IRC SP 40:2019 is the Indian Standard (IRC) for guidelines on measures for safety on existing two-lane national highways. This IRC code is a crucial reference for engineers tasked with enhancing the safety of existing two-lane National Highways. It outlines a systematic approach to accident analysis, identification of hazardous locations, and the implementation of a wide array of remedial measures. The guidelines cover geometrical improvements, traffic control devices, road furniture, and operational strategies. By adhering to these recommendations, engineers can significantly reduce accident frequency and severity, thereby improving the overall efficiency and user experience of these highways.
This IRC code provides comprehensive guidelines for identifying and implementing safety measures on existing two-lane National Highways. It focuses on addressing existing deficiencies and improving the safety of all road users, including drivers, pedestrians, and cyclists, on these vital transportation corridors.
Key reference values — verify against the current code edition / project specification.
| Reference | Value | Clause |
|---|---|---|
| Subject | Safety measures on existing two-lane National Highways | Scope |
| Approach | Identify hazard locations → engineering countermeasures | Method |
| Measures | Shoulder/markings/signs/black-spot treatment | Treatment |
| Tool | Road-safety audit / inspection driven | Process |
| Read with | IRC SP 88 (safety audit) / IRC SP 44 | Cross-ref |
IRC SP 40 specifies guidelines on measures for safety on existing two-lane National Highways — the systematic methodology for upgrading safety on existing 2-lane NH corridors that connect major cities + carry significant inter-state traffic but cannot be widened to 4-lane in the near term. India has ~50,000 km of 2-lane NHs; safety upgrades through this code provide cost-effective accident reduction without major reconstruction.
Use IRC SP 40 when: - Identifying safety improvements on existing 2-lane NH - Black spot treatment programmes - Targeted upgrades on accident-prone corridors - BOT contract safety performance requirements - State Road Safety Council action plans - Bharatmala safety component
Typical 2-lane NH safety issues: - Inadequate sight distance on curves / crests - Insufficient shoulders for emergency stopping - Missing / inadequate signage - Un-marked centre lines - Roadside hazards (trees, rigid posts) close to carriageway - Pedestrian + non-motorised traffic mixed with vehicle traffic - Inadequate intersection treatment - Absence of vehicular barriers on dangerous curves - Speed differential between heavy + light vehicles - Animal crossings
Coverage: - Existing condition assessment + safety audit - Engineering safety upgrades (geometric, signage, barriers) - Speed management - Pedestrian / VRU safety - Black spot treatment - Performance monitoring + iterative improvement
Engineering safety upgrades (per IRC SP 40):
| Upgrade | Specification | |---|---| | Hardened shoulders | Width: 1.5-3.0 m on each side; surface treatment | | Crash barriers (IRC:99:2018) | At dangerous curves, embankment > 3 m, structures | | Sight distance correction | Per IRC:66:1976; cut slope adjustment, vegetation clearing | | Centre line marking (IRC:35:2015) | Continuous double-line where overtaking unsafe; broken elsewhere | | Edge lining (white) | Mandatory on all 2-lane NHs | | Reflective road studs | Every 10-30 m typical | | Warning signs (IRC:67:2012) | At all hazards (curves, crests, intersections, bridges) | | Speed restriction signs | Per posted speed; enforcement essential | | Speed enforcement cameras | At black spots + village entries | | Lighting | Approach to village + intersection + bridge | | Bus stops (IRC 80:1981) | Lay-by type at safe locations | | Pedestrian crossings | Marked + signalised at village entries / school zones | | Vehicular underpass / overpass | At major settlements (avoid through-village traffic) |
Black spot identification + treatment: - Black spot: > 5 fatal accidents in 3 years on 500 m section, OR > 3 fatalities in single event - Treatment menu (cost-graded): - Signage + markings (cheapest; quick) - Geometric correction (longer; expensive) - Bypass / interchange (most expensive; major project)
Speed management: - Speed surveys at representative locations - 85th-percentile speed → set design speed - Speed limit posting + enforcement - Speed cameras at black spots - Calming measures at village entries (per IRC SP 88:2019)
Pedestrian / VRU safety: - Footpath in villages - Marked pedestrian crossings - Speed reduction at school zones (25-30 km/h) - Cycle track in heavy-cycle-traffic areas - Animal crossing structures (especially in wildlife areas)
Safety audit cadence: - Pre-construction (Stage 2) - Pre-opening (Stage 3) - Operational (Stage 4) — every 3-5 years - Post-incident — after major accident or change
Cost (typical 2026): - Standard safety upgrade per km: ₹5-15 lakh (signage, markings, road studs, edge lining) - Black spot treatment: ₹20-100 lakh per spot - Major intervention (interchange, bypass): ₹10-100+ crore
1. No comprehensive safety audit. Safety improvements ad-hoc; not based on data. Mandate systematic audit. 2. Black spots untreated for years. Continuing fatalities. Annual review + budget. 3. No vehicular barriers on dangerous curves. Run-off-road accidents fatal. Per IRC:99:2018. 4. Inadequate signage / faded markings. Drivers don't anticipate hazards. Periodic refresh. 5. No speed management. Speed limits ignored. Posted limits + enforcement + cameras. 6. Pedestrian + cyclist mixed with traffic. Vulnerable users at risk. Separated facilities + safe crossings. 7. Heavy + light vehicle speed differential. Frustration overtaking; collisions. Truck climbing lanes; passing places. 8. Inadequate hardened shoulder. Emergency stops on carriageway; rear-end risk. Provide 1.5-3 m hardened shoulder. 9. Roadside hazards (trees, rigid posts) close to carriageway. Vehicles strike fixed objects; fatal. Move + provide barriers. 10. No upgrade in budget cycle. Safety improvements deferred. Dedicated annual safety budget. 11. No post-treatment monitoring. Effectiveness of upgrade unknown. Track accident statistics post-treatment. 12. Public consultation skipped. Local opposition delays project. Engage communities.
2-lane NH safety upgrade cascade:
1. Existing condition assessment: - Accident statistics (3-year history) - Visual inspection - Traffic + speed surveys - Pedestrian / cyclist count - Sight distance verification 2. Black spot identification — accident frequency mapping. 3. Safety audit (Stage 4 — operational) by independent road safety engineer. 4. Upgrade prioritisation: - Quick wins: signage, markings, road studs - Black spot treatment - Geometric improvements - Major interventions (interchange, bypass) 5. Design (IRC SP 40 + companion codes) — engineering details. 6. Implementation — contractor work; quality acceptance per IRC SP 11. 7. Performance monitoring: - Accident statistics post-treatment - Speed compliance - Traffic flow + ride quality 8. Iteration — refine upgrades based on data; address new black spots.
India 2-lane NH context: - ~50,000 km of NH still 2-lane (out of total ~150,000 km NH) - Major safety improvement programme under Bharatmala + state initiatives - 4-laning + bypasses where traffic warrants; safety upgrades elsewhere - Motor Vehicles (Amendment) Act 2019 strengthened enforcement framework
IRC SP 40 provides the practical framework for upgrading safety on India's vast 2-lane NH network. Targeted, cost-effective improvements per this code can reduce fatalities by 30-50 % at modest investment vs full 4-laning.
| Parameter | IS Value | International | Source |
|---|---|---|---|