PERSONAL RAPID TRANSPORT

WHAT IS IT?
In cities and congested areas, Personal Rapid Transport, or PRT, is the transport of the future —think of it as a system of buses or individual train carriages that you can summon when needed. There's already a PRT system in place at London's Heathrow Terminal 5: Urban Light Transit (ULTra) is a fleet of 21 driverless electric vehicles which ferry passengers around silently, cheaply and a lot more quickly than buses or trains. Launched in May 2011, the Pods already carry some 500,000 passengers a year. So, JohnnyCabs are now a reality — although sadly minus the chirpy droid in the front seat.

ALL HAIL
Because people don't all arrive in the car park at once, a scheduled bus service creates delays, ULTra pods are instead called when needed, so there's a steady flow of passengers (and you don't have to stand in a car park for 10 minutes).

TYRE WHEN READY
Unlike other futuristic transport systems, for instance monorails, ULTra needs no track to be laid or tunnels to be dug; it runs on fairly standard tyres. With a simple road and a few guide rails all that's needed, installation is cheap and efficient.

GREEN FLASH
ULTra pods may only have a top speed of 40km/h, but that's still more than most Tube trains (average speed: 33km/h) and considerably faster than London traffic (average speed: 16km/h). All that and they produce no emissions themselves.

SEAT YOURSELF
Each pod sits up to six passengers, with room for bicycles and prams. They can also be adapted for freight, and will carry up to 500kg each. When their batteries become depleted, the pods automatically return to a charging point and re-juice themselves.

THE FUTURE OF PRT
Because it's expensive and disruptive to dig tunnels underneath a populated area, rapidly growing cities in Asia are looking to ULTra as an alternative to a metro. The Indian cities of Gurgaon and Delhi are already conducting trials, and they're unlikely to be the last.