Driverless buses, trackless trams: The future of public transport may already be here

Futurology is littered with predictions that failed to materialise, not least in the field of transport technology. In Edwardian times, when public transport was largely powered by horse or steam, a number of new concepts emerged which were hailed as the “future of public transport”.

In 1910, the Brennan Monorail was a gyroscopically stabilised, diesel-powered monorail train that ran on a circular test track at the White City in London. One of the early passengers on this 50-person prototype was then-home secretary Winston Churchill, who insisted on driving the train himself. The new technology reportedly “proved as interesting to the statesman as a new toy would to a child” – and Churchill is said to have told its Irish-Australian creator Louis Brennan: “Sir, your invention promises to revolutionise the railway systems of the world.”

Buoyed by such designs, engineering writers of the time looked forward to a future of us all whizzing around the country on new forms of hi-tech transport. But there were concerns too: in one popular 1912 encyclopaedia, an artist’s impression of a monorail train crossing a gorge via an unfeasibly skimpy bridge was accompanied by the warning:

When [note, not ‘if’] the monorail comes into general use, the feeling of insecurity – quite unnecessary but nevertheless inevitable – will be felt the strongest where there are single-rail bridges.

In fact, despite Churchill’s support, the Brennan Monorail never got further than the test track. In both its target markets – cheaply built branch lines and the military – a far simpler technology easily outdid it on grounds of practicality, flexibility and cost: the motorised bus and truck.

More than a century on, we are in a new era of transport technology disruption. In recent years, across the world, we have seen the emergence of the flying taxi and hyperloop train prototypes, hydrogen highways and trackless trams, as well as countless driverless car, taxi and bus pilots. At the same time, our most popular forms of public transport – the train and bus – are creaking under the strain of government funding cuts, union disputes and technological upheaval.

Is this the dawning of a much-needed revolution in mass transit, led by a new breed of clean-powered, demand-responsive, driverless vehicles? Or for all the people young and old, rural and urban-based, who rely on public transport for their everyday needs, will these grand designs turn out to be little more than modern versions of the Brennan Monorail flop?

Slow death of the bus?

A key factor influencing today’s public transport strategies is the commitment to limit planetary warming to 1.5℃ by reaching net zero emissions – a strategy the UK prime minister, Rishi Sunak, recently appeared to row back on. One global projection by the C40 network suggests public transport use in cities needs to double by 2030 to meet these targets.

But there are, of course, many other benefits of good public transport: from improving air quality and social inclusion to encouraging regional economic development (aka levelling up) and widening workforce participation.

In the UK, trains continue to hog the headlines, amid the rumoured cancellation of the northern section of the HS2 route, the general lack of rail investment in the north, ongoing industrial action over pay and staffing levels – and even the agonising 11-hour ordeal endured by rail passengers when their London to Edinburgh service was cancelled mid-route. Meanwhile, the long, slow collapse of the UK’s local bus services has gone largely unnoticed – other than by the people who have lost this critical mode of travel.

In March 2023, the House of Commons Transport Committee reported that England’s long-term decline in bus use outside London – a 15% drop between 2010-’11 and 2018-’19 – had deteriorated by a further 15% despite the government’s temporary £2 cap on fares (rising to £2.50 in November 2023). The situation is similar in Scotland, where bus use has declined 22% since 2007-’08.

In parallel with this decline, services and routes have been cut. Government bus grants have become increasingly selective, resulting in entire bus networks vanishing in a number of areas, and being left “hanging by a thread” in others.

This isn’t just in smaller towns and rural areas. Many larger settlements have also been affected, such as Stoke-on-Trent, where bus services have reduced by half since 2012-’14. In June 2023, when further cuts were announced, local media reported the impact on users such as this unhappy traveller:

I use the bus to get to work and back, and losing the service would mean reducing my hours. It’s getting us down. My husband’s an Avon rep, so he’s on and off the buses all the time. And the 8am bus I get is packed.

There are exceptions to this downward spiral. Manchester’s mayor, Andy Burnham, recently heralded the launch of the new, “re-regulated” Bee network of buses across Greater Manchester as “symbolic of a need to get more public control and ownership of critical services”. Praising this initiative, the Guardian wrote in its leader column:

The cutting of bus services on purely commercial grounds has led to greater social and economic isolation, restricting opportunities for the elderly and those without other means of getting around. Publicly regulated buses will at last allow greater accountability in relation to a service that, for many passengers, is fundamental to their daily quality of life.

