www.facebook.com The HUMMER HX concept may ride similar to its predecessors but there are big differences -- including its size and fuel source. The vehicle, which made its debut at the 2008 North American International Auto Show (NAIAS) in Detroit, is smaller than the brand's current models, measuring 171 inches long, 81 inches wide and 72 inches tall. The HUMMER HX concept also downsized its fuel-consumption, running on a 3.6L V6 engine that can burn E85. General Motors reports three designers, fresh out of school, sketched the vehicle before it was put into production. The vehicle also features a built-in, forward-facing camera that drivers can use to record their off-road excursions, and then replay on the monitor located inside the SUV. While the HUMMER HX concept does not include a radio, it does contain speakers that enable drivers to plug in their MP3 players or other similar devices.