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IRC 93 : 1985Guidelines on Design and Installation of Road Traffic Signals

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IRC 93:1985 is the Indian Standard (IRC) for guidelines on design and installation of road traffic signals. IRC 93:1985 is the foundational code for traffic signal design and installation in India — covering when signals are justified (warrants), how to time them (cycle length, green time, intergreen), signal phases, pedestrian accommodations, vehicle-actuated and coordinated signals, and maintenance. Indian urban intersections are notoriously over-saturated; proper signal design is critical to urban mobility. The code specifies Webster's cycle-length formula, green-time optimization, and phase selection. Amendment No. 2 (2018) added audible signals for visually impaired pedestrians and vehicle preemption for emergency vehicles. For smart-city ITS systems (Bhopal, Surat, Indore), IRC 93 remains the baseline while ITS-specific codes (IRC SP 88, CCS 4) handle adaptive signals, predictive control, and real-time optimization. Modern installations use 300 mm LED lenses per IS 14458, countdown pedestrian signals, and centralized area-traffic-control systems.

Provides guidelines for the warrants, design, installation, timing, and operation of traffic signals at road intersections — fixed-time signals, vehicle-actuated signals, and coordinated signal systems.

Quick Reference — Top IRC 93:1985 Values

Key parameters for signal warrants, cycle time design, pedestrian facilities, and physical installation of signal heads and posts.

✓ Verified 2024-05-21

Reference	Value	Clause
Warrant 1: Min. Vehicular Volume (Major Road)— Total of both approaches for any 8 hours of an average day.	750 veh/hr	Cl. 3.2
Warrant 1: Min. Vehicular Volume (Minor Road)— From the higher volume side approach for the same 8 hours.	250 veh/hr	Cl. 3.2
Warrant 2: Interruption of Traffic (Major Road)— Total of both approaches for any 8 hours of an average day.	1000 veh/hr	Cl. 3.3
Warrant 2: Interruption of Traffic (Minor Road)— From the higher volume side approach for the same 8 hours.	100 veh/hr	Cl. 3.3
Warrant 3: Min. Pedestrian Volume— Crossing the major street for any 8 hours of an average day.	150 pedestrians/hr	Cl. 3.4
Warrant 4: Accident Experience— Reportable accidents of a type correctable by signals in a 12-month period.	≥ 5 per year	Cl. 3.5
Typical Cycle Time Range— Shorter cycles are generally preferred to reduce delay.	40 - 120 s	Cl. 4.3.1
Maximum Practical Cycle Time— Exceeding this can lead to excessive delays and driver frustration.	120 s	Cl. 4.3.1
Lost Time per Phase— Accounts for reaction time and time for vehicles to accelerate/decelerate.	2 - 4 s	Cl. 4.3.2
Amber (Yellow) Period Duration— For approach speeds up to 60 km/h.	3 s	Cl. 4.4.1
Amber Period (High Speed)— For approach speeds exceeding 60 km/h.	4 s	Cl. 4.4.1
Minimum Vehicular Green Time— Ensures adequate time for a queue of vehicles to start moving.	10 s	Cl. 4.3.4
Minimum Pedestrian Green (Walk) Period— Allows pedestrians to react and step off the kerb.	7 s	Cl. 4.6.3
Design Pedestrian Walking Speed— Used to calculate the pedestrian clearance (flashing green man) time.	1.2 m/s	Cl. 4.6.3
Standard Signal Lens Diameter— For normal visibility conditions and approach speeds.	200 mm	Cl. 5.2.1
Large Signal Lens Diameter— Used for high-speed approaches (>60 km/h) or wide carriageways.	300 mm	Cl. 5.2.1
Minimum Signal Visibility Distance— Unobstructed view of the signal face for an approaching driver.	50 m	Cl. 5.4.1
Mounting Height of Primary Signal— Height from carriageway to the bottom of the signal housing.	2.5 m - 3.0 m	Cl. 5.4.2
Vertical Clearance for Overhead Signals— Clearance from carriageway to the bottom of the signal housing.	5.5 m - 7.0 m	Cl. 5.4.2
Lateral Placement from Kerb Line— Distance from kerb to the nearest part of the signal assembly.	0.3 m - 1.5 m	Cl. 5.4.3
Pedestrian Signal Mounting Height— Height from footpath to the bottom of the signal housing.	2.1 m - 2.4 m	Cl. 5.6.2

⚠ Verify against the latest BIS/IRC publication and project specifications. Amendment Slips may modify values.

