They didnt have to do this on a public highway. A large parking lot would have be sufficient. Why should other motorists be subject to harm because a couple hackers and a reporter want to make a story. They could've easily gone on one of the 24hr news channels to scare the masses.
Or heck even a quiet public road. There are tons of inter-state roads that have single-digit numbers of cars an hour. Just drive out into the desert and play around.
PS - Plus due to the flatness of these roads, with large de-facto shoulders you can pull off onto, they're much safer even ignoring traffic levels.
