LED Traffic Lights for Highway and Tunnel Applications

Design for the Approach

Drivers approaching a highway merge, tunnel portal or lane-control point need enough time to identify and act on the signal indication. Signal size, aspect layout, placement, mounting height and viewing angle should be considered together with the road geometry and operating speed.

Where lane control is required, make the indication system clear and consistent with the approved traffic-management plan.

Consider the Environment

Tunnels and high-speed roads can expose equipment to vibration, dust, moisture, exhaust residue, wind and significant temperature variation. Specify suitable housings, seals, cable entries and mounting components for the project environment.

Maintenance access is also a design issue. Equipment should be placed so that inspection and replacement can be performed under an approved traffic-control arrangement.

Integrate with the Control System

Signal heads, lane-control indications, controllers, detection equipment and communications must be coordinated. Document the required operating modes, fault behaviour and manual-control arrangements before procurement.

For complex projects, use factory checks and site commissioning procedures to confirm that field equipment responds correctly to the intended control logic.

Questions for Project Teams

• What decision distance and visibility conditions apply?
• Which lane-control or warning indications are required?
• What environmental and maintenance constraints apply?
• How will the equipment integrate with the control and communications system?