Overview

Status: Current
Usage level: Essential
Domain: Transportation — Traffic Engineering
Type: Guidelines
Amendments: Amendment No. 1 (2002) — added vehicle-actuated signals and coordinated systems; Amendment No. 2 (2018) — audible signals for visually impaired, emergency vehicle preemption, LED lens standards

Typically used with

IRC 35 IRC 67 IRC 103 IS 14458

Also on InfraLens for IRC 93

9Key values 5Tables 15FAQs

Practical Notes

! Warrant analysis is often skipped in India — signals installed for political/convenience reasons at junctions not meeting IRC 93 thresholds. Under-warranted signals create unnecessary delay and red-light running.

! Cycle lengths in Indian cities often exceed 120 seconds (IRC max) due to approach volumes — leads to pedestrian impatience and crossing during red. Consider grade separation or re-routing instead.

! Left-turn phasing in India is under-utilized — Indian practice is often permissive left (through general phase) which causes conflicts. Dedicated left-turn phase where sight lines are poor or volume > 150 vph.

! Pedestrian push-buttons: provided per IRC 93 but often ignored by pedestrians or broken. Better practice: automatic pedestrian phase every cycle at high-volume intersections.

! Countdown timers (pedestrian and vehicle) significantly improve compliance — vehicles don't accelerate toward ends of green, pedestrians don't start crossing in late don't-walk. Cost ₹5-10k per timer.

! Vehicle-actuated signals need good loop detector maintenance — embedded loops fail when pavement is resurfaced without coordination. Radar or video detection is more robust for retrofits.

! Coordination (progressive signals) works well on arterials with consistent spacing 200-400 m. Spacing > 600 m makes coordination infeasible without significant delay.

! Emergency vehicle preemption: transponder-based systems (fire trucks, ambulances) reduce response time by 15-25%. Cost ₹1-3 lakh per intersection but saves lives.

! Signal maintenance is routinely underfunded. Urban bodies allocate 2-5% of traffic budget for maintenance vs needed 10-15%. Results in dark/faulty signals.

! Audible signals (Amendment No. 2) are now mandatory at intersections with pedestrian volumes > 500/hour — important for visually impaired accessibility per Persons with Disabilities Act 2016.

! Power supply: UPS backup 4-8 hours minimum for urban signals. Without this, power cuts create chaos. Solar-battery systems increasingly viable for off-grid intersections.

! Signal pole location: maintain 1.0 m setback from kerb to prevent vehicle impact damage. Breakaway designs for high-speed roads > 50 kmph.

! LED vs incandescent: LEDs (per IS 14458 Amendment 2) consume 80% less power, last 5-10× longer, provide higher intensity — all-LED installation is now default for new signals.

! Adaptive signals (SCATS, SCOOT, adaptive signal control) use real-time traffic data to optimize. Installed in many Indian metros now; IRC 93 + IRC SP 88 govern design.

! Interlocking with traffic police (especially for weekends/holidays/protests) — manual override capability required per Clause 11. Police officer should be able to take over from signal controller.

! For smart city ITS deployments (Surat, Indore, Bhopal), area traffic control centers manage 20-100 intersections coordinatively. Adopted globally best practices integrated into IRC 93 provisions.

! Signal design life: controller ~10-15 years, lens housings ~20 years, poles ~30+ years. Budget replacement proactively; 'run to failure' creates sudden intersection blackouts.

! Traffic signal counts: Mumbai ~4,500 signals, Delhi ~3,200, Bangalore ~2,800, Chennai ~1,500, Hyderabad ~1,200 — a vast operational footprint requiring continuous management.

! Signal removal / replacement with roundabout: at intersections with volume-to-capacity ratio < 0.6 and space available, roundabouts often outperform signals. Consider IRC 11 (rotary) as alternative.

