Details
A motorway is a linear operation, and that single geometric fact changes almost everything about how its communication is designed.
Corridor coverage
Ordinary radio planning covers an area. A motorway needs coverage along a band a few hundred metres wide and hundreds of kilometres long. A repeater sited for area coverage spends most of its energy on terrain nobody works in.
Corridor design instead uses:
- Linear siting along the alignment, with spacing set by terrain rather than by a uniform grid
- Directional antennas shaped along the road rather than radiating in all directions
- Existing structures — gantries, service buildings, toll plazas, tunnel portals — as antenna positions
- Simulcast where patrols must never change channel, or multi-site with roaming where they can
Simulcast earns its cost here more clearly than in most applications. A patrol vehicle at speed will not reliably change channel at each boundary, and the call that is missed will be the one about an incident.
Tunnels
Tunnels are the highest-consequence part of a motorway and the hardest to cover. Above defined lengths, emergency service communication inside is a statutory condition of operation.
The established answer is a leaky feeder running the bore, typically carrying operator radio, mobile operator bands and public-safety frequencies together on shared infrastructure. Design points that matter:
- Redundant feed from both portals, so a cable break degrades rather than halves coverage
- Fire-resistant cable specification and separated routes for critical paths
- Power with backup, sized for the incident rather than for normal operation
- Integration with the tunnel control system — ventilation, signage, barriers, cameras
- Verified measurement along the full length, as the handover document
Who is on the system
| Team | Requirement |
|---|---|
| Patrol vehicles | Corridor-wide coverage, immediate contact with control |
| Maintenance | Coverage at work sites including hard shoulder and structures |
| Tunnel operations | Coverage inside, link to control and to emergency services |
| Toll and service areas | Local coverage, security and incident handling |
| Winter operations | Coverage on the whole network, including in poor conditions |
| Control centre | All groups, position, recording, incident logging |
Incident command
An incident on a motorway involves the operator, traffic police, ambulance, fire service and often the gendarmerie, working in a hazardous live-traffic environment where minutes of lane closure carry a measurable cost.
The communication requirement is a common picture: who is on scene, what has been closed, what is inbound. That comes from a control-centre position with visibility of all groups, vehicle position, recording, and gateway arrangements with the other agencies agreed in advance.
Technology
DMR or DMR Tier III for the operator's own teams; TETRA where the operator must interoperate directly with public safety; PoC for sections beyond economical infrastructure and for management vehicles.
TechnoRF designs, licenses, installs, measures and maintains these systems, including tunnel installations and their periodic verification. Get in touch.
Frequently Asked Questions
Why is a motorway harder to cover than a city?
Because the geometry is wrong for ordinary radio planning. Coverage is needed along a narrow band hundreds of kilometres long, not over an area, so a repeater sited for area coverage wastes most of its footprint on empty terrain. Corridor coverage uses linear siting, directional antennas along the alignment, and site spacing set by terrain rather than by population.
Is radio coverage in tunnels a legal requirement?
For tunnels above defined lengths, yes — emergency services must be able to communicate inside, and it is a condition of the tunnel operating. The technical answer is a leaky feeder along the bore, usually carrying operator radio, mobile bands and public-safety frequencies together on one system, with redundant feed so a cable break degrades coverage rather than removing half of it.
How do teams stay connected across a whole corridor?
Either by multi-site coverage with roaming, or by simulcast so nobody ever changes channel. On a long corridor simulcast is often worth its synchronisation cost, because a patrol driving at speed will not reliably switch channel at each boundary, and the missed call will be during an incident. Where the corridor exceeds what infrastructure can economically cover, PoC fills the remainder.
Are body-worn cameras useful for road patrols?
Where interactions are disputed or an incident is later investigated, yes — and the local recording is the value rather than a live stream. Continuous streaming from every unit saturates any network. Record locally, stream on demand or on alarm, and set retention and access rules under KVKK before deployment rather than after.