But this is not the direction of travel in most parts of the country, where privatised, disconnected bus services remain dominant. A key structural reason for the decline in local bus use is that people’s patterns of travel have become much more dispersed and complex – behaviour that is hard to accommodate with a conventional, fixed-route public transport system such as the bus.

In fact, the strongest recent growth in local travel – seemingly exacerbated by the pandemic – has not been along major corridors to city centres, but in suburban and rural areas. Not only are people working in different ways but our economy is increasingly service and consumer-focused, and travel patterns have altered significantly as a result. The major areas of travel growth are now for social and leisure-related purposes – and again, traditional fixed-route bus services struggle to accommodate these types of trip, while it is so much easier to simply use a car.

The advent of certain digital technologies – in particular, cashless ticketing and journey planning apps – may make using public transport more desirable for those comfortable with such technology. But they don’t change the core service. A smart app is just a high-tech insult if buses don’t run when and where you want to go.

Emergence of trackless trams

In 2011, a small but radical new service was established to connect passengers using Heathrow Airport’s Terminal 5 with their parked cars. These Heathrow Pods consisted of driverless, four-seater vehicles available on demand, taking passengers straight to their destination along special elevated, segregated roadways. Users were promised they would “never have to wait more than 30 seconds for one to become available”.

While admittedly covering a very limited area, this radical alternative to the traditional fixed-route, scheduled model of public transport continues to garner praise since reopening after a hiatus during the pandemic. In the wake of the Heathrow Pods’ introduction, it had been expected that similar tracked, autonomous transport systems would develop elsewhere – but that hasn’t come about.

Rather, they could be seen as a small-vehicle precursor to the trackless tram systems that have subsequently emerged around the world. A combination of GPS and Lidar (light detection and ranging) guidance technologies are enabling battery-powered electric vehicles to fulfil the function of trams without the need for disruptive and costly track and overhead line infrastructure – making high-quality tram-style services viable beyond a handful of “global elite” cities.

The Chinese pioneered this form of public transport with the automated rapid transit vehicles, which first entered service in the eastern city of Zhuzhou in 2018, then rapidly spread to other Chinese cities. Initially manually driven, these trackless trams are now moving to autonomous operation. In Zhuzhou, a four-carriage model was introduced in 2021 which can carry 320 passengers at a maximum speed of just over 40mph, running on batteries charged at each station stop.

The concept is spreading beyond China: in 2022, a trial was announced for a five-mile route in the city of Stirling, Western Australia. In the UK, however, there is less inclination to depend on Chinese-controlled technology. And of course, trams – trackless or otherwise – don’t solve the issue of people wanting services that take them beyond a fixed route.

Meeting the modern, disparate mobility needs of an entire population doesn’t just require new types of vehicle or clever booking apps. We need a new vision of what public transport could be – and in different corners of the UK, there are places starting to offer this.

Self-driving public transport prototypes

Scotland’s CAVForth self-driving bus service, which came into public service in May 2023, is described on its website as “the world’s most ambitious and complex autonomous bus system”. Serving a 14-mile route that crosses the Forth Road Bridge on the outskirts of Edinburgh, the buses drive themselves along ordinary roads, obey traffic lights, and mix with pedestrians and cyclists. The main reaction of passengers seems to be that they are unaware the buses are not manually driven, as one early user wrote in CNet:

Though the bus is fully autonomous, you’d be forgiven for not really recognising it as such. You’ll find a regular steering wheel upfront, and behind it, a driver who’ll no doubt look as though they’re operating the vehicle as usual. UK law dictates that even fully autonomous vehicles must still have an ‘operator’ present who can take manual control, should the need arise.

Using a combination of three sets of Lidar technology and a “suite of cameras and radar”, the autonomous system can currently manage 90% of the route, according to ITPro, with the human driver “handling the exit from the depot and a few other locations”. The route is projected to expand further north, to the city of Dunfermline, in 2024.

Because the driver is a big part of bus running costs, if buses can eventually be autonomous then the challenging costs of providing late-night services or thinly used routes will be reduced – meaning that services could be improved. But the IT-led potential extends much further than a driverless bus.

