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Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects Chapter 20 Road Extension and Widening Projects 20.1 Introduction Colombo has many roads that have insufficient capacity to deal with current traffic demand. There are also missing links that if constructed would help to alleviate traffic congestion by creating a more efficient road network. The objective of this chapter will prepare designs for the Pre-FS projects that will either increase capacity via road widening or will produce a more rational network by constructing missing road links. In undertaking this, social impacts were taken into account and a balance had to be found between reducing congestion and mitigating social impacts. Therefore, the designs for some of these projects were lowered to minimize adverse impacts. Finally, where design work has been completed or is in progress by a local organization, the results of this work were confirmed and utilized for the design work of this study. Cost estimates were also prepared. 20.2 Outline of Projects Table 20.1 outlines the project to construct two missing links (the Marine Drive extension) and Table 20.2 outlines the locations of the five road widening projects. Figure 20.1 provides a map of the projects. RDA or the Western Province Road Development Authority (WPRDA) has completed or is in process of completing detailed design for some of these roads. Additional information regarding the timelines and tasks can be found in Appendix 20. Table 20.1 Marine Drive Extension Road Road Length Existing Proposed Detail No Road Name ID Class (km) Width (m) Width (m) Design North A 2.0 - 18.3 Completed1) 1 R7 Marine Drive South A 1.7 - 18.3 DNE2) 1) Detailed design has been completed by RDA. 2) DNE: Does not exist Source: This Study Table 20.2 Road Widening Projects Road Road Length Existing Proposed Detail No Road Name ID Class (km) Width (m) Width (m) Design B152 B 5.2 Completed B425 B 5.9 DNE 2 R14 6.0 15.2 Eppamulla-Pamunugama B 2.8 DNE Road Nugegoda-Katiya Junction- Completed1) 3 R20 B 2.1 6.0 15.2 Pepiliyana Road (1.3km) Thalawathugoda- 4 R21 B 3.2 9.0 21.8 Completed Pannipitiya Road Thalawathugoda- 5 RWP2 C 4.2 5.0 11.9 DNE2) Koskadwila Road Pannipitiya-Tumbowil 6 RWP4 D 7.2 5.0 10.9 DNE2) Road 1) Detailed design work for only 1.3 km of R20 is completed, and remaining 0.8 km is not existed. 2) No designs for RWP2 and RWP4, which come under the jurisdiction of the WPRDA, are available. Source: This Study 20-1 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects Figure 20.1 Locations of Road Extension/Widening Pre-FS Projects 20-2 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects 20.3 Project Design The following basic concepts are applied in the design work of the study: • Completed or on-going design work by local organizations is inspected and revised as necessary for the designs of this Study; • For sections without any design work, the existing road alignment is basically followed with regards to future improvements; and • The design vertical profile is considered to be at the same level as the existing road. (1) R7: Marine Drive Extension Design Overview Marine Drive functions as a bypass for Galle Road and runs along the railway near the coast. The existing part of this road extends from Bambalapitiya Station Road to Ramakirishna Road and should be extended north to Kollupitiya and south to Dehiwala in order to attract a greater number of long-distance trips to increase its effectiveness as a bypass (Figure 20.2). RDA has completed the detailed design work for the north section and has made arrangements to acquire the necessary land for the right-of-way. Note that the cross section contained in the detailed design work for the north part has been examined and it is recommended that it be utilized for the south section as well, which would unify the specifications for this road. The alignment of south part is set along the railway so as to minimize land acquisition and social impacts. Figure 20.2 Layout of Marine Drive Extension Cross Section The proposed right-of-way will have a four-lane carriageway with a center median and footpath on either side of the road. Drainage will be located under the foot path. The typical cross section for Marine Drive is shown in Figure 20.3 and will be used throughout the entire length of the extension. Further details on the design aspects of Marine Drive are shown in Appendix 30. 