Overview of Automated Road Vehicles
Automated Road Vehicles (ARVs), unlike conventional people movers, steer themselves along a flat surface without mechanical constraint. They have been used for decades in factories and warehouses to carry freight, where they are usually called Automated (or Automatic) Guided Vehicles. ARV systems differ from Automated Highways in that ARV vehicles are captive to the system, and are owned and operated as a single fleet. Recently, ARVs began carrying passengers in Europe and Japan.
The terminology for these vehicles can be confusing. Passenger ARVs are also referred to as "Road based people movers". What's more, passenger ARVs are sometimes called Automated Guided Vehicles after their factory counterparts. This site will only cover passenger vehicles and will always use the name Automated Road Vehicle.
ARVs serve some of the same markets as people movers, but cost far less. They generally operate at grade and carry their own energy supply, typically batteries. The "guideway" is just an ordinary road, except there are usually some kind of markers to help the vehicles determine their position. These are typically permanent magnets embedded in the roadway. Generally the road is reserved for ARVs, but some systems allow pedestrians and conventional cars to cross at certain points. The vehicles carry sensors such as scanning lasers to detect obstacles in their path and slow down and stop as necessary.
ARVs have become more popular in recent years because they allow the substitution of low cost electronics for mechanical complexity. The mechanical parts that are needed (the chassis) can be bought off the shelf. ARVs come in a variety of sizes from the 4-passenger ULTra to the 10-passenger ParkShuttle I and 20-passenger ParkShuttle II, up to the 50-passenger Toyota IMTS bus. Top speed is currently fairly low. ULTra runs at 25 mph (40 km/hr), the ParkShuttle II at 20 mph (32 km/hr), and the Toyota IMTS at 19 mph (30 km/hr). The ParkShuttle I, which is more or less obsolete, ran at about 15 mph (24 km/hr) when it began service in 1997 as the worlds first passenger carrying ARV to operate at a practical speed.
While ARV speeds are slow compared to other modes, this is not a major issue for short trips. For example, a 2 mile (3.2 km) trip at 25 mph (40 km/hr) takes only 4.8 minutes. Doubling the speed would not save much time.
The Toyota IMTS, the largest passenger ARV, is intended to offer a low cost alternative to light rail by running platoons of at least three driverless buses. Since this service would involve longer distances, the buses would run considerably faster than their current limit in public service of 19 mph (30 km/hr).
In addition to actual ARVs, this site discusses a proposed ARV design called the Automated Microbus, which is intended to minimize system costs.