In south-east England, Mi-Link – billed as “the UK’s first fully electric autonomous bus service” – is a move towards something more radical. As well as being electric-powered, this self-driving bus service – which launched in January 2023 and now runs on public roads to Didcot Parkway railway station in south Oxfordshire – is linked to a real-time journey planning app which helps travellers plan their journey whether they are walking, cycling or taking the bus to the Milton Park trading estate. It keeps users updated according to their individual travel preferences through the likes of WhatsApp and Messenger.

The integration of autonomous technology with a smart journey planning system feels critical if public transport is to prosper by attracting traditional car users. App-linked self-driving taxi fleets may well prove another key part of this future, and there are already entirely driverless public taxi fleets such as Waymo and Cruise in San Francisco, and the Robotaxi in China. On the whole, these appear to be technically successful, if highly subsidised and dependent on powerful 5G networks to operate. However, their emergence has been met with resistance both about perceived lack of safety and luddite-esque fears of potential job losses.

But for one of the best clues to what local public transport could look like in the future, we should again look closer to home, to a UK city that has long been renowned – and sometimes mocked – for its futuristic visions.

The future, according to Milton Keynes

After its foundation in 1967, the ambitious new town of Milton Keynes in Buckinghamshire soon began attracting an international reputation for anticipating future social, economic and cultural trends. Along the way, it was also derided as a city of roundabouts and concrete cows, with one architecture critic calling it “the doomed apotheosis of the fossil-fuel society”.

Today, its designers’ desire to accommodate extremely high levels of car use can be viewed as an environmentally irresponsible planning stance. But despite its detractors, Milton Keynes has proved extremely successful both economically and socially, and today has a growing reputation for being at the forefront of a more climate-friendly era of transport innovation.

Recently, its planners have grappled with the need for a new type of public transport – something that is “demand responsive” in the way of a taxi, but without taxi-level fares.

Demand-responsive transport services, or DRT, have been attempted by public authorities over the years – but largely without success. A global assessment in 2021 concluded that when a new demand-responsive transport service is set up, revenue from the low number of passengers could not cover the running costs, particularly those of the driver and back-office systems.

One early example was the Corlink DRT service in north Cornwall, which launched in 2002 to link rural communities with towns. The subsidy cost of over £28 per passenger trip was financially unsustainable and when special government support for the project ended, the service was withdrawn.

The Taxibus service to Bicester rail station, which launched around the same time, ran flexible routes off-peak and, by late 2003, was carrying 50,000 passengers a year. But even then, the service was eventually withdrawn as commercially unviable.

Twenty years on, however, Milton Keynes has addressed the cost problem, at least, with its DRT service, MK Connect. Facing the familiar situation of decreased funding to support the rising cost of uneconomic bus services, the city council opted not to implement cuts. Instead, it replaced its subsidised routes with a new demand-responsive service in partnership with the international tech company Via Transportation. Introduced in 2021, MK Connect still requires a subsidy, but half that of the conventional bus services it replaced.

The service is booked by users like an Uber taxi, logging their pick-up and drop-off addresses through a smartphone app, web portal or by phoning the contact centre. The app directs users to a nearby pick-up point, and they are dropped near their destination. Other passengers may be picked up and dropped off along the way.

The vehicles are small: as well as the fleet of eight-seater vans (many of which are electric), some cars are used. They generally arrive within 30 minutes of a booking being made, though the wait can be longer at busy times and in more rural areas. Fares are similar to that of traditional buses (payment is cashless), and the service covers the whole Milton Keynes city area – with far better coverage and operating times than the limited bus routes the service replaced.

An important feature is that the app will not allow someone to book on MK Connect if they could use a commercial bus route for their trip instead. In these cases, travellers are informed where to catch the conventional bus and when it will arrive. This ensures that MK Connect does not adversely affect existing viable bus routes, while improving the city’s public transport as a whole. Equally, if people cannot use existing buses due to a disability or other reason, they can register this and will always be accommodated on MK Connect.

The service is widely used, with some 40,000 trips being made each month (almost half a million each year) – a level of use that means its finances stack up. MK Connect has enabled trips to be made that previously were difficult or impossible using conventional buses, including for a man with sight loss who is the subject of a widely shared video.