20-3 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects 18.30 3.40 3.40 1.20 3.40 3.40 1.75 1.75 Foot Path Carriageway Median Carriageway Foot Path Figure 20.3 Proposed Typical Cross Section for Marine Drive (2) R14: B152/B425/Eppamulla - Pamunugama Road Design Overview Project Road 14 (R14) consists of the three sections of B152, B425, and Eppamulla- Pamunugama Road (Figure 20.4). RDA has completed the detailed design for B152 and according to this detailed design, the road will have high embankments with retaining walls and gabion installed throughout in order to protect residents from canal flooding. The cross section of B152 has been examined and it is recommended that it be utilized for the other two roads as well, except that embankments will not be necessary. Note that road widening will be carried out on either side of the existing road (Figure 20.7). Figure 20.4 Layout of R14 Cross Section The proposed right-of-way will have a two-lane carriageway with shoulders and foot paths on either side, which is in accordance with RDA’s detailed design. Drainage will be located at the edge of the road. The proposed cross section is as shown in Figure 20.6 and more detailed drawings can be found in Appendix 30. 20-4 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects 6.00 Figure 20.5 Existing Typical Cross Section (R14) 15.2 0.6 1.5 3.5 3.5 1.5 0.6 2.0 2.0 Draiange Shoulder Carriageway Shoulder Draiange Cycle Lane Cycle Lane Figure 20.6 Proposed Typical Cross Section (R14) (3) R20: Nugegoda - Katiya Junction – Pepiliyana Road Design Overview The detailed design for the widening of the Katiya Junction-Pepliyana Road section is already complete. Widening from Nugegoda to Katiya Junction should be designed to avoid any negative impacts on the adjacent railway line. After examining the requirements of the Nugegoda-Katiya Junction section and the completed detailed design of the cross section for the road from Katiya Junction to Pepliyana, it is recommended that the cross section be utilized throughout the proposed scheme. According to RDA, drainage should be located under the cycle lane in the areas where residents will not allow land acquisition for road widening. This project also covers a small bridge (Ratmalana Bridge) improvement at the south end of this section. The basic layout of R20 is shown in Figure 20.7. Figure 20.7 Layout of R20 Cross Section The proposed right-of-way will have a two-lane carriageway with a shoulder and foot path on either side in accordance with RDA’s detailed design. Drainage will be located at the edge of the road. The proposed typical cross section is as shown in Figure 20.9 and more detailed drawings can be found in Appendix 30. 20-5 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects 6.00 Figure 20.8 Existing Typical Cross Section (R20) 15.2 0.6 1.5 3.5 3.5 1.5 0.6 2.0 2.0 Draiange Shoulder Carriageway Shoulder Draiange Cycle Lane Cycle Lane Figure 20.9 Proposed Typical Cross Section (R20) Ratmalana Bridge The length of bridge crossing the Ratmalana River is only 18.0 meters. Therefore, the simple bridge of the PCT girder is considered. A lane width of 3.3 meters and shoulder width of 1.5 meters per direction are considered to be suitable considering the existing traffic condition. Table 20.3 Bridge Type Length Road Bridge Span Superstructure Substructure/Foundation (m) 1. Ratmalana 18.0 1 Span PC T Girder RC Abutment/Bored Pile Source: This Study (4) R21: Thalawathugoda - Pannipitiya Road Design Overview The detailed design for R21 has already been completed by RDA and should be utilized for the design of this study. The proposed section extends from Thalawathugoda to Pannipitiya, where there is an unused flyover that crosses the railway (Figure 20.10). 20-6 Urban Transport Development Chapter 20 of the Colombo Metropolitan Region Road Extension and Widening Projects Figure 20.10 Layout of R21 Cross Section The proposed right-of-way consists of a four-lane carriageway with a median and shoulder on either side in accordance with RDA’s detailed design. Drainage will be located at the edge of the road. The proposed typical cross section is as shown in Figure 20.12 and more detailed drawings can be found in Appendix 30. 9.00 1.00 3.50 3.50 1.00 Figure 20.11 Existing Typical Cross Section (R21) 21.80 0.90 3.50 3.50 1.20 3.50 3.50 0.90 2.40 2.40 Shoulder Carriageway Median Carriageway Shoulder Drainage Drainage Figure 20.12 Proposed Typical Cross Section (R21) (5) RWP2: Thalawathugoda - Koskadwila Road Design Overview This road is administered by the WPRDA and the design was prepared in discussions with this organization.

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