Coordinated ramp signals

Coordinated ramp signals meter traffic onto Melbourne motorways in a measured way to minimise congestion

What are ramp signals?

Coordinated ramp signals meter traffic onto Melbourne motorways in a measured way. 

  • The system is based on the latest traffic flow science to provide stable and reliable travel that optimises traffic throughput and travel speed along the whole motorway (not just at ramp merges). 
  • Coordinated ramp signals also help to prevent, or delay, traffic flow breakdown and congestion.  

A well-managed motorway has safe and productive spacing between vehicles and may look emptier than expected. If traffic is kept moving, there is more throughput per hour, helping to avoid a congested motorway where vehicles travel slowly and bunch up close together.

When traffic from one motorway merges with another, it can get really congested. Find out how Melbourne’s motorway to motorway ramp signals help keep traffic flowing.

What motorists need to know

Road rules

Motorway ramp signals are traffic lights, as defined in Road Safety Road Rules.  

Rule No. 56 defines a driver’s responsibilities at a red or yellow traffic light.  

Warning and advisory Signs

When ramp signals are operating, warning signs are activated at the start of the motorway ramp.

image showing ramp on signal sign

On some ramps other signs may also provide a warning message that motorists need to prepare to stop.  

  • On entry ramps from one motorway to another, variable speed limit signs are used to manage traffic speeds
image showing prepare to stop sign

At most interchanges, other information signs provide traffic conditions and travel time on the motorway. 

  • These signs are also used to provide other information such as warning of an incident.
image showing warning advisory sign displaying incidents and drive time to exits

Switching the signals on and off

  1. The sequence for switching ramp signals on includes flashing the yellow light and activating the warning signs.  
  2. The signals then change to red before showing green to commence the traffic metering. The signals have a variable cycle time which is adjusted automatically in real-time according to the traffic conditions.  
  3. When the ramp signals are switching off, the yellow light flashes briefly before the signals and warning signs are switched off.

How do ramp signals work?

Principles for minimising congestion

Ramp metering signals maintain traffic stability and traffic flow within Melbourne’s motorways. 

  • When ramp metering signals switch on it may be due to a traffic problem at the merge or as part of a system response to manage traffic at another point along the motorway.  
  • The ramp metering signals are automated to only operate when needed, switching off when metering is no longer required.  
  • The system uses a dynamic suite of algorithms that make combined decisions, aiming to balance ramp queues and wait times in order to give all road users a fair go. 

Benefits of coordinated ramp signals

Motorway benefits

There are a number of benefits that result from coordinated ramp metering signals. These include: 

  • improved road safety, due to safer management of merging traffic and more stable motorway travel with less stop-start conditions
  • a more reliable service
  • reduced overall trip times due to improved travel speed
  • minimisation of flow breakdown and congestion
  • increased motorway throughput.

Arterial road benefits

  • Managed motorways with coordinated ramp metering help to achieve higher sustainable motorway flows, showing benefits for the broader arterial road network. 
  • If a motorway can carry more traffic in the peak periods, the operation of arterial roads (non-motorway roads) will also be more efficient.  

More information

Coordinated ramp signal FAQs 

Principal aims of coordinated ramp signals

Studies of coordinated ramp signals

Further detailed reading is also available in the various Traffic engineering manuals