If you ever see that show, I think we had seen it on a Discovery or The History Channel, it's really interesting. They can only drive so fast, I think less then 20mph, over the lakes or they create a wave under the ice that will blow out the ice when they near the shore.
We are friends with a couple that are truck drivers, they said they know people that do this run and they drive with their door ajar (in -40 degree weather, mind you), just in case their trucks bust through the ice they can bail quickly!!
now that is something!
This is a quote from one article on it: "If you're still wondering just how strong the ice is, in 1978 RTL transported a 190,000-lb generator over the ice road from Yellowknife to Port Radium on Great Bear Lake, over 300 miles away. Feel better?"