The folks at General Motors this week continued with hot weather testing of the Chevrolet Volt. The Volt went through a series of Grade Load tests on the Circle Track with a towing dynamometer, which simulates endless hill and mountain climbing. The towing dyno can simulate climbing an incline with anywhere from a 2 to 10 percent grade when it is attached to the Volt, and today's tests were of the 5 and 7.2 percent variety.

A towing option will not be available for the Volt, nor is it recommended--in fact, the team at the GM Desert Proving Grounds in Yuma, Ariz., cut the rear fascia to attach the hitch. This test put a lot of stress and strain on the vehicle to determine how durable it will be climbing a mountain in the hottest of conditions. It was about 103 degrees on Monday when the test was conducted.

Lead durability-testing engineer Steve Pratt described how the mountain-grade test measures the vehicle's performance while driving up mountains in the following video.

(Photo Courtesy of General Motors)