The Road Development Authority (RDA; Sinhalese: මාර්ග සංවර්ධන අධිකාරිය; Tamil: வீதி அபிவிருத்தி அதிகார சபை) is the premier highway authority in Sri Lanka and is responsible for the maintenance and development of the National Highway Network, comprising the trunk (A class) and main roads and the planning, design and construction of new highways, bridges and expressways to augment the existing network in the country.