How does a single lane vehicle control system work?
Where opposing traffic shares one narrow lane, an alternating-flow control system manages when each direction may enter. The site geometry, detection method and operating procedures must be considered together.
Hold the opposing approach
Only compatible movements may be permitted into the shared section.
Confirm that the lane is clear
Detection, clearance timing and site procedures must account for vehicles still in the section.
Permit the next movement
The next direction receives permission only under the configured control conditions.
Detect demand and monitor the shared section
Detectors can register vehicle approach, entry or exit. Depending on the configuration, the controller may use these inputs to track occupancy. Missed detections, closely following vehicles and intermediate accesses must be considered.
Counting vehicles is not the same as independently proving that the lane is clear. Ask how the proposed system handles inconsistent counts and stopped vehicles.
Change direction only under the agreed clearance logic
The controller must apply the project’s clearance conditions before authorising the opposing direction. Travel distance, visibility, queues and possible stops in the shared section affect this assessment.
Do not treat simultaneous green indications at both ends as a general standby rule. Incompatible permissions must be prevented by the specified control logic.
Handle faults and manual intervention
Define the intended behaviour for detection faults, communication loss and power interruption. A reset alone does not prove that the shared lane is empty.
Manual operation and return to automatic control need documented procedures for authorised operators. Confirm these functions and their limits for the actual equipment configuration.
What to supply for a proposal
Send a plan showing lane length and width, gradients, blind spots, all accesses, pedestrian routes and any barriers. Add vehicle types, expected demand and available power.
Before operation, verify the detection, conflicting requests, clearance behaviour and fault handling against the project requirements. Keep the accepted settings and operating instructions for the site team.
Information to send with your enquiry
| Topic | Details to confirm |
|---|---|
| Geometry | Lane length, width, gradients and blind spots |
| Accesses | Entry, exit, intermediate accesses and pedestrians |
| Detection | Vehicle types, queues and occupancy assessment |
| Operation | Clearance conditions, fault handling and manual procedures |