The Vehicle Arrestor by Barrier1 Systems is a vehicle-stopping road barrier that can pop up out of the ground in a mere 2 seconds. How serious is it? Well, it can take a 15,000 pound truck and turn it into little pieces of junk without a lot of effort.
As you can see in the below video, this thing isn't messing around. It's meant for places where security is necessary, like the entrance to government compounds and such. But that doesn't mean you can't install one at the end of your driveway to keep undesirables away, does it?