The 'Fleet Averaging Rule' takes effect in California 1/2009. It does not require anyone to switch to an electric truck. It requires owners of medium (4-25 forklifts) and large (25+ forklifts) fleets to maintain an average emissions (NOX&HC) level, based on the emissions rating of each LSI engine (electric trucks have an emissions rating of 0, for this purpose).

Small fleets (1-3) are exempt. There are other exemptions and restrictions, as well. If you are in CA and you have at least 2 more forklifts, you will need to do something to reduce your fleet average, as the two older IC trucks are uncontrolled and will bring the average way up. There are retrofits for some older engines.

CARB (California Air Resource Board) has a calculator on its site to figure out your fleet average.