All three vehicles used a through-the-road hybrid configuration. That means that the internal combustion engine drove the front wheels through a conventional automatic (MTU, OSU) or manual transmission (UWM) while an electric motor drove the rear wheels. The only mechanical connection between the ICE and electric drives is through the tires and road.
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The MTU and OSU vehicles also had a belt-alternator starter system similar to the GM mild-hybrid system on the production Saturn Vue and Aura. The Michigan Tech vehicle started off in electric mode pulling away from a stop silently before the engine fired up once we were in motion. The engine started up smoother than some of the production hybrids I've driven recently. The team from northern Michigan finished 11th overall and lagged behind in areas like handling, emissions and fuel economy.
The Ohio State team finished fourth overall and their diesel-powered machine and scored well in the handling, acceleration and on-road emissions tests. Like the MTU vehicle it also had smooth engine restarts and had better low speed acceleration thanks to the torque of the diesel engine.
The University of Wisconsin team didn't use a start-stop system but apparently made up for it with their manual transmission. The UWM Equinox had basically the same drivetrain as the winning vehicle including the engine, transmission, motor and battery. The cheeseheads finished second overall and performed consistently in most tests.
You can listen to the teams describe their cars right here