Car tires (P) work great on a single axle trailer and light weight tandem axle trailers. WE can use P/LT or ST on trailers but cannot use a ST on a tow vhicle.
Most utility trailers come OEM with P tires. In fact before the tire mfg gave us the ST tire all we had for our RVs were passenger and truck tires for our heavier trailers.
I've ran P tires on all my single axle boat trailers (3500 lbs) and even a few tandem axle trailers with 2000-2750 lb axles. There not speed restricted as a ST and will last longer.
Remember the P tire's load capacity when used on a trailer shall be reduced by dividing by 1.10