Since late 2018 a smart motorway has been under construction on the M4 between Reading and the outskirts of London. This section of the M4 has joined stretches of 13 other motorways as part of the UK’s roll-out of smart motorways.

Under this scheme, traffic management systems manage traffic flow and speed limits, and overhead signage governs the use of the inside lane or hard shoulder. Smart motorways were introduced in 2006 and seemed like a viable solution for managing ever-increasing traffic volumes through technology.

However, earlier this year, the Transport Secretary paused the roll-out to allow for more in-depth data analysis on the safety and efficiency of existing smart motorways.

What is a smart motorway?

There are three types of smart motorway currently in use:

Controlled motorway, where the hard shoulder is still available for use in an emergency and speed limits are variable and controlled via a regional traffic centre.

Dynamic hard shoulder, where vehicles can use the hard shoulder at peak times and speed limits and lane use is controlled by the regional control centre. Emergency breakdown areas are available at intervals on these stretches of motorway.

All lane running, where there is no hard shoulder. The regional traffic centres control speed limits, and there are emergency breakdown areas available, and lanes are marked as closed if a car breaks down in the inside lane.

The story so far

Since the introduction of smart motorways, there has been an increasing concern about the safety of using the hard shoulder as a driving lane. The government recently launched an enquiry into the rising number of fatalities on smart motorways. In 2016 the Transport Select Committee expressed “deep scepticism” about the design and implementation of all lane running motorways.

The government proposed several safety improvements. In November 2020, the Transport Select Committee followed up with another report asking for a pause in the roll-out of new all lane running smart motorway projects whilst safety data was reviewed. The government has agreed to do this.

The committee also recommended emergency refuge safety areas be a maximum of one mile apart and called for a review of improved stopped vehicle technology.  

Smart Motorways in the UK Since late 2018 a smart motorway has been under construction on the M4 between Reading and the outskirts of London. This section of the M4 has joined stretches of 13 other motorways as part of the UK's roll-out of smart motorways.

The benefits of smart motorways

The introduction of smart motorways in 2006 was primarily to tackle stop-start congestion through variable speed limits and the introduction, where possible, of an additional lane.

Broadly speaking, there has been an improvement in traffic flow. Additionally, the reduction in stop-start congestion has reduced emissions and kept traffic moving. There have also been cost savings in utilising the existing motorway footprint by converting the hard shoulder.

On-going concerns about safety

However, these benefits are challenged by safety concerns. If you break down on a smart motorway, you could be a considerable distance from an emergency breakdown area. If you are in a car with a child or older person, getting to safety may not be straightforward and may be downright scary, especially if, as was admitted by Highways England in 2016, it takes 17 minutes before you are noticed and warning signs appear on the overhead gantries.

The AA has stopped sending crews to smart motorway incidents. Dealing with a breakdown on the hard shoulder is scary enough in normal circumstances; imagine if that is on an all lane running stretch of smart motorway. Between 2014 and 2019, 38 people died either due to the lack of a hard shoulder or being on the hard shoulder when it was a live lane.

In addition to the safety issues, many drivers admit to being confused by the variable lanes and speed limits on smart motorways.

The future of smart motorways

The promise of smart motorways was one where technology would make road travel more dynamic and data-driven. In reality, safety concerns have made this promise more difficult to achieve than imagined. Whilst National Highways mulls over the data and looks at ways of using technology to ensure improved safety for broken down vehicles, the initial promise of smart motorways seems a long way off.

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