! CCTV integration at signals: violation detection (red-light running, lane discipline) increasingly used for e-challan systems. Cost ₹2-5 lakh per intersection for camera + OCR system.

Frequently referenced clauses

Cl. 2 — Warrants (when signals are justified): vehicular volume warrant (600+ vph on major approach), pedestrian warrant (150+ pedestrians/hr), accident warrant (5+ accidents/year), progressive movement warrant, coordinated system warrant

Cl. 3 — Intersection geometry prerequisites: adequate approach widths, visibility triangles, stopping sight distance, pedestrian refuges, turning lane geometry

Cl. 4.1 — Signal phases: 2-phase (simple), 3-phase (with left-turn separation), 4-phase (with dedicated pedestrian phase or right-turn protection)

Cl. 4.2 — Cycle length: minimum 40 seconds, maximum 120 seconds. Optimum typically 60-90 seconds for urban intersections. Longer cycles reduce capacity for pedestrians

Cl. 4.3 — Green time allocation: by Webster's formula C = (1.5L + 5) / (1 - Y) where C = optimum cycle, L = lost time per cycle, Y = sum of critical flow ratios

Cl. 5 — Intergreen (amber + all-red): 3-6 seconds amber + 1-2 seconds all-red, total 4-7 seconds. Longer for larger intersections (widths > 15 m)

Cl. 6 — Pedestrian phases: minimum green 4 seconds + flashing don't-walk 4 seconds per 15 m crossing distance + 1.2 m/s walking speed

Cl. 7.1 — Signal head mounting: 2.4 m minimum height above road, 5.0 m for overhead pole-mounted, clear visibility from 60 m approach

Cl. 7.2 — Lens size and colour: 300 mm dia lens minimum for major intersections; red, amber, green LEDs per IS 14458

Cl. 8 — Vehicle-actuated signals: induction loop detectors on each approach; extend green on detection; max/min green times

Cl. 9 — Coordinated signals (progressive): offset green times along arterial to allow platooned flow. Offset = intersection distance / design speed

Cl. 10 — Pedestrian signals: separate pedestrian signal heads at each crossing; audible signals for visually impaired (per Amendment 2); countdown timers for clarity

Cl. 11 — Emergency vehicle preemption: priority green for fire, ambulance, police; transponder-based or manual override

Cl. 12 — Signal controller: cabinet-mounted at intersection; solid-state controller with backup battery/UPS for power outages

Cl. 13 — Maintenance: monthly inspection, annual calibration, lamp replacement at 80% rated life, spare parts stock

Updates & Amendments1 amendment

2002Amendment No. 1 (2002) — added vehicle-actuated signals and coordinated systems; Amendment No. 2 (2018) — audible signals for visually impaired, emergency vehicle preemption, LED lens standards

Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.

traffic signalsintersectionsignalizationtimingcycle lengthITSIRC

Engineer's Notes

In Practice — Editorial Commentary

When IRC 93 is your governing code

IRC 93:1985 is the guideline for design + installation of road traffic signals at urban + sub-urban intersections, pedestrian crossings, and special locations. Traffic signals coordinate vehicle + pedestrian movements at conflicting flows, reducing congestion + collision risk. India's urbanisation has driven a 4-5× growth in signalised intersections over the past 15 years.

Use IRC 93 when: - Designing new traffic signal at urban intersection - Modifying / upgrading existing signal (timing, controller, equipment) - Pedestrian crossing signal installation - School zone signal - Adaptive / smart signal upgrade (V2X, AI-based) - Signal warrant analysis (do we even need a signal?) - Forensic investigation of signal-related accidents - Coordinating signals along corridor (green wave)

Why signals matter: - Manage conflicting traffic flows safely - Provide pedestrian / cyclist refuge - Optimise capacity at intersections - Reduce delay + fuel consumption (when timed correctly) - Enforce right-of-way (no driver discretion)

Signal types: - Fixed-time: same cycle every time (basic; suburban + low-volume urban) - Vehicle-actuated: detector senses vehicles + adjusts timing - Coordinated: corridor-level coordination for green wave - Adaptive (smart): real-time optimisation per traffic flow (modern best practice)

