Laser-guided pods at Heathrow Airport

ULTra, or Urban Light Transport, is a self-driving, electric-powered pod manufactured by ULTra PRT, and is being used in London's Heathrow airport to transport passengers to and from the business parking lots.

Watch the video below to see the pods in action at the airport.

The Personal Rapid Transit (PRT) pods provide a sustainable alternative mode of transport compared to conventional road and rail transit systems.

Named Heathrow pod, the computer-driven electric vehicles are small and lightweight, and run on specially designed guideways.

According to ULTra PRT, the advantages of using the pods in place of other modes of transport are its "zero on-site emissions", the fact that it uses "extremely low overall energy", is "virtually silent" and is an on-demand service with 24-hour availability.

"[The ULTra pod] offers a completely new form of public transport — one that will deliver a fast, efficient service to passengers and bring considerable environmental benefits, saving more than half of the fuel used by existing forms of public or private transport," said David Holdcroft, BAA ULTra Heathrow Terminal 5 project manager.

Heathrow Airport has a total of 21 pods in use (or 22, according to New York Times' blogger Jim Witkin) and two stations, which transport passengers from the N3 Business Car Park to Terminal 5.

The guideway between the N3 Business Car Park and Terminal 5 is approximately 1.9km, and takes the pod about five to six minutes to reach its destination.

The pods are 3.7 (length) by 1.7 (width) by 1.8 (height) metres in size, and weigh 850kg. The maximum speed that the pods can reach is 40 kilometres per hour.

There are two benches on-board the Heathrow pods, which can hold four to six passengers, with enough storage space for luggage, baby prams, wheelchairs, bicycles and other small carry items. The pods can carry a total weight of 450kg.

Air conditioning can be found on-board the vehicles to either heat or cool the compartment.

Passengers enter where they want to go in the touchscreen Destination Selection Panel. Since the pods are service on demand, passengers don't have to share a pod with strangers and can select their destination without any intermediary stops.

Pods are monitored by CCTV, and passengers can contact the control centre at any time should any concerns arise.

The Heathrow pods are virtually silent, as they require less power than other modes of transport, and hence a reduction in noise pollution.

During trials, ULTra PRT recorded noise levels of around 35dBA at a distance of 10 metres from the pods, which were running at six metres per second. At 10m/s the noise level rose to around 45dBA, which, when compared to cars (65dBA) running at the same distance, is still quiet, according to ULTra PRT.

According to an analysis by ULTra PRT, the pods generate zero emissions, with an average energy use of 0.55mJ (millijoule) per passenger kilometre. "The average system energy usage for conventional forms of transport is between 1.2 and 2.4mJ per passenger km," said ULTra PRT.

The pods are charged at station berths, and use 0.15kWh/vehicle at 40kph. According to the company, "the vehicles are designed to be upgradable to future energy-storage technologies such as hydrogen fuel cells, ultracapacitors, flywheels and different battery chemistries."

The pods have four pneumatic tyres, conventional shock-absorbing suspension and front-wheel steering. The vehicles are comprised of an aluminium frame chassis and floor.

The exterior uses lightweight ABS panels, which are fitted with single or double-sided electric doors.

The Heathrow pods use a laser sensor system that guides the vehicles on the guideways and in the stations. With constant wireless communication, the pods are always in contact with the control centre, and, according to ULTra PRT, they "can navigate fully autonomously if communications is disrupted".

Delhi is considering the use of ULTra pod cars as a form of public transportation. ULTra PRT is also working on designs and proposals in the US: San Jose Airport, Santa Cruz, Alameda Point, Cupertino: City of Apple and Mountain View to name just a few.