Traffic Signal Pole Height and Arm Length Selection Calculator
Introduction
Choosing the wrong pole height or arm length causes clearance problems or visibility issues. This guide gives the formulas and worked examples for typical urban and rural installations.
Mounting Height Formula
The signal head should be at least 5.0 m above the road surface for urban roads, 5.5 m for truck routes. The mounting height above the ground equals the signal head's bottom clearance plus the head's drop distance below the arm.
For a 300mm head with a 0.5 m drop below the arm: - Mounting height (underside of arm) = head drop + head height + head clearance - = 0.5 + 0.4 + 5.0 = 5.9 m above the road
GAOQIAO standard poles come in 5 m, 6 m and 7 m mounting heights. The 7 m pole is the standard for arm-mounted vehicle signals.
Arm Length Formula
The arm should extend over the centreline of the far lane. The arm length equals:
Arm length = half the lane count × lane width + kerb offset + signal head setback
For a 4-lane road (2 each direction) with 3.5 m lanes, 0.5 m kerb offset and 0.5 m setback: - Arm length = (4 × 3.5) / 2 + 0.5 + 0.5 = 7.0 + 1.0 = 8.0 m
GAOQIAO standard arm lengths are 3 m, 4.5 m, 6 m, 7.5 m and 9 m. Custom lengths available.
Worked Example
A 4-lane urban road (2 lanes each direction), 7 m kerb to centreline, requires: - Mounting height: 7 m (standard) - Arm length: 7 m + 1 m offset = 8 m (use 7.5 m standard arm) - Total pole height above ground: 7 m mounting height + arm rise + signal head height - Foundation: 1.5 m × 800 mm square
GAOQIAO supply a 7 m mounting height / 7.5 m arm pole with the matching foundation drawing.
Featured Products
GAOQIAO supplies vertical poles, signal arm poles and double-arm poles in standard and custom sizes. See the pole selection guide.
Conclusion
Mounting height = 5-5.5 m + drop. Arm length = half lane width + offsets. GAOQIAO supplies standard sizes covering most intersections and custom sizes for unusual cases. Send us your road width and approach speed for a pole recommendation.
Get a Quote
Email: sky-sale@njgq.net WhatsApp/Phone: +86-18805173545 Tel: +86-25-84471080
Frequently Asked Questions
What if my road is wider than the longest standard arm?
Use a double-arm pole (two short arms on one foundation) or a span wire across the road. GAOQIAO supplies both.
Can I get a custom arm length?
Yes. GAOQIAO supplies custom arm lengths up to 12 m for special projects. Add 2-4 weeks to the lead time.
What about vertical clearance for tall vehicles?
The pole must provide at least 5.0 m vertical clearance under the arm for urban roads, 5.5 m for truck routes. GAOQIAO pole drawings show the vertical clearance for each standard size.
Relevant GAOQIAO products
These public GAOQIAO catalogue pages are related to the guide. Open them for the representative description, then confirm the latest drawing and configuration before ordering.
- Traffic signal controllersWired and solar controllers with 6, 22, 44 and 56 output options.
- LED traffic signal heads200mm, 300mm and 400mm signal heads with MUTCD, EN12368, GB14886 compliance.
- Signal polesVertical, signal arm and double-arm poles for any intersection geometry.
- Spare parts and accessoriesSpare LED modules, lenses, visors, surge arrestors and anchor bolts.