IRC 99:2018 is the Indian Standard (IRC) for tentative guidelines on the provision of speed breakers for control of vehicular speeds on minor roads. IRC 99:2018 specifies the design and application of speed breakers for traffic calming on Indian minor roads, urban streets, and sensitive areas. Speed breakers come in three forms: round-top humps (most common, 100 mm × 3.7 m parabolic, forces 20-25 kmph), flat-top raised tables (75-100 mm height, 3-5 m flat top, comfortable at 30-40 kmph), and rumble strips (25 mm × 300 mm, multiple strips for advance warning). Critically, IRC 99 explicitly PROHIBITS speed breakers on National Highways, State Highways, arterial roads, bus routes, and roads with gradient > 5% — these locations need different speed-management strategies. Amendment No. 1 (2021) added pre-formed rubber speed humps for temporary installations and smart speed breakers with illuminated markings for night visibility. Indian minor roads often have poorly-designed, unauthorized speed breakers — causing vehicle damage, passenger discomfort, and emergency vehicle delays. IRC 99 compliance requires proper authorization, design, signage, and maintenance. Speed breakers should be LAST RESORT for speed control; other measures (speed cameras, road narrowing, chicanes) often preferable.
Specifies design, location, and application of speed breakers (humps, rumble strips, raised tables) for traffic calming on minor roads, urban streets, school zones, hospital approaches, and accident-prone locations — NOT for major highways or arterials.
- Status
- Current
- Usage level
- Essential
- Domain
- Transportation — Traffic Engineering / Safety
- Type
- Guidelines
- Amendments
- Amendment No. 1 (2021) — pre-formed rubber speed humps for temporary installations; smart speed breakers with illuminated markings for night visibility
Also on InfraLens for IRC 99
Practical Notes
! Speed breakers on NH/SH are COMMON violations of IRC 99 — unauthorized installations by local authorities or villagers. These cause: vehicle damage, driver injuries, emergency vehicle delays, traffic disruption. Must be removed.
! Indian minor roads typically have too many speed breakers (3-10 per km) vs IRC 99 appropriate 1-3 per km. Excessive breakers cause driver fatigue, emergency delays, and increased emissions from braking-accelerating cycle.
! Round-top hump (100 mm × 3.7 m parabolic) is the workhorse design. Cheaper and simpler than raised tables. Forces 20-25 kmph speed — appropriate for schools, residential areas.
! Flat-top raised table (75-100 mm × 3-5 m flat): more comfortable for passengers at 30-40 kmph; also creates raised pedestrian crossing. Costs 2-3× round-top but worth for main commercial streets.
! Rumble strips (advance warning): 25 mm humps at 1 m spacing, 4-6 strips before main speed-control. Alerts driver of upcoming hazard WITHOUT forcing significant speed reduction. Good for highway approach zones.
! Critical dimensions: round-top must be parabolic (y = 100 × [1 - (2x/3.7)²]) not flat-sawtooth. Sawtooth profile causes bumper-scraping and vehicle damage. Contractor often mistakes — specify parabolic in drawings.
! Drainage cross-cut: essential on side of breaker. Without it, water pools at breaker — creates slippery ice-like condition in monsoon. Kills vehicles and causes accidents.
! Visibility before breaker: 30 m clear sight minimum. Warning sign at 30-50 m before. Yellow+black diagonal stripes on breaker surface. Reflective studs every 1 m for night.
! Signs and markings: often missing on Indian speed breakers — undermines effectiveness. Budget sign maintenance in annual budget.
! Pre-formed rubber speed humps (Amendment No. 1, 2021): quick installation for events, temporary road works, trial deployment. Cost ₹15-50k per hump. Used also on private roads (colonies).
! Smart speed breakers (Amendment No. 1, 2021): integrated LED lighting for night visibility (reduce accidents 30-40%). Powered by solar panel or underground cable. Cost ₹50k-2 lakh per breaker (vs ₹20-50k for standard).
! Bus routes: speed breakers UNACCEPTABLE. Cause passenger neck injuries, vehicle damage, reduced reliability. Bus routes need alternative speed control (cameras, narrowing, traffic calming circles).
! Emergency vehicle routes (near hospitals, fire stations): minimize speed breakers on approach. Use soft alternatives like speed tables or optical calming devices.
! Gradient > 5% roads: speed breakers PROHIBITED. Gravity amplifies effect — vehicle could go airborne. Use alternative control measures on hills.
! Height degradation: speed breakers wear from traffic — height reduces over time. Annual check; resurface when < 70 mm (round-top). Otherwise ineffective.
! Cost: round-top hump ₹15-30k installed (cement concrete); flat-top table ₹30-70k; rubber pre-formed ₹15-50k per section. Plus signage + marking ₹5-10k per site.
! Alternatives to speed breakers: speed cameras (₹5-15 lakh setup, e-challan revenue covers), road narrowing (chicanes), painted speed illusions (Amsterdam lines), raised crossings, speed-aware traffic signals.
! Removal of illegal speed breakers: PWD/NHAI responsibility. Political will often lacking — vested local interests. Systematic survey and removal + penalty for unauthorized installations needed.
! School zones: mandatory IRC 99 speed breakers within 100 m of school entry. Combined with crossing signals + speed camera. Reduces school-zone accidents 60-80%.
! Future: connected vehicles with V2X can be signaled of speed breaker zones, adjust speed automatically. Physical breakers may become obsolete over 15-20 years.