 ACHD covers the entirety of Ada County, including the six cities within it, and it is responsible for short-range planning, construction, maintenance and improvements to Ada County's local roads and bridges (excluding state highways like Eagle Road, Interstate 84, the Connector and overpasses, which are operated by the Idaho Transportation Department).The district maintains and operates approximately of roads and streets in Ada County, with an estimated value of $3 billion.This infrastructure includes facilities that range from multi-lane, arterial streets with a computerized signal system, to narrow, farm-to-market roadways.