One of us – Stephen – has used MK Connect on a number of occasions, and offers this mixed review of his experiences of the service:

I booked a trip to get to the barbers for a haircut. You can only book an hour or so beforehand, but I found a service that would get me there on time, which picked me up from the end of our road (the app guided me to the exact pick-up point). One other person joined us on the way and another was dropped off en route, but I got to my drop-off point in time for a three-minute walk across to the barbers. Coming back was less smooth, though. Initially, I was refused a booking – no vehicles were available. I waited a few minutes and tried again. This time I got a vehicle, after a 50-minute wait …

This mixed experience reflects the feedback that has been given in various passenger surveys. MK Connect is designed to serve modern, dispersed patterns of travel demands but is by no means perfect – some people find it harder to use than the buses it replaced, and there are problems with the vehicles being full at busy times, meaning prospective passengers are refused a booking or not accommodated for a long time. The booking system is also not yet reliable enough when a person has to get to an appointment or college lecture on time, say, or to connect with a specific train.

However, generally speaking, regular users appear to be getting used to the new system and its quirks. The real benefit to them, of course, is that this DRT service allows them to make trips that would be much more difficult, or impossible, using traditional route buses.

Another recently launched DRT, HertsLynx, aims to serve the rural fringes of Hertfordshire using four electric-powered, 16-seater minibuses in an operating zone centred around the market town of Buntingford and surrounding villages. Passengers are able to travel between 250 virtual bus stops, as well as nearby towns including Stevenage, Hitchin, Letchworth and Baldock – although travel to these towns is limited to fixed points (hospitals, train and bus stations, and high streets).

HertsLynx now makes 2,600 passenger trips a month and, like MK Connect, booking is by app, online or phone. With only four buses, it has hit a similar issue to MK Connect of being unable to take some trip requests when vehicles are fully in use, as noted in this recent review.

These two prototype services suggest a good model is emerging for local public transport, but that it needs refining. DRT services can best serve more dispersed trips, while conventional buses work well when a regular, predictable arrival time is needed and in situations of high demand. A good mix of the two is what is needed and Milton Keynes and HertsLynx, while heading that way, haven’t yet achieved it. Adding a in a Manchester-style regulation structure might well do that.

The future of local public transport

As the Brennan Monorail flop illustrated more than a century ago, predicting the future is a dangerous thing. But there is clearly potential to rethink public transport systems all over the world, in a way that makes a real difference to the planet and quality of daily life – by improving mobility while reducing costs, air pollution and congestion levels.

This revolution is being driven by a range of organisations, spanning powerful technology companies and IT startups as well as the existing public transport industry and both national and local policymakers. Central to a more diversified public transport future is easily accessed information and payment systems that allow users to customise different services for their own travel needs. Personalised apps on mobile devices to book and pay for public transport services will become increasingly important.

If you combine digital planning and payment systems, autonomous driving and a DRT service redesign, then a radically better form of public transport starts to emerge. Without the need for a driver, fixed-route buses could be smaller but run more frequently. Combined with DRT services to cover more dispersed trips, the potentially transformative, “small vehicle-small infrastructure” vision of public transport systems comes into place.

The result could be that, rather than people needing to adjust their behaviour to the schedules and routes of a bus or metro, they can travel directly, whenever they want, on services operating 24/7 – overcoming the poor quality of infrequent evening, night and Sunday public transport services experienced today.

All that said, the future may still not end up quite as automated as some technologists predict. Driverless vehicles overseen by control centres cost an awful lot to set up and run, and this may limit the use of driverless bus and taxi systems to where use is high enough to make the sums add up – in other words, major cities. For a good while yet, public transport vehicles in most medium-sized UK towns, as well as rural areas, are likely to remain manually driven.

Rather than trying to jump straight to an IT-driverless ideal, a phased introduction of upgradable, adaptable system designs makes more sense. In this way, the spectre of the Brennan Monorail should remain a useful reminder that not all technological advances will change our world for the better, and there is a real danger that second-best fixes could impede potentially transformative change. This is a journey that has only just started – and it’s going to be a bumpy ride.

Stephen Potter is Professor of Transport Strategy, The Open University. Matthew Cook is Professor of Innovation, The Open University. Miguel Valdez Lecturer in Technology and Innovation Management, The Open University.

This article was first published on The Conversation.