Premise: The Parma trolleybus system (Italian: "Rete filoviaria di Parma" ) forms part of the public transport network of the city and "comune" of Parma, in the region of Emilia-Romagna, northern Italy. In operation since 1953, the system presently comprises four urban routes.
Hypothesis: Since 1953 the Parma Troleybus system has been comprised of four urban routes.