Autonomous bus trials in Cambridge

Thursday 5th March 2026

Regular readers may recall my write up of the autonomous bus trial in West Cambridge last summer as well as an abortive journey to travel on the second route introduced in south Cambridge just before Christmas when the bus was running in manual mode. It’s been a patient couple of months wait before making a return trip to Cambridge for another go at seeing this latest technology in action as it’s continued to prove temperamental but Whippet’s managing director, Ed Cameron kindly let me know things had now settled down so together with my friend Geoff Marshall, we paid another visit to Cambridge last Thursday to check out how this second route is doing.

It’s operated by one of three Alexander Dennis Enviro100EV buses which have been kitted out with clever software as well as a whole welter of censors, cameras and GPS technology to enable the buses to self drive in autonomous mode on public roads as has been seen in other trials in Sunderland, Milton Keynes, Edinburgh, Harwell and Didcot over the last few years.

The two trials in Cambridge are being overseen by the Greater Cambridge Partnership and go under a Connector branding with funding from the Centre for Connected and Autonomous Vehicles – a joint unit of the Department for Transport and Department for Business and Trade. Fusion Processing is masterminding the technology with Whippet providing the drivers as well as looking after the three buses which have been supplied by ADL. There’s also a Mellor bodied Fiat used on the West Cambridge trial which was used on the original trial in Didcot in 2023 operated by First Bus.

This latest Connector trial route runs between the Trumpington and Babraham Road Park & Ride sites in south Cambridge via the huge Cambridge Biomedial Campus site which includes Addenbrooke’s Hospital, the Royal Papworth Hospital, AstraZenica UK’s offices as well as many other medical, pharmaceutical and scientific businesses.

The route sees just four return journeys on Mondays to Fridays with an end to end journey time of around 20-23 minutes depending on direction.

One of four drivers who have received special training in how to handle an autonomous bus operates this on a rota as well as other standard bus driving work. But, of course, it’s a completely different driving approach needed with an autonomous bus. In essence it’s a ‘hands off’ approach but to always be ready at any time to take over the driving, either by hands going back on to the steering wheel or a foot touching the brake or accelerator. In such circumstances the autonomous mode immediately cuts out.

It’s quite remarkable to watch the bus drive itself along the route not only on major roads, but also through much of the complex Cambridge Biomedical Campus with its many pedestrian crossings and other potential hazards. However a short stretch of the most intricate part of the ‘twist and turn’ route through the Campus is not yet automated.

Geoff and I made a couple of round trips up and down the route to see the technology in action as well as meeting up with Ed Cameron to hear more about how this latest trial is going. On the first journey from Trumpington the technology wasn’t working but on reaching Babraham Road, our driver for the day, Sam, tried the usual trick of shutting the whole system down and booting it up again and luckily that did the business and after repositioning the bus at the Park & Ride terminal point so a connection could be made to the internet, Sam was confident we’d soon be in autonomous mode.

And, sure enough, she was right, for as she drove out of the site a buzzer sounded and the light came on above the bulkhead indicating to passengers on board the bus was now in autonomous mode.

We didn’t carry any passengers on that first round trip but on the 11:00 departure from Trumpington, Sam pulled up to the departure stand, also used by Stagecoach’s guided bus route A to the Cambridge Biomedical Campus (before continuing to the city centre and St Ives), where there was a queue of eight passengers waiting to get to Addenbrooke’s so they all came aboard, intrigued at the idea of travelling on a self-driving bus.

As we pulled away, Sam explained to everyone what was happening particularly as during the journey she warned there would be some instances of harsh braking where the software hasn’t quite got the measure of the road. I’d already noticed a couple of examples where road signs for roadworks were protruding out from the kerbside making the bus think it was a hazard. It also didn’t seem to like the hump before a zebra crossing on part of the route. Unlike other trials I’d travelled on, the bus wasn’t fitted with seatbelts but Sam did explain the nearside tip up seats weren’t to be used nor was standing permitted.

One particularly impressive aspect of the technology was it’s ability to correctly read the road and wait until a green filter light came on at a set of traffic lights where we turned right, setting off exactly as the filter came on.

It was also noticeable at roundabouts how the sensors accurately picked up traffic which was leaving at the exit from where we were joining, so could be ignored, but other traffic which was coming round in front of us to the next exit needed waiting for.

The sensors and cameras are an essential part of the technology and literally surround the bodywork of the bus to ensure every angle is covered.

Ed tells me the plan is for the Biomedical Campus route to be expanded to include two buses operating on it rather than one as well as adapting the third E100 bus to run on the West Cambridge route allowing the older Fiat bus to be stood down. This latter route has had its timetable expanded and now includes four lunch time journeys as well as five morning and six late afternoon journeys.

Ed also explained the Greater Cambridge Partnership has submitted a funding application for a further two years, which if successful will see one of the E100 buses upgraded from the current Level 3 (Conditional Driver Automation) to Level 4 (High Driving Automation) which means no driver is required as the bus is programmed to pull into the side if a problem arises. Alphabet’s Waymo subsidiary recently unveiled a Level 4 self driving taxi service in Arizona without a safety driver in the seat however under current UK legislation a driver (or “safety pilot”) has to be present. Notwithstanding this Waymo and Uber are set to launch driverless taxis in London later this year.

All this raises the question of what the future holds for autonomous vehicles. The technology is certainly impressive. Many aspects of it will undoubtedly improve safety and reduce risk since the software is designed with risk minimisation as an objective whereas humans need to make constant judgements depending on variable road conditions which can sometimes mean accidents, to say nothing of instances of buses losing their roofs driving under low bridges.

But, public transport is all about providing a service and a human presence is a crucial part of that. Even London’s “driverless” DLR has a member of staff on board for reassurance, and that uses fixed track. I can never see a time when a bus service on public roads (outside of defined and limited application such as airports and science park campuses etc) will operate without a person on board. So, when the Greater Cambridge Partnership suggests autonomous vehicles “could make public transport …. cost efficient” it implies that will be achieved through eliminating the need for a staff member on board, otherwise how is is going to save costs? I’m not sure how that sits with its other claim this has “the potential to improve passenger experience”.

And, frankly it’s just pie in the sky to think autonomous buses will therefore “help extend out-of-hours services, make rural routes more commercially viable ….. and improve accessibility for passengers with disabilities”. What?! Come again? How will it do that. In fact it’ll be the complete opposite for those with accessibility needs. A staff member is crucial.

I do hope we’re not seeing the beginning of another case where Ministers and civil servants with their hands on Government funding are being sold the idea by tech companies the future for buses is automation with no staff involvement thus pouring millions of pounds into developing the technology with that objective in mind. It’ll be DRT all over again except this time we’re talking mega millions.

Indeed this afternoon, Thursday, a meeting of the Greater Cambridge Partnership Executive Board will hear plans to extend the current trial until 2028 with a bid for a further £4 million funding from Government (and “over £1 million of industrial contributions”) which if successful would see expanded testing this summer including an aspiration to include the Cambridgeshire Busway in the trial.

Scepticism about future staffing issues aside, it’s impressive to see the technology in action. But, always with a ‘driver’ please.

Geoff’s video is now available on his YouTube channel and, as always, is worth a watch.

Roger French

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