We build a spatial computable general equilibrium model to assess the spatial economic impacts of the completion of ring road sections on the highway network system in the Greater Tokyo Area. Although every prefecture obtains positive benefits in terms of the prefectural sum, some municipalities experience negative benefits. The outputs of the service sector are less tradable than those of the primary and manufacturing sectors, and they increase for a broader area. The regions with net production increases in all sectors gain positive benefits. Meanwhile, several municipalities whose production decreases in all sectors experience welfare improvements.