You can only select one commodity class to indicate the type of property transported by all the vehicles in a particular fleet. (See below)

All Commodities - All kinds of commodities/goods (used with fleet types PVT, COM, CON or FHL).

Logs - Hauls logs (used with fleet types PVT or FHE).

Exempt - Hauls interstate exempt commodities (used with fleet types FHE and FHR).

Household Goods - Household good movers (used with fleet type COM).

Passenger Bus - Buses carrying passengers (used with fleet type COM).