The Chennai Unified Metropolitan Transport Authority (CUMTA) has proposed developing the Grand Southern Trunk Road and Velachery-Tambaram Road as Model Urban Mobility Corridors under the second phase of its programme. The authority plans to prepare detailed project reports (DPRs) for the proposed stretches, with tenders expected to be invited this week. Under Phase 1, CUMTA has identified 25 km of Old Mahabalipuram Road (OMR), from Madhya Kailash to Kelambakkam, and 7.4 km of Pallavaram-Thoraipakkam Road, from Pallavaram Bridge to Thoraipakkam junction. The DPR tender for the two roads is being issued again after the earlier bid was cancelled because of technical issues. A pre-bid meeting for the fresh tender was held on Tuesday. The Phase-2 proposal also includes Taramani Link Road and the Marmalange Bridge-Wallajah Road. CUMTA said the final length of roads to be covered in this phase would be known after the tender was floated. The proposed corridors are intended to connect railway stations, MRTS stations, metro stations, bus terminals and bus stands, with the aim of improving last-mile connectivity and integration between transport modes. The DPRs will examine measures to promote walking and cycling, discourage private vehicle use, reduce idling at intersections and ease congestion. They will also address annual per capita greenhouse gas emissions from transport, while incorporating road safety measures and urban development alongside the road network. Planned improvements include uniform carriageways, green medians, dedicated service lanes, upgraded culverts and bridges, grade separators, pedestrian facilities, traffic-calming measures, green corridors, designated bus bays and stops, parking areas and cycling infrastructure. Public spaces beneath flyovers and grade separators, above subways and around roads integrated with parks will also be upgraded. CUMTA will prepare the DPRs, while the state highways department will implement the projects. Work on OMR and the radial road will begin after metro rail construction is completed, as carrying out upgrades earlier could result in damage to the improvements. The model corridor works are expected to take around two years.