guessing at the solution (Something within the common functionality of a truck and which would be

I was curios about it too. Straight googling was fruitless but guessing at the solution (Something within the common functionality of a truck and which would be "obvious" in hindsight and thus work for a riddle.) The google string that worked brought this up: http://rawksoup.com/neighborhood/pg/blog/read/1987/brain-teaser-stuck-truck http://rawksoup.com/neighborhood/pg/blog/read/1987/brain-tea...