Personal Rapid Transit Systems

Given that the bulk of the world's dwindling oil supplies are being consumed for transportation, if we ever are to prepare for the day when oil and its byproducts become prohibitively expensive, then we will need to drastically overhaul our methods of moving people and goods. Electric cars are often touted as the best realistic option, but that approach begs the question, how are we to obtain the electricity to recharge the cars' batteries every night? Much of the electricity generated in the United States is sourced from power plants that burn natural gas, which brings us right back to the problem of declining hydrocarbon resources — but the opposite side of the coin, namely, natural gas. Mass transit can greatly alleviate this problem, because it transports far more people and goods per unit of energy, versus individual cars and trucks. Unfortunately, urban sprawl in America — exacerbated by our mindless zoning laws — makes it nearly impossible for current mass transit systems to connect any desired two points in a city — especially since most Americans have become spoiled by individual cars, and will do anything to avoid walking a few blocks, to a mass transit station.

However, a workable compromise may be found in personal rapid transit (PRT) systems, each of which consists of a network of automated electric vehicles, often referred to as pods. The pods are basically self-service electric vehicles that run on guideways, using sensors in the ground or other vehicle location technologies. The exact specifications of each pod varies depending upon the manufacturer and the model, but essentially they are designed to hold four to six individuals. In a PRT system, each station has one or more pods waiting to be used. Anyone can get into a pod and, using a touch pad system, indicate where in the system they would like to go. Advocates of PRT systems argue that they combine the ecological benefits of mass transit with the convenience and privacy of small vehicles. There certainly are advantages to each pod not having its own engine — especially one burning hydrocarbon liquid fuel — and not involving the weight and cost of private navigation by the individual, and the consequent extensive safety requirements.

The concept of PRT systems originated in the 1950s, but has unfortunately seen little adoption worldwide. This is partly a result of the high setup costs, as well as the challenges of integrating a PRT system into the existing transportation networks of the typical modern city. (This points up the significant long-term costs of poor city planning, characteristic of most American metropolitan areas.) One of the earliest attempts at a PRT-like network is the Morgantown GRT (Group Rapid Transit) system, located in Morgantown, West Virginia. Opening for service in 1975, it currently connects the main university campus, located downtown, with two satellite campuses, as well as the city's central business district.

The concept of personal rapid transit should gain greater attention in the future, with the planned deployment of a new system at a major airport. Heathrow International Airport, the world's busiest international airport, is planning to implement in 2009 an extensive PRT system to transport passengers and their luggage around the huge airport. It will cut in half the amount of carbon emissions, compared to the previously used buses and trains. The plan is to start with at least 400 pods, connecting car parks, car rental centers, terminals, and even airport hotels.

We can only hope that other airports, and entire cities, will consider PRT systems as a transportation alternative in the future.