Signs in Heilbronn, pt. 2

Signs in Heilbron, pt 2
Originally uploaded by allanimal.

Here is the second installment of interesting signs in Heilbronn. Germany is using supposedly "international" and "language-independant" signs, so it is inherently obvious what the sign means.

I am still trying to figure out this one.

Cars falling into Lava?
Beware of Sinkholes?

I dunno, and didn't much care since I was on my bike at the time - obviously, being on a bike and the picture shows a car, it doesn"t apply to me!