Traffic light pole selection starts with the intersection layout, signal head weight, mounting height and arm length. A vertical pole carries one signal head, a signal arm pole reaches out over the lane, and a double-arm pole covers opposing approaches from one foundation.
Pole type comparison
| Pole type | Typical use | Mounting height | Arm length | Signal heads |
|---|---|---|---|---|
| Vertical pole | Pedestrian, side-road, school zone | 3-5 m | 0 m | 1-2 |
| Signal arm pole | Single vehicle lane approach | 5-7 m | 3-6 m | 1-3 |
| Double-arm pole | 4-way intersection or two-way coverage | 6-7.5 m | 2 x 3-6 m | 2-6 |
| High-mount pole | Highway, high-speed approach | 7-9 m | 6-12 m | 2-4 |
1. Why the pole type matters
The pole supports the signal head, resists wind load, and positions the signal over the correct lane. Choosing the wrong pole causes clearance problems, visibility issues, and expensive foundation rework. Procurement teams that skip the pole layout step often end up ordering twice: once for the wrong pole, once for the corrected one.
Start with three questions: Where is the signal head positioned relative to the approaching traffic? How many signal heads does the pole carry, and what is the total load? What is the available foundation depth and soil condition? The answers decide whether a vertical pole, a signal arm pole, or a double-arm pole is correct.
2. Vertical signal poles
A vertical pole beside the road can support signal heads and approved accessories without an overhead arm. It may be considered for pedestrian crossings, side-road approaches, school zones and parking entrances where the approved visibility and positioning requirements can be met. Compare the complete installed cost and confirm the pole, foundation and attachment design for the actual loads.
For a vertical pole, confirm the mounting height, quantity and weight of signal heads, and all accessory loads from the approved design. The foundation may be direct-embedded or flange-mounted where the structural and site requirements permit. Pedestrian push buttons or countdown displays require suitable mounting positions and attachments; confirm any mounting plates and holes before fabrication.
3. Signal arm poles
A signal arm pole carries a horizontal arm that extends over the approaching lane and suspends one or more signal heads directly above the driver line of sight. This is the most common pole for vehicle approaches on urban and suburban roads.
A signal arm pole positions signal heads over the required lane. Choose the mounting height and arm reach from the approved lane layout, clearances and visibility requirements. Supply the number, mass, dimensions and mounting positions of all heads for structural assessment. The pole, arm, base, anchors and foundation must be designed for the applicable loads and site conditions, including wind and vibration where relevant. Do not use a generic height, reach or head-load range in place of the project design.
4. Double-arm poles
A double-arm pole carries two horizontal arms at the same height, usually oriented in opposite directions. It is used at intersections where the same foundation can support signals for both approaches, instead of installing two separate signal arm poles.
For a double-arm pole, specify the mounting height, both arm lengths and all signal-head and accessory loads in the approved structural design. Size the foundation for the combined loads and site conditions, including any street-lighting arm. A shared pole can reduce the number of separate foundations and consolidate cable routes, but assess the complete civil works and structural requirements before selecting it for a retrofit.
5. Height, arm length and signal head load
Pole height and arm length affect signal position and clearance. Determine mounting height and lateral position from the approved road layout, required vehicle clearances, driver sight lines and structural design. Record the reference points used for each dimension; do not use a generic clearance range as the installation specification.
Set vertical and horizontal clearance, arm rise and head position from the approved road layout and the responsible authority’s requirements. Account for vehicle envelopes, pedestrians, roadside obstructions and maintenance access. Use the approved structural drawing for the support geometry rather than a generic clearance rule.
The supported assembly includes signal heads, mounting hardware, visors and any backplates. Assess dead loads and wind actions for the actual configuration and site design conditions. Select the pole, arm, connections and foundation from the approved structural calculations rather than a generic equivalent load for a signal diameter.
