IRC SP 69:2018 is the Indian Standard (IRC) for guidelines on traffic calming measures for safe mixed traffic. This IRC code provides comprehensive guidelines on traffic calming measures for safe mixed traffic environments. It covers the principles, types, design considerations, and evaluation of various measures aimed at reducing vehicle speeds, enhancing pedestrian and cyclist safety, and improving the overall quality of life in urban and suburban areas. The code emphasizes a holistic approach, integrating engineering, urban design, and community engagement.
Guidelines for the design, implementation, and evaluation of traffic calming measures to improve road safety and community livability in mixed traffic environments.
Key reference values — verify against the current code edition / project specification.
| Reference | Value | Clause |
|---|---|---|
| Subject | Traffic-calming measures for safe mixed traffic | Scope |
| Measures | Humps, tables, chicanes, narrowing, rumble strips | Toolbox |
| Objective | Lower speeds in vulnerable/residential zones | Why |
| Placement | Warned, lit, signed; not on high-speed through roads | Siting |
| Read with | IRC SP 88 (speed breakers) / IRC SP 44 | Cross-ref |
IRC SP 69 specifies guidelines on traffic calming measures for safe mixed traffic — design and implementation of traffic-calming interventions to reduce vehicle speed, manage conflicts between motorised and non-motorised users, and improve pedestrian / cyclist safety. The code recognises the Indian context of mixed traffic (cars + two-wheelers + bicycles + pedestrians + animal-drawn vehicles + auto-rickshaws + buses + trucks) and designs interventions that work across all user types.
Use IRC SP 69 when designing: - Traffic-calming for residential / mixed-use neighbourhoods - School / hospital / market zones - Smart-city street redesigns (Indore, Pune, Bhopal, Surat smart-city projects) - Slow-zone / 30 km/h zones in urban centres - Safety upgrades on accident-prone road sections - Tactical urbanism / pop-up traffic-calming pilots - Pedestrian-priority street redesigns (woonerf-style, complete streets)
The code goes beyond just speed breakers (IRC SP 88:2019) to cover the full traffic-calming toolkit: - Geometric calming (lane narrowing, chicanes, mini-roundabouts) - Vertical calming (speed humps, speed tables, raised crossings, raised intersections) - Surface treatment (rumble strips, textured pavement, coloured pavement) - Visual calming (gateways, planting, vertical elements) - Signage + markings - Time-based restrictions (no through-traffic, time-of-day closures) - Integration with cycle / pedestrian infrastructure
IRC SP 69 reflects modern urban traffic engineering thinking influenced by global best practice (UK, Netherlands, Germany Verkehrsberuhigung, US Complete Streets) adapted to Indian conditions.
1. Vertical deflection devices (most impactful): - Speed hump / speed bump (IRC SP 88:2019) — single hump - Speed table — flat-top hump, can be combined with raised crosswalk - Raised intersection — entire intersection raised to footpath level (signals priority for pedestrians) - Raised pedestrian crossing — speed table at marked crossing
2. Horizontal deflection devices: - Chicane — staggered horizontal alignment forces slow turning - Lateral shift — lane offset around bollards / planters - Mini-roundabout — small circle replaces signalled / uncontrolled intersection (forces low-speed circulation) - Pinch point — narrowing at strategic location, single-vehicle width passage
3. Lane modification: - Lane narrowing — reducing lane width from 3.5 m to 2.7-3.0 m (psychological speed control) - Edge friction — adding parking, planters, trees at carriageway edge (perceived narrower) - Centre-line removal — on residential streets to discourage two-lane operation
4. Surface treatment: - Rumble strips (IRC SP 88:2019 Type D) — audio-tactile warning - Coloured / textured pavement — visual cue at school / pedestrian zones - Imprint / brick pavement — slows vehicles via visual + texture
5. Visual / perceptual calming: - Gateway treatment at zone entry — sign + colour + texture indicating slow zone - Tree-lined / planter strips at edge — narrows visual width - Vertical signage / public art — slows visual perception - Reduced street lighting in residential zones (less highway-feel)
6. Time-based + access restrictions: - No through-traffic (residential streets via diagonal closures) - Truck restrictions (no HCV in school / hospital zones at certain times) - One-way conversion (eliminates head-on conflicts, reduces speed) - Time-of-day closures for pedestrian-only periods (market zones)
7. Pedestrian-priority interventions: - Pedestrian-only streets - Shared-space streets (woonerf) - Crossings (zebra, signal, pelican, raised, refuge island) - Footpath widening — taking carriageway space for pedestrians - Cycle tracks — segregated cycle facilities
Target speed by zone type:
| Zone | Target speed | Calming intensity | |---|---|---| | Residential street | 25-30 km/h | Moderate (humps, chicanes, lane narrowing) | | School zone (during school hours) | 25 km/h | High (humps, raised crossings, gateways) | | Hospital approach | 30 km/h | Moderate (humps, signage) | | Market / commercial street | 25 km/h | High (cushion humps, paving treatments) | | Mixed-use main street | 30-40 km/h | Moderate (corner build-outs, planters) | | Slow / 30 zone | 30 km/h area-wide | Multiple coordinated interventions | | Pedestrian-priority street | 10-15 km/h | High (shared-space design, no kerb separation) |
