I think you’ve got the wrong terminology. I wonder - do you really mean CB, or are you just calling a vehicle mounted radio a CB?
If you want a radio system - then it can happily be a mix of hand-held and vehicle mount radios. Clearly - a fork lift would be safer to drive with a fixed radio, but you need to decide practical things. Do you need to call Fork Lift 2, or do you need to call Joe, who may, or may not be driving the thing? Personal radios are great, but you also then need to keep details of who is where. Efficient radio systems need planning. Are they for checking people need a tea break, or do they also fulfil a proper safety function?
In most places in the world - there are licence free and licensed business radios available - and now there are even IP based systems that work via cellular or wi-fi. For business, do you want to reply on a system where the local kids can annoy your workers, or where at some times of the year, you can’t hear the warehouse, but can hear people in foreign countries? Are antennas a problem. CB has big ones, business radio has smaller ones? Do you want extra features - when the guy presses his transmit button, all the radios light up and in the display it says FORK LIFT 1 - These features mean more expensive radios of course?
What do you really want the things to do? Work that out and you can select the most appropriate system.