Warrant for signalisation: - Vehicle volume threshold: 600+ veh/hour total entering all approaches - Pedestrian crossings: 150+ peds/hour + < 60 gaps/hour - Accident history: 5+ accidents per year amenable to signal - School zone: per local authority assessment - Emergency vehicle priority crossing

Reference values you'll actually use

Signal design parameters (per IRC 93):

Cycle time: - Minimum: 30 sec (low volume) - Maximum: 120 sec (high volume) - Typical: 60-90 sec - Pedestrian: 8-12 sec walk + 4-8 sec clearance

Phase design: - 2-phase: simple T-junction - 3-phase: 4-way without separate left turn - 4-phase: with protected left turn / pedestrian phase - 6+ phase: complex multi-junction

Yellow change interval: - 3-5 seconds (typical 3-4 sec) - Calculated from approach speed + reaction time + braking

All-red clearance: - 1-3 seconds (clears vehicles already in intersection)

Signal head specifications: - LED preferred (energy efficient + bright + long life) - 200 mm or 300 mm lens diameter (300 mm for major intersections) - 3 aspects (red / yellow / green) for vehicles - 2 aspects (walk / don't walk) for pedestrian - Visibility range: > 100 m for major intersection

Mounting: - Pedestal mounted: 2-3 m height - Mast arm mounted: 5-7 m height across road - Overhead gantry: for multi-lane wide intersections - Setback from kerb: 0.5-1.0 m

Detector types: - Inductive loop: in-pavement; reliable but disturbs surface - Magnetometer: surface-mounted; less invasive - Video detection: camera + AI; modern + flexible - Radar / LIDAR: highway / high-speed locations

Controller cabinet: - IP65 rated; weather-protected - Standard NEMA TS-2 or Indian equivalent - Battery backup: 4-8 hours - Modem for remote monitoring (smart corridor)

Pedestrian timing calculation: - Walking speed: 1.2 m/s for general; 1.0 m/s for elderly / school zones - Crossing distance: from kerb to median or far kerb - Walk time: distance / walking speed + 5 sec clearance

Cost per signal (2026): - Basic fixed-time: ₹3-6 lakh per junction - Vehicle-actuated: ₹6-12 lakh - Adaptive / smart: ₹15-30 lakh per junction - Annual maintenance: ₹50K-1.5L per junction - Power: 50-200 W per signal head; ₹500-2000/month

Performance benchmarks: - Average delay reduction: 20-40 % vs unsignalised - Right-angle crash reduction: 50-70 % - Pedestrian safety improvement: 70-80 % - Traffic capacity: 600-1800 veh/hour per lane (signalised)

Companion codes (must pair with)

IRC 35 — code of practice for road markings (works with signal at junction).
IRC 67 — road signs (see IRC 67:2012).
IRC SP 41 — guidelines on design of at-grade intersections.
IRC SP 87 — manual on traffic studies (signal warrants).
IRC SP 90 — manual for road safety audits.
IRC SP 88 — manual on road safety audit.
IRC 86 — geometric design standards (see IRC 86:2018).
IRC 92 — interchanges in urban areas (see IRC 92:2017).
IRC 70 — mixed traffic in urban areas (see IRC 70:2017).
IRC SP 64 — lighting on highways.
IRC SP 73 — two-laning of highways with paved shoulders.
MoRTH Specifications.
MUTCD (Manual on Uniform Traffic Control Devices, USA — global reference).
IS 11923 — traffic signal controller.
IS 9559 — pedestrian signal.
DEERY (Indian Roads Congress Emergency Regulation Yardstick) — for emergency response signals.
Smart Cities Mission ITS guidelines.

