Construction of the second phase of the OCH from Kaduwela to Kadawatha began in 2012. The 4-lane expressway of total length 14.36 kilometers cost Rs. 44.88 billion rupees.
The cost included construction of five overpass bridges and the 250 meters long 6-lane bridge over the Kelani River. The 4-lane expressway is to have 3 toll office buildings and 6 toll plazas.
The OCH runs around 20 km away from the city center of Colombo, connecting radial routes and has a total length of 29.2 kilometers. The construction of the 29.2km Outer Circular Highway was carried out in three phases.
It is to be developed as a 4-lane Highway with provision for future expansion to six lanes. The design speed of the Highway is 100 km/h.
The northern end of the highway is located at Kerawalapitiya on Colombo-Katunayake Expressway and the southern end is located at Kottawa on Colombo-Ratnapura-Wellawaya-Batticaloa road where Southern Expressway meets OCH.
The 11-kilometer first segment of the OCH from Kottawa to Kaduwela was opened for public use last year.
The final phase of the project will complete the 9.3 kilometer section from Kadawata to Kerawalapitiya connecting the Colombo-Katunayake Expressway to the Southern Expressway via the OCH. Thereafter it would become one expressway from Katunayake to Matara passing the Gampaha, Colombo, Kalutara and Galle Districts.
The OCH is expected to provide an effective bypass for North-South bound traffic and to minimize traffic congestion and encourage development away from the highly populated urban areas in the Western province achieving better balance for growth.