A new form of public transport is operating at London Heathrow Airport, where individual driverless ‘pods’ have replaced shuttle buses serving the business car park at Terminal Five.
The Personal Rapid Transit system, which was developed by Ultra PRT and airport operator BAA, consists of 21 battery-powered air-conditioned vehicles each carrying up to four passengers and their luggage along a purpose-built 3.8km guideway between two car park ‘stations’ and the terminal building.
The pods are like taxis in that each individual or group travels in their own vehicle. At the stations, passengers use a touch screen to select their preferred language and then their destination. The control system immediately allocates a vehicle on the required path and timing for that journey and sends one to the station if none are waiting. When all passengers and luggage are on board the user presses a button to close the doors and another to begin travelling. During the journey, audio and on-screen information are delivered in the language selected at the beginning.
BAA expects the system to eliminate 50,000 bus journeys on the roads around Heathrow each year. A central computer ensures that pods are distributed at each station according to passenger demand. With waiting usually no more than 40 seconds and no congestion, typical journey time is ten minutes less than before, and more predictable. Over 100,000 passengers have used the pods since a trial service started on 18 April, and feedback has been overwhelmingly positive.
Ultra’s control system originated in a Bristol University research project into urban transport. It has been developed to route large numbers of individual vehicles between multiple points in a transport network, in real time. This multi-destination capability marks the system out from conventional people-movers.
Basildon-based ARKK worked closely with Ultra PRT in designing and developing the pods, and manufactured the 21 Heathrow vehicles. They are built using off-the-shelf components for reliability, with the same wheels as a Ford Ka and standard lead-acid batteries, which are recharged while the vehicles are waiting for passengers, using connections embedded in the guideway at the stations.
Fitted with 7kW electric motors, the pods can travel at up to 25mph (40km/h). Onboard laser sensors keep them on course between the raised kerbs of the guideway.
Arup designed the infrastructure for the 3.8km system, and also provided commercial management support to Ultra PRT and took on the role of design coordinator.
The team faced a number of challenges in designing the guideway. It had to cross over busy roads while staying below the level of the runway radar, and slope safely to the ground-level car park. Construction couldn't involve the closure or delay of any of the airport's other transport systems or critical supply lines.
Arup worked closely with all the stakeholders, including construction contractor Laing O’Rourke, to ensure that pods, guideway and computer systems all worked together seamlessly.
Because the pods are lightweight and only run when needed, they use less energy than the buses they replace. They are also cleaner and quieter.
"The Heathrow pod system offers a completely new form of public transport," says Max Vialou Clark, BAA Heathrow commercial director. "It will deliver a fast, efficient service for passengers and bring considerable environmental benefits, saving more than half of the fuel used by the public and private transport it replaces.”
Ultra PRT secured the Heathrow contract in 2005 – the company’s first commercial order after demonstrating a working prototype on its test track in Cardiff. Managing director Fraser Brown acknowledges that launching an operational service has taken much longer than originally forecast. “As well as dealing with ‘unknown unknowns’, what slowed us down was making sure we got it right,” he told E&T. “We redesigned the pod interior to make it more comfortable, and we spent a lot of time with the client to make the user interface as intuitive as possible. The feedback says it was time well spent.” Then the system had to undergo testing to satisfy the relevant approvals bodies before passenger trials could begin.
“This pilot at Heathrow proves we can make it work,” Brown continued. “Now we will try to market it around the world.”
Ultra is already partnering an Indian company, Fairwood, on a bid to build a PRT system in Amritsar for the Punjab Government, connecting the railway station and bus station with the Golden Temple – a major pilgrimage and tourist destination where internal combustion engine vehicles are banned.