Common pitfalls / what reviewers flag

1. No warrant analysis before installation. Signal where roundabout / yield works better. Apply warrant per IRC 93. 2. Cycle time too long. Excessive delay; drivers run reds. Optimise to 60-90 sec. 3. Cycle time too short. Insufficient pedestrian crossing time. 8-12 sec walk minimum. 4. No left turn protection. Conflict with through traffic; right-angle crashes. Add protected left turn phase. 5. Yellow interval too short. Drivers can't safely stop or clear; rear-end crashes + red running. 3-5 sec; calc per approach speed. 6. No all-red clearance. Vehicles still in intersection during next phase; T-bone risk. 1-3 sec all-red. 7. Signal head visibility blocked. Trees, building, parked vehicles; driver doesn't see signal. Ensure 100 m+ sight line. 8. Pedestrian signal not provided. Cars assume right-of-way; pedestrian risk. Provide ped signal at all signalised intersections. 9. Detector failure not detected. Signal stays in default; massive delay. Remote monitoring + alarm. 10. No emergency vehicle priority. Ambulance / fire stuck at red. Pre-emption system + dedicated phase. 11. No coordination between adjacent signals. Stop at every signal; drivers frustrated. Coordinate corridor for green wave. 12. No backup power. Signal off in power outage; chaos. Battery backup 4-8 hours. 13. No retro-reflective signage / road marking. Night visibility low. Add reflective signs + raised markers. 14. Signal pole damaged in accident not replaced. Continued risk. Periodic inspection + repair. 15. No ITS integration. Modern smart corridor capability missed. Plan for V2X / adaptive signal upgrade.

Where it sits in urban traffic management

Signalisation lifecycle:

1. Site assessment — traffic count, peak hour volume, accident history, pedestrian flows. 2. Warrant analysis — does this site need a signal per IRC 93? 3. Geometric design — intersection layout, lane assignment, turn pockets, median. 4. Signal design: - Phase design (2 / 3 / 4 / 6 phase) - Cycle time + split optimisation - Yellow + all-red intervals - Pedestrian timing - Coordination with adjacent signals 5. Equipment specification: - Signal heads (LED, 300 mm) - Controller cabinet (NEMA TS-2) - Detectors (loop / video) - Battery backup - Communication (4G / fibre) 6. Installation: - Civil works (signal pole foundation, conduit, cabling) - Electrical (power supply, earthing) - Equipment installation + commissioning - Testing (timing, detector, fail-safe) 7. Activation — soft launch (yellow flash) + go-live. 8. Operations: - Daily monitoring (traffic operations centre) - Periodic timing optimisation - Detector maintenance - Lamp / LED replacement 9. Annual review — accident data, traffic growth, timing reoptimisation. 10. Upgrade — every 8-12 years to next generation (e.g., adaptive, V2X).

Smart city integration: - Adaptive signal control (SCATS, SCOOT, Indian-developed CoSiCoSt) - Centralised traffic operations centre - V2X (vehicle-to-infrastructure) communication - Pedestrian safety integration with mobile app - Emergency vehicle pre-emption - Integration with parking, public transit

India context: - Most signal installations were fixed-time (1990s-2010s) - Smart cities mission accelerated adaptive signals (2015 onwards) - 50,000+ signalised intersections nationwide; ~15-20 % adaptive - Major cities (Bangalore, Delhi, Mumbai, Hyderabad) have integrated traffic management

IRC 93:1985 is dated; must supplement with modern ITS guidelines for smart corridor implementation. The fundamental signal design principles remain valid; technology + integration have advanced significantly.

International Equivalents

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Key Values9

Quick Reference Values

min cycle sec40

max cycle sec120

optimum cycle urban sec60-90

amber sec3-6

all red sec1-2

pedestrian walk sec min4

walking speed ms1.2

signal head height m2.4

overhead height m5.0

Key Formulas

Webster's optimum cycle: C = (1.5 × L + 5) / (1 - Y), where L = lost time (sec/cycle), Y = sum of critical flow ratios

Green time for phase i: g_i = (C - L) × y_i / Y, where y_i = critical flow ratio for phase i

Pedestrian crossing time: P = 4 + (W / 1.2) seconds, where W = crossing width in metres

Tables & Referenced Sections

Key Tables

Table 2.1 — Warrants summary (vehicular, pedestrian, accident, progressive, coordinated)

Table 4.1 — Minimum and maximum cycle lengths by intersection type

Table 5.1 — Intergreen time vs intersection width

Table 6.1 — Pedestrian signal timings vs crossing distance

Table 7.1 — Signal head specifications vs mounting location

Frequently Asked Questions15

When is a traffic signal warranted?+

Per Clause 2 warrants: (1) vehicular volume warrant (600+ vph on major approach for 8+ hours), (2) pedestrian warrant (150+ ped/hr crossing), (3) accident warrant (5+ injury accidents/year), (4) progressive movement warrant, (5) coordinated system warrant. At least one must be met to justify signalization.

