I'm surprised heavy Class 8 trucks like that would go all-electric.
Always expected more of something like http://www.rigzone.com/news/oil_gas/a/1 ... avy_Trucks
becoming the norm, or maybe the Honda Accord's series+parallel hybrid arrangement which eliminates complicated and heavy gearboxes.
(The Accord hybrid's arrangement is cleverly simple, acting as a series hybrid for low speeds, and a parallel hybrid for high speeds, with only one clutch, ........ and an over the road trucker could reap the benefits of a diesel operating efficiently at high cruising speeds, while allowing the series hybrid electric motors to work at low speeds (traffic, in-town, etc.), just like the Accord's.) Optimizes the high-speed and low-speed regimes outlined in http://articles.sae.org/11853/
Car and Driver's Accord hybrid diagram (note one automatic synchro-clutch makes it a parallel if engaged):