While I was biking along a side road near Silver Plume, CO I noticed that the same several cars kept going back and forth along the street. After the fourth or fifth time one of them passed me I asked what they were doing. Apparently they had driven all the way from Detroit, MI where they worked for GM. The whole point of the trip was to test the cars at higher elevation (9000+ ft) to see if the onboard computers were able to correctly deal with the change in altitude, especially for burn rates, etc, given the decrease in available oxygen.
The driver also told me that Jaguar rented several large outdoor refrigerated boxes nearby, so they could do cold-start tests. Basically they leave the cars in the box until they freeze, and then start them up and retest everything about the car. This makes sure that the car will function normally in cold weather, without having to actually wait for cold weather to do the testing.