6. Foundation, anchor bolts and wind load
The foundation and anchors form part of the engineered support system. Check depth, dimensions, reinforcement, anchor arrangement and concrete requirements against the approved project drawings. Pole height or arm length alone cannot determine the foundation. Verify ground conditions and design loads before construction, and record inspection results before the foundation is concealed or loaded.
Soil and ground conditions affect foundation design, but soil type alone does not select the foundation or anchoring method. Give the responsible structural engineer the ground investigation, pole and arm geometry, equipment loads and applicable wind or seismic criteria. Confirm the approved foundation and inspection requirements before construction. A supplier’s example drawing is a design input, not approval for every site.
7. Material, finish and corrosion protection
Hot-dip galvanized steel and suitable aluminium alloys are possible materials for traffic-signal poles. Specify the material grade, structural design and applicable coating requirements for the project; ISO 1461 or ASTM A123 may be relevant to specified galvanized steel components. For corrosive sites, assess whether additional protective coatings are needed. Compare mass, strength, corrosion performance, maintenance and cost using the actual pole design rather than assuming that aluminium is restricted to small poles.
Select the corrosion-protection system using the site exposure, required maintenance plan and approved specification. Galvanizing, additional coating systems or an appropriate aluminium alloy may be considered, but no finish is universally suitable for all inland, urban or coastal sites. Coordinate fabrication and coating sequences. Any field cutting, drilling or coating repair must follow an approved method compatible with the pole and its protective system.
8. RFQ checklist for pole selection
Send the supplier the intersection layout with pole location, lane positions and approach directions; the signal head schedule (number, size, weight and mounting height per head); the wind zone (low, medium, high or design wind speed in m/s); the soil report or assumed soil class; the local standard (GB, AASHTO, EN, AS/NZS) and any authority-specific clauses; the finish requirement (galvanised, powder coat, paint system); and the foundation preference (direct-embed, flange-base, pre-cast). This lets the supplier return a quotation that includes pole, arm, base plate, anchor bolts, foundation drawing and finish in one package.
Frequently asked questions
What is the difference between a signal arm pole and a double-arm pole?
A signal arm pole can carry signal heads over an approach, while a double-arm arrangement may serve more than one approach from one foundation. Confirm the arm directions and head positions from the approved layout. The required load rating and foundation depend on the complete assembly, structural design and site conditions; do not assume that arm count alone determines foundation size.
How tall should a traffic light pole be?
Set mounting heights separately for vehicle and pedestrian applications using the approved layout and local requirements. Confirm the clearance beneath the signal head against the expected vehicle envelope, and check pedestrian visibility, accessibility, nearby obstructions and maintenance access. Record whether each height refers to the arm, the head or the overall pole.
How deep should the foundation be?
Foundation design depends on pole and arm geometry, equipment loads, wind and seismic requirements, and verified ground conditions. Direct-embed and flange-base arrangements need their own approved design. Do not select depth, concrete dimensions or anchor bolts from a generic pole-height example; obtain the project’s structural and geotechnical requirements before construction.
Do I need a structural engineer for the foundation?
For high-mount or double-arm poles, yes. The supplier foundation drawing is a starting point, but a structural engineer must verify the design for the local soil, wind zone and seismic category. This protects the authority and the public.
What finish should I specify for coastal sites?
Hot-dip galvanising to ISO 1461 plus an epoxy or polyurethane top coat is the typical specification for coastal or salt-air environments. Some authorities specify marine-grade aluminium instead. Both options significantly extend service life compared with galvanising only.
Can I attach a street light to the same pole?
Often yes. Many double-arm poles are designed with an additional short arm for a luminaire. Confirm the pole structural rating covers the combined load before adding lighting, and check the authority policy on shared signal-and-lighting poles.
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.
- Vertical signal polesVertical-pole applications: evaluate the approved height and mounting requirements
- Signal arm polesSignal-arm poles: determine height and arm length from the approved approach design
- Double-arm signal polesTwo-arm poles for 4-way intersections and corridor projects.
- LED traffic signal heads100mm, 200mm, 300mm and 400mm heads to mount on the pole.