Network (LHIN) Hospital Partnerships. Boomerang Health, in Vaughan, is a centre that provides multidisciplinary rehabilitation and medical services geared specifically for children and adolescents, in collaboration with The Hospital for Sick Children. Transportation The arterial road network in York Region is a grid, with most roads running north–south or east–west. This was done under the orders of British surveyor Augustus Jones during the 1790s. York Region assigned approximately 50 roads as York Regional Routes, meaning that the cost of maintaining of these roads is paid for by York Region. The major highways in the Region are: Highway 7 (east-west) Highway 9 (east-west) Highway 48 (north-south) Highway 400 (north-south) Highway 404 (north-south) Highway 407 (east-west) Highway 427 (north-south) Former highways include: Highway 11 (north-south) Highway 27 (north-south) Highway 47 (east-west) Highway 49 (east-west) Highway 50 (north-south) Note: Highway 27 and Highway 50 are still referred to as such on municipal road signs, but are no longer provincial highways. Air transportation Most air travel is served by Toronto Pearson International Airport, which is outside of York Region and is Canada's largest airport. Buttonville Municipal Airport is a regional airport in Markham, used for general aviation and business aircraft. Markham Airport is a private aerodrome in Markham. There are also a few unpaved airports serving the region: Hare Field in Holland Landing (East Gwillimbury), Belhaven Airport in Georgina, and Stouffville Aerodrome north of Stouffville. Public transportation York Region is served by: York Region Transit (YRT), which includes the Viva bus rapid transit network GO Transit, which offers bus and train service Toronto Transit Commission (TTC), which has several bus routes which cross York's southern border, and which provide service along many north–south arterial streets in Vaughan, Richmond Hill and Markham. Since December 17, 2017, Central Vaughan has been served by the University portion of the Line 1 Yonge-University of Toronto's subway system, and a future extension of the Yonge Street portion of the line will eventually serve eastern Vaughan, Richmond Hill, and Markham. Until 2001, the towns of York Region operated separate public transit services, which did not connect very well with each other. YRT was created by the Regional Government to combine five of these services: Vaughan Transit Markham Transit Richmond Hill Transit Aurora Transit - merged in 1999 with Newmarket Transit Newmarket Transit Since 2001, bus routes have been extensively enhanced in the five communities which had pre-existing services, but YRT's