Guidelines on Design Criteria and Pavement Type for Service Roads and Slip Roads in National Highway Projects

On November 3rd, 2025, the Ministry of Road Transport & Highways issued a circular (RW/NH-33044/33/2025-S&R(P&B), Computer No. 254799, 121.2.55) addressing the Chief Secretaries of all State Governments/UTs, the Principal Secretaries/ Secretaries of all States/ UTs Public Works Department/Road Construction Department/ Highways Department, the Chairman of the National Highways Authority of India (G-5 & 6, Sector-10, Dwarka, New Delhi-110 075), the Managing Director of NHIDCL (World Trade Centre, New Delhi-110029), the Director General (Border Roads) (Seema Sadak Bhawan, Ring Road, New Delhi-110 010), all Engineers-in-Chief and Chief Engineers of Public Works Department of States/UTs/ Road Construction Department/ Highways Departments, the Secretary General of the Indian Roads Congress, the Director of IAHE Noida, UP, and all CE-ROS, ROs and ELOs of the Ministry. The circular provides guidelines on design criteria and pavement type for service roads and slip roads in National Highway projects. These guidelines aim to ensure uniformity, serviceability, and durability, addressing issues of delayed projects, heavy traffic, and premature deterioration of service roads. Key directives include: * **Design Life:** The design life of service/slip roads (nSR) should be calculated as the sum of the project construction period (ncons) and a fixed period (nres) of 6 years for flexible/composite/rigid pavements. * **Design Traffic:** The design should use the same base traffic, growth rate, and vehicle damage factor (VDF) as the main carriageway, but limited to the design life specified. For flexible pavements, the design should be based on cumulative traffic expressed in million standard axles (MSA), with a minimum design for 20 MSA if calculated MSA is less than 20. The bituminous binder course must be at least 60 mm, and the bituminous wearing course must be at least 40 mm. Rigid pavements should be designed based on design life and cumulative fatigue/erosion criteria as per IRC: 58. * **Pavement Type:** Rigid pavements should be used in high rainfall areas (annual rainfall > 1500 mm), water-logging prone areas, urban areas, industrial zones, defence areas, and roads connecting to economic corridors, SEZ, and mining areas. Where main carriageway is with rigid type pavement, service road and slip road preferably be of rigid type pavement. Flexible pavements should be used in all other locations. * **Drainage:** All service/slip roads must have adequate drainage as per IRC standards. They should be completed before the main carriageway work and maintained accordingly, with restoration after opening traffic on the main carriageway. Appropriate modifications should be incorporated into RFP and relevant schedules. The guidelines can be adopted for ongoing projects with the approval of the Competent Authority. The contents of the circular must be brought to the attention of all concerned for immediate compliance. For further information, contact Akil Ahmad, Superintending Engineer, (S&R) for DG (RD) & SS.

Key Entities Referenced