Features of the Smart Motorway

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Technology is a key feature of a smart motorway. Being a smart driver is also an important feature to make sure all road users benefit.

Lane control signs

These are square electronic variable signs with three display options:

  • Variable speeds – changing the speed limit as conditions change is at the heart of a smart motorway. The speed limit displayed on the electronic speed sign is the legal speed limit. Smart motorways include automatic enforcement systems to further encourage drivers to keep to the posted speed limit.
  • Red X – when an incident occurs or work is being carried out on the road, the red X is displayed to close the lane. It is illegal and potentially very dangerous to drive under a red X.
  • Green arrow – directs drivers to change lanes.

Emergency stopping areas 

Because there is no shoulder on the northbound lanes, two emergency stopping areas will be built. Normal motorway rules apply; it is illegal to stop in an emergency stopping area for any other reason than an emergency. The stopping areas are fitted with sensors, CCTV cameras, and a phone which connects straight through to Wellington’s Transport Operations Centre (WTOC). Operators at the WTOC are alerted when a vehicle stops in the emergency stopping area and could send a road policing officer to check out the situation. Once a vehicle is ready to leave the emergency stopping area, WTOC operators can use the red X to close the lane allowing the vehicle time to get up to the speed of the main traffic flow.

Variable message signs 

These signs give drivers useful information so they can make informed decisions about their travel.

Being a smart driver

So all road users enjoy the benefits of a smart motorway, everyone has to contribute. It is easy to be a smart driver. All you need to do is:

  1. Keep to the posted speed limit (the posted limit is the legal limit) – the smart system calculates the optimum speed to minimise congestion and to get the maximum number of vehicles through the area. As well as breaking the law, exceeding the speed limit will put drivers to the back of the queue faster and just increase the size and duration of the queue.
  2. Minimise lane changes – changing lanes can have a shockwave effect on following vehicles. If everyone stays in the lane where possible, traffic moves smoothly and everyone arrives at their destination sooner.

Smart motorways are used in several other countries. You can find out about the introduction of smart motorways in Britain by the British Highways Agency.


Audio Māori keywords: 

Design a poster that encourages people to be a smart driver.

What is a Smart Motorway?

Benefits of a Smart Motorway


Lane control signs are square electronic signs with three display options. Image: NZTA.

Stopping areas will be fitted with sensors, cameras, and a phone which connects straight through to Wellington’s Transport Operations Centre (WTOC). Image: LEARNZ.

Variable message signs give drivers useful information so they can make decisions about their travel. Image: NZTA. 

Everyone has to do their bit so all road users can enjoy the benefits of a smart motorway. Image: NZTA.


I wonder if LED lights are

I wonder if LED lights are used in the electronic signs because they are cheap to run and last a long time. If not, I wonder why not?

What evidence is there that

What evidence is there that changing lanes slows down traffic? Have computer models showed this or have people analysed video footage or what?