I don't know that hybrid technology is ready for long haul trucks.

One of the uses of hybrids has been in buses. The city of Elk Grove has serveral hybrid buses that work great on local routes in town. But they couldn't maintain enough electric power on the freeway to even keep the AC running when they used them for routes into Sacramento. Lot of fuming passengers when it was 110 in July.

Trucks don't need that much power to move heavy loads on level highways, but I think they will slow to a crawl on grades with the smaller engines needed to get the gains of hybriding. Going over the Sierras or passes like the Grapevine in southern CA would require a lot of electric boost, that woudl require a lot of battery. It just starts getting really expensive. But like buses, local delivery trucks (the bobtails that bring your paper clips for OfficeMax and others) would be great platforms for diesel hybrids.