PRTProject.com - The future of transportation

Design

Control

The vehicles are controlled on two distinct levels: an onboard vehicle control system (VCS) handles local functions (opening doors, user safety, etc) and a central control system (CCS) monitors and routes the fleet according to the needs of the system.

VCS (Vehicle Control System)

The VCS is in constant communication with the central control system.  The VCS utilizes onboard video cameras and motion sensors to monitor activity both outside and inside the vehicle.  Outside sensors allow the vehicle to track and avoid obstacles such as children, animals, or other vehicles.  Inside systems allow the vehicle to detect when passengers are safely seated, and so forth.  The VCS interacts with passengers via voice recognition to interpret commands ("stop here", "take me to school", etc).  Each passenger has a profile in the system such that "school" has a specific meaning depending on the user.  A touch screen is also provided as an additional way of communicating with the system, displaying route maps, event times, etc.

CCS (Central Control System)

The vehicle communicates with the central control system (CCS) to receive routing instructions and communicate various events across the system (a dog on the tracks, etc).  As a safety precaution, either system (VCS or CCS) can bring the vehicle to a stop.  Likewise both systems must approve of all vehicle movement.  The result is that, even if the CCS sends faulty instructions, the vehicle will still have sufficient onboard intelligence to detect and prevent a collision.  Alternatively, if a vehicle is malfunctioning, the CCS will detect the behavior through GPS tracking and initiate a shutdown of the vehicle, if necessary by triggered by stop points on the tracks (described later).  This redundancy of control insures the safety of the entire system.

While control is shared between the VCS and CCS, the passenger always has the final word due to safety reasons.  The passenger can always stop the vehicle at the next sidetrack or immediately in the event of an emergency.
 

Propulsion

PRT vehicles are powered by a 3rd electrified rail, running a non-lethal 48V.  A battery in included in the design, but only for running the non-propulsion systems (computer, door, etc).

The vehicles do not have a designated front or back, but instead travel equally well in either direction.
 

While conventional trains and lightrail systems rely solely on gravity to keep vehicles on the track, the PRT vehicle is considerably lighter and may require an additional set of guide wheels for safety purposes, similar to that employed on roller coasters.  The guide wheels are mounted such that they connect with the inner side of the rails.  Those displayed in this image are probably more extensive than what would be needed for PRT vehicles.

Vehicle Specialization

PRT vehicles are a shared public resource, available on demand, rather than individually owned.  While the majority of the vehicles will be dedicated to basic passenger service, the system also provides for specialized vehicles...

If an individual were to make a large purchase at the local hardware store, they would summon a public freight vehicle.  This fulfills the need of individuals who currently own pickup trucks for occasional weekend home improvement projects in a much more economical way.

Vehicles can be leased to businesses for a variety of customizations, although modification of underlying chassis or mechanics would not be allowed.  Vehicles in this category would not receive preferential routing.

Vehicles will also be customized for government functions such as emergency services - police, fire, and ambulances.  Vehicles of this sort would receive priority routing and include manual control overrides for dealing with emergency situations. As with conventional rail systems, the PRT system itself will also require specialized vehicles to handle track repair and inspections, clear debris from the rails, and so forth.

There could also be specialization within passenger vehicles, possibly a one-person vehicle since most travel consists of a single passenger.

Track Design

Traditional rail systems run parallel to the roadways, requiring vast infrastructure investments due to raised platforms, tunnels, and land acquisitions.  Lightrail systems can cost as much as $70 million per mile and take years to implement even short distances.

The PRT rails are instead mounted atop the existing road surfaces, greatly reducing the construction costs and implementation times.

The tracks are supported at periodically spaced columns mounted into the ground.  The intersection of the columns and the track would be designed to allow adjustments to compensate for ground settling, keeping the tracks extremely level.  The tracks could also be detached from the columns during street maintenance (underground utility work, etc) very easily.  The paved surface below the rails would now last much longer since it would not be experiencing traffic, a significant cost savings.

The PRT uses "in-vehicle" switching.  This means the vehicles control the switching operation, providing the mechanical energy necessary to throw the switch, thus simplifying the switches themselves.  It will be important to keep the cost of the switches low given the large number required.  In trains, faulty or incorrectly set switches are often the cause of accidents.  To address this concern, the central routing system will assume that the vehicle is still on the main line until (1) the vehicle reports the exit as successful and (2) a sensor in the sidetrack confirms the vehicle is on the siding.

The design criteria for passenger loading / unloading requires that no single vehicle blocks another.  So if you're neighbor is busy loading luggage into a vehicle, you would not be late for work.  So the only delay would be it time it takes the vehicle to arrive.  But if the central routing system detects a pattern, say you leave for work every weekday morning at 7:00am, it will proactively start sending a vehicle to your area in anticipation of your call.

residential track layout

At locations involving high volume loading / unloading, such as the local mall, people would line up for the next available vehicle (a "bank line").  The location would have several sidings, depending on volume.

 

customers queuing up for vehicles

At key points on the main track, stop points will be implemented, controlled by the central routing system.  If a stop point is activated, any passing vehicle is disabled (stopped) when it makes contact.  This is a safety precaution in the event of a runaway vehicle.

 

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