City planners around the globe are increasingly touting the merits of public transit systems as a preferable transportation alternative to roadways and private automobiles in high-density urban environments.

With public transportation set to play a role of increasing prominence in resolving the congestion and pollution problems of the world’s major cities, it’s important to give full consideration the options at hand that could eventually emerge as the mainstream transit solutions of the future.

London's Heathrow Airport has already introduced compact, driverless vehicles that are capable of ferrying passengers to their intended destinations autonomously.

Its Ultra Light Transit (ULTra) system is comprised of 21 electric mini-vehicles operating along a 3.9-kilometre route that connects Terminal 5 of the airport to the business passenger car park situated to its north.

ULTra Pods

ULTra Pods

 Each of the driverless “pods” contains four seats and possesses a 500-kilogram payload capacity, as well as sufficient space to accommodate extra luggage, wheelchairs or even shopping carts.

The pods operate independently without the use of rails, instead employing guidance lasers to navigate their way between parallel concrete barriers. The vehicles are all battery-powered and recharge while parked, dispensing with the need for on-track electrification and permitting increased complexity of route design.

The stripped-down nature of the system dramatically reduces capital outlays compared to other personal rapid transit solutions. The complete ULTra system, including vehicles and stations, is estimated to cost between US$5 million to US$8 million per route kilometre.

In addition to reduced cost, another chief advantage of the system is its heightened efficiency and sustainability. ULTra has replaced as many as 50,000 bus journeys at Heathrow Airport, slashing carbon emissions associated with automobile usage.

Another innovative form of PRT currently under development is the SkyTran system, which employs an elevated maglev track to ferry passengers around at a significant height above the ground.

The system involves the construction of passive magnetic levitation tracks that are held at heights of between six and nine metres above the ground by means of metal utility poles or attachment to adjacent infrastructure.

Compact two-seat passenger carriages are suspended beneath the track, enabling them to glide through the air without affecting ground-level pedestrian or vehicle traffic.

SkyTran is far faster than ULTra, capable of achieving speeds of as high as 160 kilometres per hour. The system is also distinguished by its efficiency, with an estimated fuel economy of 1.2 litres per 100 kilometres while travelling at top speed.



Its developers expect that SkyTran would cost only $6,200,000 per kilometre to build – just a tenth the cost per distance of light rail projects.

A small-scale prototype of SkyTran is currently under development at the Israel Aerospace Industries campus, with plans to deploy a fully operational system in Tel Aviv before the end of the year.

While the innovative PRT systems like ULTra and SkyTran appear to be the stuff of imaginative science fiction, there exist other solutions to enhancing urban public transportation that do not involve the adoption of complex technological remedies.

Bus rapid transit (BRT) systems are one example of a simple and practical solution to urban public transportation that does not entail advanced or costly technology.

The system was first employed in Curitiba, Brazil in the mid-1970s, before rapidly spreading to other parts of Latin America on the back of its initial success.

Bus rapid transit (BRT) systems

Bus rapid transit (BRT) systems

BRT essentially involves the creation of bus systems that are capable of achieving the volume and speed of light rail or underground metro systems by means of alternative road designs and traffic arrangements.

Key measures include the creation of fully dedicated lanes that enable buses to bypass congested traffic, alignment in the centre of roads to avoid curb-side delays, bus priority at intersections, as well as off-board fare collection and customised stations with platforms that are level with bus floors in order to reduce boarding and departure delay.

A chief advantage of BRT is the lack of complex and expensive infrastructure compared to other public transit options for dense urban areas, requiring little more than the establishment of special lanes and the construction of slightly more elaborate bus stops.

This in turn translates into far lower capital expenditures for the establishment of the full system. According to a study by the United States Government Accountability Office, the average capital cost per mile for the creation of dedicated bus lanes is $13.5 million, as compared to $34.8 million for light rail.

  • The article on PRT is welcome – There are three market-ready PRT systems now, the article refers to only one of them. Two others are 2getthere (netherlands) and SkyCube (aka Vecus (S. Korea) More are being developed vigorously.