In the commercial vehicle world, fleet managers will determine the growth rate of hybrid vehicles, according to ABI Research. These fleet managers face a tough business question: will the total cost of ownership of a vehicle equipped with hybrid technology be less than that of an equivalent conventional vehicle? There is a steadily growing list of hybrid systems available for commercial vehicles. The cost of these vehicles is expected to come down as the technology matures and the volumes grow, but that will not happen until purchasing managers have greater confidence in the operational characteristics. Fuel savings and reduced emissions are being measured, and maintenance logs show lower costs, especially for brakes. Yet, ABI Research cautions that the results are very specific to duty cycle, and there have been instances where hybrid drive technology has proved to be less appropriate than conventional diesel engine power.