Spacing of vertical calming devices for sustained low speed: - 25 km/h target: humps every 50-80 m - 30 km/h target: humps every 80-120 m - 40 km/h target: humps every 120-200 m
Lane width for calming: - Standard urban lane: 3.5 m - Narrowed for calming: 2.7-3.0 m (still passable for buses / trucks) - Below 2.7 m: bus / truck conflicts; rare in mainstream design
Pedestrian crossing facilities: - Refuge island in crossings > 12 m wide: minimum 1.5 m - Zebra crossing width: minimum 4 m - Signal-controlled crossing: where ped count > 100/hr OR vehicle count > 1500 PCU/hr - Raised crossing (speed table): for ped-priority zones
Cycle infrastructure (where included): - Painted cycle lane: 1.5-2.0 m wide - Segregated cycle track: 2.0-3.0 m, raised or kerb-separated from carriageway - Cycle box at signal-controlled intersection: ahead-of-stop-line for cyclists
Effectiveness benchmarks (typical outcomes from implemented projects): - Single speed hump: 40-50 % reduction in 85th-percentile speed at hump; 20-25 % reduction over 200 m segment - Speed humps every 80 m: 30-40 % reduction in mean speed over zone - Lane narrowing: 5-15 % reduction in mean speed (less effective alone) - Combined treatments (hump + chicane + signage + planters): 50-60 % reduction
Enforcement: - Speed cameras in slow zones - Police presence at school zones during start / end times - Education + signage campaign
1. Single-intervention approach. One speed hump in isolation only slows traffic at that point; vehicles re-accelerate. Effective calming requires layered interventions over a zone. 2. Calming on emergency vehicle routes without consideration. Ambulances delayed, fire vehicles damaged. Use speed cushions (Type B per IRC SP 88) on EVRs. 3. No engagement with local community / users. Top-down calming installations met with vandalism, removal demands. Engage shopkeepers, residents, school principals before installation. 4. Inadequate signage / visibility. Calming devices (especially humps) invisible at night cause accidents. Mandatory marking + lighting. 5. Drainage neglected. Vertical interventions disrupt longitudinal water flow; pooling, pavement damage. Maintain cross-drainage continuity. 6. Calming measures inappropriate for road class. Speed humps on NH / expressway = catastrophic (not allowed per IRC SP 88). Calming is for urban / residential / school / hospital zones, not for high-speed corridors. 7. No pedestrian / cyclist provision. Slowing cars without providing safe pedestrian / cyclist facilities is half-measure; pedestrians still vulnerable to U-turns, illegal parking, etc. 8. Excessive friction-reduction. Decorative paving (cobblestone, brick) at high-speed location creates skid hazard. Match material to speed. 9. Installation without baseline + post-installation measurement. No way to evaluate effectiveness; cannot iterate. Always measure 85th-percentile speed before + after; track accident statistics. 10. No maintenance plan. Painted markings fade, planters die, signage falls. Calming requires ongoing maintenance budget. 11. Mini-roundabouts undersized for actual largest-vehicle. Bus / truck cannot negotiate; either climb the central island (damaging it) or block the intersection. Verify largest-vehicle turning template. 12. Time-based restrictions without enforcement. 'No trucks 8-10 AM' sign without police = ignored. Pair restriction with enforcement camera or physical barrier (rising bollard).
Traffic-calming planning cascade:
1. Problem identification — speed measurement, accident data, pedestrian complaints, school principal concerns, market trader feedback. 2. Zone definition — boundary of slow zone (typically a residential block or commercial cluster). 3. Stakeholder engagement — residents, traders, schools, transport operators, emergency services, police. 4. Diagnostic study: - Vehicle volume + composition - Speed (85th-percentile) - Accident pattern (collision diagram) - Pedestrian / cycle activity - Existing infrastructure (signage, markings, geometry) 5. Intervention design (IRC SP 69:2018): - Select from menu (humps, chicanes, lane narrowing, signage, gateways) - Coordinate interventions over zone - Maintain emergency vehicle access - Maintain bus accessibility - Pedestrian / cycle integration 6. Detailed design — drawings, BOQ, signage layouts, drainage check. 7. Tactical / pilot implementation (optional) — temporary materials (paint, planters, cones) for testing before permanent installation. 8. Permanent construction — humps, raised crossings, paving, signage. 9. Post-installation measurement — speed, accidents, user feedback. 10. Iteration — adjust if needed (additional interventions, modifications). 11. Maintenance — ongoing markings refresh, drainage cleaning, planter care.
Outcome metrics: - 85th-percentile speed reduction - Mean vehicle speed reduction - Accident count change (pre vs post) - Pedestrian / cycle activity increase - Resident satisfaction survey - Bus on-time performance maintained - Emergency vehicle response time maintained
IRC SP 69:2018 is the most current Indian standard for comprehensive traffic-calming design. Smart-city projects across India have adopted its principles; future revisions will likely add more digital infrastructure (smart-camera enforcement, adaptive signal control, real-time traffic management) integrations.