snapping turtles are rather prehistoric looking:

http://www.cortland.edu/herp/keys/im...s/cserpelg.jpg

http://pelotes.jea.com/AnimalFact/Reptile/snapturt.jpg

but the babies are pretty cute:
http://www.boingboing.net/BabySnappers.jpg

Snappers on the road will try to spin around to face you when you threaten them. They can turn pretty fast, but not that fast. They do have long necks, can reach out and bite very quickly, and can reach your hand if it's maybe halfway between their front and their tail, but they cannot reach all the way around to bite your hand if you're holding them by the tail. It's not really that hard to be quick about getting behind them and grabbing the base of their tail. just keep your hand well away from the front half of them. Then you can drag them off the road if they are really heavy. Smaller ones can be carried by the base of their tails.