What is the minimum and maximum cycle length?+

Per Clause 4.2: minimum 40 sec, maximum 120 sec. Optimum 60-90 sec for urban conditions. Longer cycles reduce pedestrian service; shorter cycles reduce vehicle throughput. Use Webster's formula for optimization.

How is cycle length calculated?+

Webster's formula (Clause 4.3): C = (1.5L + 5) / (1 - Y), where L = lost time per cycle (typically 10-15 sec), Y = sum of critical flow ratios (v/s) across phases. For example, if L = 12 sec and Y = 0.75, optimum cycle = (18 + 5) / 0.25 = 92 seconds.

What is intergreen time?+

Per Clause 5: intergreen = amber + all-red, typically 4-7 seconds. Amber (yellow) is 3-6 sec warning signal; all-red is 1-2 sec clearance for vehicles in intersection. Longer intergreen for wider intersections.

How do I design pedestrian signal timing?+

Per Clause 6: walk green minimum 4 sec + flashing don't-walk for clearance = 4 + (W / 1.2) seconds where W is crossing width in metres. For a 15 m crossing: 4 + 12.5 = 16.5 sec total pedestrian phase. Widened crossings need longer pedestrian green.

Are LED signals acceptable per IRC 93?+

Yes — Amendment No. 2 (2018) formally adopts LED lens signals meeting IS 14458. LEDs offer 80% energy savings, 5-10× longer life, higher intensity. Default choice for all new installations and retrofits.

What is the recommended signal head height?+

Per Clause 7.1: 2.4 m minimum from road surface for pole-mounted; 5.0 m for overhead gantry-mounted. Higher mounting improves visibility from further back. Use overhead mounting on multi-lane roads.

Are audible pedestrian signals mandatory?+

Per Amendment No. 2 (2018): mandatory at intersections with pedestrian volumes > 500/hour. Encouraged elsewhere. Aligns with Persons with Disabilities Act 2016. Standard audible signals use distinctive tones for different phases.

How does emergency vehicle preemption work?+

Per Clause 11: transponder on emergency vehicle communicates with intersection controller; controller gives priority green to vehicle's approach. Used in metros (Mumbai, Delhi) for fire/ambulance/police. Reduces response time 15-25%.

What is a coordinated signal system?+

Per Clause 9: signals along an arterial have synchronized green phases offset by travel time = spacing / design speed. A platoon of vehicles can pass through multiple signals without stopping, reducing delay. Typical for arterial corridors with spacing 200-400 m.

When to use adaptive signals (SCATS/SCOOT) vs fixed-time?+

Adaptive signals optimize timing real-time based on traffic flow. Justified for corridors/networks with demand > 800 vph (versus fixed-time cycle adequate for < 500 vph). Cost ₹5-15 lakh per intersection vs ₹1-2 lakh for fixed-time.

What about vehicle-actuated signals?+

Per Clause 8: loop detectors sense vehicles and extend/terminate green phases adaptively. Works well for low-volume side streets where fixed-time would allocate unused green. Requires detector maintenance (loops, radar, or video).

Can traffic signal be replaced by roundabout?+

For intersections with volume-to-capacity ratio < 0.6 and adequate space: roundabouts (IRC 11) often outperform signals — less delay, lower maintenance, no power needed. For oversaturated intersections (v/c > 0.8), signals still better. Consider in DPR stage.

What maintenance is required per IRC 93?+

Per Clause 13: monthly visual inspection, annual calibration, lamp replacement at 80% rated life (~2 years for incandescent, 8-10 for LED), spare parts stock at control room. Full re-timing annually based on current traffic counts.

Do I need signal design consultant or can municipal engineer do it?+

For simple 2-4 phase fixed-time signals: municipal traffic engineer can design per IRC 93. For complex coordinated systems, adaptive controllers, smart city ITS integration: specialized consultant required (typical fee ₹50k-5 lakh per intersection).

