York's location on the River Ouse, and in the centre of the Vale of York, means that it has always had a significant position in the nation's transport system. The city grew up as a river port at the confluence of the Ouse and the Foss. The Ouse was originally a tidal river, accessible to seagoing ships of the time. Today, both of these rivers remain navigable, although the Foss is only navigable for a short distance above the confluence. A lock at Naburn on the Ouse to the south of York means that the river in York is no longer tidal. Until the end of the 20th century, the Ouse was used by barges to carry freight between York and the port of Hull. The last significant such traffic was the supply of newsprint to the local newspaper's Foss-side print works, which continued until 1997. Today, navigation is almost exclusively leisure-oriented. Roads Like most cities founded by the Romans, York is well served by long-distance trunk roads. The city lies at the intersection of the A19 road from Doncaster to Tyneside, the A59 road from Liverpool to York, the A64 road from Leeds to Scarborough and the A1079 road from York to Hull. The A64 road provides the principal link to the motorway network, linking York to both the A1(M) and the M1 motorways at a distance of about from the city. The trans-Pennine M62 motorway is less than away providing links to Manchester and Liverpool. The city is surrounded on all sides by an outer ring road, at a distance of some from the centre of the city, which allows through traffic to by-pass the city. The street plan of the historic core of the city dates from medieval times and is not suitable for modern traffic. As a consequence, many of the routes inside the city walls are designated as car-free during business hours or restrict traffic entirely. To alleviate this situation, six bus-based park and ride sites operate in York. The sites are located towards the edge of the urban area, with easy access from the ring road and allow out of town visitors to complete their journey into the city centre by bus. Public transport within the city is largely bus-based. First York operates the majority of the city's local bus services, as well as the York Park & Ride services. York was the location