I found some offroad lights for my truck but the company that has them says that they are european 12vdc. what is the difference between european and US 12volt vehicles?

 

Possibly polarity... some Euro's used to have positive ground but I don't think that is the case anymore.

In any case, unless there is something in the lights besides light bulbs (diodes, transistors, etc), it won't make any difference.

 

Electricity in Europe works the same as the electricity in the states. If the lights come with instructions you will not have any problems.