Potholes can be small or large, shallow or deep, an inconvenience and also very dangerous. We have become accustomed to seeing them on the roads in the UK especially during the winter months, almost to the point where mistakenly driving over a pothole or swerving to avoid one is commonplace. The issue of potholes has ravaged the UK’s roads for a while now, and it’s something that is gradually getting worse and worse as time goes by. 

The Pothole Problem

‘You’re around about one and a half times more likely to break down as a result of hitting a pothole today than you were back in 2007’ – these are the words of Rod Dennis who is a spokesperson for RAC Breakdown. RAC’s members regularly report issues with their vehicles breaking down, with the main reasons for this being linked to incidents with potholes. To help analyse this trend, they have put together a measurement of data entitled the ‘RAC pothole index’. It is data that shows us how likely members of the RAC are to break down as a result of something that’s a problem on the road, whether it be a pothole or another road defect. 

‘So we use this basically to get some sense as to what the scale of the problem is. And also the issues that these actually cause the drivers because we do know that potholes regularly rank as one of the kind of the top bug bares for drivers in the UK according to our research’, says Rod.

According to Rod, the harm that this bug bare causes can vary. Any damage to a vehicle as a result of a pothole is always an inconvenience, but examples of damage that are able to be fixed by a RAC patrol team include punctures and the swapping of a tire if need be.

Alternatively, potholes can also cause serious damage to a vehicle. Depending on the angle that you hit the pothole and how high or low your vehicle rides on the road, the consequences can be disastrous. These include distorted tires, broken suspension springs – problems that would need to be fixed in a garage which would cost the driver a considerable amount of money. Plus, even if you are on two wheels as opposed to inside four, it can have more disastrous results. Whether you’re a cyclist, motorcyclist, or you use a scooter, potholes can be far more dangerous to not just your financial well-being, but also your own safety.

Papering Over The Cracks

A typical repair of a pothole can take around 10 to 15 minutes according to Mike Harper, Chief Executive of the Road Surface Treatments Association (RSTA). This duration of time seems extremely efficient, however this is a problem within itself. With more care and attention aimed at the repair, the UK’s roads could therefore diminish the regularity of potholes forming. 

According to Mike, the more sustainable method of fixing potholes involves sealing the edges and then compacting sustainable material into the hole. He estimates that this takes around a couple of hours to complete, but this repair has the potential to last up to 10 years.

‘It’s very expensive to do reactive maintenance and also long term it’s disruptive for the road users. So it might give us an idea that the council has reacted quickly and filled up individual hole, but in reality they’ll be back there in two weeks’ time to do it again, says Mike. And then again in three months time for example. So it’s really much better to take a little bit of time at the start and do it correctly and just do it once’.

‘So budgets are under pressure. And it’s a little bit like if you’re protecting wood on the outside of your house, for example, if you’ve got wooden window frames or something, you know, if you protect them regularly, you paint them a varnish them that they’ll last a long time, says Mike. You also know if you don’t do it, you can get away with it for a short amount of time, but it will catch you up and then you’ll have to replace the windows. And that’s exactly what’s happening in asphalt road surfaces in the UK’

The Robots Are Here…

During the classical period in ancient Greece, the Athenian philosopher Plato would state that the ideal city must flow smoothly and in harmony much like a living organism. 

‘So we’ve got our columns and beams and rows, which are sort of like the bones. And then we’ve got the various pipes which are like the blood vessels, says Professor Phil Purnell, professor of materials and structures at the School of Civil Engineering in Leeds University. ‘Then in later years, we’ve convinced ourselves that we built smart cities by having layers and layers of electronic monitoring, and sensing equipment, which is sort of like our nerves and the brains’.

However for Phil, the one factor that the city has always missed in this analogy with an organism is for the city being able to heal itself i.e. no white blood cells or inflammatory responses etc. It’s this correlation, plus an event that occurred in Manchester that provided to be the main catalyst for an exciting project. Back in August 2015, commuters were left shocked as a large sinkhole formed on Mancunian Way – a two-mile long motorway which operates as one of the main inroads to Manchester. The crater measured approximately 40ft and left the road closed for weeks causing major diversions for drivers.