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IRC 93 : 1985Guidelines on Design and Installation of Road Traffic Signals

PDF Google Compare IRC Portal

Link points to Internet Archive / others. Not hosted by InfraLens. Details

International Comparison — Coming Soon

CurrentEssentialGuidelinesTransportation · Traffic Engineering

PDF Google Compare IRC Portal

Link points to Internet Archive / others. Not hosted by InfraLens. Details

Quick Reference — Top IRC 93:1985 Values

Key parameters for signal warrants, cycle time design, pedestrian facilities, and physical installation of signal heads and posts.

✓ Verified 2024-05-21

Reference	Value	Clause
Warrant 1: Min. Vehicular Volume (Major Road)— Total of both approaches for any 8 hours of an average day.	750 veh/hr	Cl. 3.2
Warrant 1: Min. Vehicular Volume (Minor Road)— From the higher volume side approach for the same 8 hours.	250 veh/hr	Cl. 3.2
Warrant 2: Interruption of Traffic (Major Road)— Total of both approaches for any 8 hours of an average day.	1000 veh/hr	Cl. 3.3
Warrant 2: Interruption of Traffic (Minor Road)— From the higher volume side approach for the same 8 hours.	100 veh/hr	Cl. 3.3
Warrant 3: Min. Pedestrian Volume— Crossing the major street for any 8 hours of an average day.	150 pedestrians/hr	Cl. 3.4
Warrant 4: Accident Experience— Reportable accidents of a type correctable by signals in a 12-month period.	≥ 5 per year	Cl. 3.5
Typical Cycle Time Range— Shorter cycles are generally preferred to reduce delay.	40 - 120 s	Cl. 4.3.1
Maximum Practical Cycle Time— Exceeding this can lead to excessive delays and driver frustration.	120 s	Cl. 4.3.1
Lost Time per Phase— Accounts for reaction time and time for vehicles to accelerate/decelerate.	2 - 4 s	Cl. 4.3.2
Amber (Yellow) Period Duration— For approach speeds up to 60 km/h.	3 s	Cl. 4.4.1
Amber Period (High Speed)— For approach speeds exceeding 60 km/h.	4 s	Cl. 4.4.1
Minimum Vehicular Green Time— Ensures adequate time for a queue of vehicles to start moving.	10 s	Cl. 4.3.4
Minimum Pedestrian Green (Walk) Period— Allows pedestrians to react and step off the kerb.	7 s	Cl. 4.6.3
Design Pedestrian Walking Speed— Used to calculate the pedestrian clearance (flashing green man) time.	1.2 m/s	Cl. 4.6.3
Standard Signal Lens Diameter— For normal visibility conditions and approach speeds.	200 mm	Cl. 5.2.1
Large Signal Lens Diameter— Used for high-speed approaches (>60 km/h) or wide carriageways.	300 mm	Cl. 5.2.1
Minimum Signal Visibility Distance— Unobstructed view of the signal face for an approaching driver.	50 m	Cl. 5.4.1
Mounting Height of Primary Signal— Height from carriageway to the bottom of the signal housing.	2.5 m - 3.0 m	Cl. 5.4.2
Vertical Clearance for Overhead Signals— Clearance from carriageway to the bottom of the signal housing.	5.5 m - 7.0 m	Cl. 5.4.2
Lateral Placement from Kerb Line— Distance from kerb to the nearest part of the signal assembly.	0.3 m - 1.5 m	Cl. 5.4.3
Pedestrian Signal Mounting Height— Height from footpath to the bottom of the signal housing.	2.1 m - 2.4 m	Cl. 5.6.2

⚠ Verify against the latest BIS/IRC publication and project specifications. Amendment Slips may modify values.

Overview

Status: Current
Usage level: Essential
Domain: Transportation — Traffic Engineering
Type: Guidelines
Amendments: Amendment No. 1 (2002) — added vehicle-actuated signals and coordinated systems; Amendment No. 2 (2018) — audible signals for visually impaired, emergency vehicle preemption, LED lens standards