How do I spawn trucks (Gavril T-series) in traffic?

Title. I want gavril t series to spawn in traffic, but the biggest truck i got in traffic is the MD series. I tried using the start traffic button, but it doesnt dispawn the car after im far enough from it. Any way to "modify" traffic vehicles im looking for?

 

You cant spawn trailer trucks with only the AI button unfortunately. You need to spawn a tractor unit, then attach a trailer to it, then press 'Start AI Traffic'. That should work

 

You could also try the Vehicle Groups Manager.

 

I tried but couldnt figure out how to save a group