‘If you dig down into why that sinkhole appeared, it will have been a millimetre scale defect in a pipe which water leaks out, says Phil. It erodes the supporting material beneath the pipe, the pipe sags, it cracks, more water comes out, it gets bigger and bigger yada yada yada = 10 metre hole.’

This event propelled a conversation amongst Phil and his colleagues at Leeds University. 

The Engineering and Physical Science Research Council (or EPSRC) ’Grand Challenge’ set out a project that primarily aimed to balance the impact of city infrastructure engineering on natural systems by using robots. This had three objectives; to develop technologies for autonomous defect detection and make them diagnosis compatible with new and existing infrastructure, secondly to understand and manage the interactions between our ecological environment, technology and our society and thirdly to develop robotic platforms to autonomously undertake minimally invasive infrastructure tasks in complex city environments. This is where the concept of drones and robots identifying and fixing potholes would come into play.

Prevention Is Better Than The Cure

At the heart of this project, the term ‘prevention is better than the cure’ is the motto that Phil and his colleagues are aiming to hammer home. In other words, these drones will aim to nip any minute crack in a road before they form into a pothole of a size that could do harm to your vehicle or yourself.

The team at Leeds University are tackling this from two separate levels. In relation to the drones, they aren’t trying to invent these and their materials from scratch. These drones will look like a standard commercial model that is able to habituate a 3d printer. In contrast, there are robots based upon the characteristics of a nematode worm and robots that are made up of a raspberry pi chip, a plastic motor and two infra-red sensors – similar to what you would find in a TV remote control. 

As well as ‘prevention is better than the cure’ being one of the key adages behind this ‘Grand Challenge’, the notion of autonomy is key. What Phil and the team are trying to do is programming the drones to make their own decisions.  

‘So the ethos of the project is that we’re not actually controlling the drones, we’re building the sensing control systems so they’re effectively autonomous to a large degree apart from the initial deployment and the collection’, says Phil. ‘Once it’s in the air, it’s making its own decision. It’s deciding where it goes, where it might take cues from the ground i.e. ‘there’s a road here’, ‘there’s not a road here’, ‘there’s another robot there’, ‘I need to communicate with that robot’. So it’s actually deciding where it goes.

With autonomy in mind, there are three stages in which a pothole operation is performed. The first step involves the identification of the crack, which is pinpointed by either the drone or one of the nematode robots. Then there’s identification of the defect. ‘It will basically scan the defect and it will say, right, what size is this defect? What shape is this defect?’ says Phil. ‘In an ideal world, it will also say, what’s the properties of the material around that defect? Because if you ever look at a traditional pothole repair, what tends to happen is you repair the pothole. And it all breaks up around the edge, because what you’ve put in the pothole is a lot stiffer or a lot less stiff than the road around the pothole…’

And the other characteristic that the drone will carry out is analysing the properties of the material that needs to be filled. This is where either the robot or the drone will talk to the 3d printer to make custom made repairs – repairs that are tailored for the specific material of the road that needs fixing. 

Moving Forward

‘I think I’m right in saying that the worm inspired robots have already had to go on a live road I think, we’re also got Highways England as a partner on the project’, states Phil. So somebody from Highways England chairs our steering committee at the moment. And so we’re also in talks with Highways England as to how we could actually deploy this on a trunk road or a major motorway at the moment. So that’s the kind of stage of deployment we’re at at the moment…’

This project of Phil’s is still in it’s early stages of it’s lifespan, but with Highways England onboard, there is promise. Some of the other drone systems that Phil and the team are using run into the realms of the 10s of thousands of pounds, with one of the designs, which Phil likens to a robot dog with it’s long carbon fibre robotic arms, reaching to the dizzy financial heights of around £100 to £200,000.

These numbers do seem quite high, however at the heart of this, the term ‘prevention is better than the cure’ is the message that Phil and his colleagues are trying to get across, and it’s one message that should be taken into account greatly with regards to the pothole pandemic…