 Although Rocar De Simon U412 was a fairly modern vehicle with EURO 2 engine and automatic transmission, and chopper in case of some trolleybuses it did not prove a very big success, as many other transport companies still preferred second hand buses/trolleybuses or other new buses/trolleybuses (MAN, Mercedes, MAZ, Ikarus, BMC), accentuating the deteriorating situation of ROCAR.Rocar De Simon (E/U 412) remained in production until the factory went bankrupt.As a last attempt in their struggle, ROCAR was courted by SOLARIS BUS, for a partnership to assemble URBINO busses from Poland as CKD, but eventually cooperation between ROCAR and SOLARIS BUS failed, only one vehicle is supposed to be built (other said that only the badge ROCAR was attached to it, the bus was in fact made in Poland).