Further details and illustrations are available from the inventor, Lee Spreckler, upon request. He has applied for a patent. This concept is different from other active suspended PRT systems in that a method of lowring/raising the vehicle to reduce the number of expensive stations has been designed. For the details and drawings, contact leehsprecker@gmail.com


The ‘Ultimate PRT’ Proposal Overview

This proposal is for a ‘suspended’ Personal Rapid Transit system. This means that the passenger or freight carrying unit is ‘suspended’ below the track that carries the unit, which is called the ‘POD’.


My system will have PODs that will carry four passengers and two bicycles or two shopping carts or one wheelechair .

The Bogie and support system

The POD will be supported by two support columns. These columns will attach to a platform that will span between the two propulsion units or Bogies. The bogies will ride under the equipment platform and have a bearing system that allows each bogie to rotate independently from the platform and each other. This is like the trucks that support a rail car.

The track

The track or guideway for a suspended system is unlike the one for a supported system. The drive unit or bogie has its wheels very close together as opposed to the supported system where the wheels are out at the edge of the POD unit. Therefore the Suspended systems guideway will be far smaller than the one required for a Supported system

The Roundabout

To provide for point to point travel with no intermediate stops some way must be provided to allow traffic at intersections to move continuously. The answer is something that people in Europe are used to seeing and here in the USA some cities are trying. It has many names so I choose to use Roundabout for my name for it. It is also called a traffic circle, Go-Round and others.

. When a transport unit enters the roundabout it will turn to the right. Then it will either turn right again to change directions or turn left to remain on the roundabout. If it wants to continue in the original direction it will turn right at the second switch. If it wants to change directions ¾ around it will turn left at the second switch and turn right at the third right switch. In the unlikely case where it wants to reverse its original direction it will turn left at the third switch and right at the fourth right switch. If it wants the passengers to get dizzy it will just continue to turn left forever.

The ‘Stations

For my PRT system I feel that providing the fastest service is the goal. There are three general types of PRT station. One is called the ‘in-line’ station. Here the PODs come into the station ‘nose-to-tail’, which means they follow each other into and out of the station.

On the PRT system the stations are ‘off-line’ which means that the transport unit is switched off of the ‘main’ line and into a station that was selected by the passengers. All other transport units proceed past the station non-stop.

My ‘recommended’ station is the ‘in-out’ station. Here the transport unit comes into the station and is switched to the farthest open slot. It stops there and discharges any passengers and is available to load passengers. If there are passengers there they can then board the POD. The transport unit can then immediately be ready to enter the start up track and go to the main track under the control of the station computer. The unit does not have to wait for other units to get out of its way. This provides the most efficient movement of people and PODs

The POD lowering/raising system

I have a patent applied for proposal to solve the problem of providing a ‘station’ at almost every door in residential areas and the problem of removing passengers from ‘stranded PODs. By splitting the POD support columns and hooking a cable from the lower part of the support column to hoists located on the equipment platform of the transport unit you can lower the POD to the ground without the need for complex tracks or any type of station.

The lowering/raising system

The cables from the hoists can attach to this bottom support pin also or an additional pin can be provided. When the POD is to be lowered, the hoists lift the lower column about 1 inch so that the clamp arms can open, clear the support pin and the solenoid on each clamp arm can be activated. This solenoid will pull the clamp arms clear of the support pin. Next the hoists will lower the POD on the hoist cables to the ground. On the ground there will be four round and level cement pads for the feet of the POD to rest on. The hoists will have a device to determine the weight on the hoist cables. When the hoists detect that the load is removed they will turn off. The POD is now safely on the ground.

Details of the ‘Pole Clamp’ system.

Being as the POD will be lowered to the ground on cables there is the possibility that winds could blow the POD around. To insure that the POD is stable while being lowered and that it will come down on the cement pads, there is another patent applied for device that I have developed. I call it the Pole Clamp. When the transport unit stops at one of these ‘pole stations’ the first thing that happens is that this device is activated. It extends an arm with clamping arms that go around the pole where the unit has stopped. When this device has completed it operation it will have a grasp of the pole with arms that have wheels that rest on the pole. As the POD is being lowered this wheeled arm will ride down and up the pole insuring that the POD is held stable to the pole.

Details of the ‘Ramp’ system

When the doors open a patent applied for ramp unit will be lowered to help insure a safe exit and entry for passengers.

When the POD is ready to be lifted the ramp will be raised. There will be a device on the lifting unit to detect excessive weight on the ramp. If there is excessive weight on the ramp an automated announcement will indicate that the weight must be removed for the doors to close. When the ramp is raised and the doors closed the hoists will activate. As soon as the weight sensors detect the PODs weight, the computer will verify that the load does not exceed the safe amount. If the weight is too high the computer will lower the POD, open the doors and lower the ramp. An automated message will state that some weight must be removed. This sequence will also be used in elevated stations. This will insure that the transport units are not carrying excessive weight.

System operation

Let’s walk through a ‘typical’ trip on this ‘limited’ system. A mom and two children from a family with only one auto, needs to go shopping. They walk three blocks to a PRT station and up the stairs. The walk took about 10 minutes. At a computer terminal mom selects their destination at a shopping area. Mom scans her card to pay for the trip and the terminal prints out a ticket for her. Now mom and the children follow the instructions on overhead signs that direct them to the next available POD. The POD is waiting with the doors open and the ramp down. Everybody gets on and mom inserts the ticket into the slot on the terminal in the POD. When everybody is ready mom or one of the children presses the ‘GO’ button.

The ramp lifts up and the doors close. Silently the POD begins to move onto the ‘speed-up’ track and gains speed. Soon the POD joins the main track with other PODs. The children start playing with their game units and mom gets out her electronic pad to check her shopping list. The average speed on the system is 35 mph. Their destination is 5 miles away. In just under 9 minutes the POD is pulling into their selected destination. 15 seconds before arriving there was a tone and announcement that they were arriving at their destination so that they could gather together whatever they had with them and be ready to exit.

Commercial use

The small PODs cannot replace the large transport trucks but might replace the smaller trucks delivering goods from a local warehouse to local businesses. Most small businesses receive their stock in small batches, as they do not have space to keep a large stock. If a business had a ‘pole’ station installed behind the business and the warehouse had a station or a ‘pole’ station the warehouse could load the goods onto a pallet and into a freight POD, to be transported to the business. No truck is blocking the alley behind the business and less cost to deliver the goods. Less costly delivery when the business owner wants it, not when the truck can get there. Delivery early or late when things are slow to allow unloading stock.

It will even be possible to deliver goods to customers this way. Once the pole stations start showing up in residential neighborhoods the deliveries will be almost to their door. The customer could be notified when the shipment leaves the store so they will be looking for it at their pole station address. To insure secure delivery the delivery POD could have a coded entry lock. The store would tell the customer what the code is when the POD is ready to leave. That way only the customer will be able to open the POD and retrieve the product. This also insures the store that the product has been delivered correctly. The on-board CCTV cameras will have a record of who retrieved the product too.

POD details

The POD should be as light and strong as possible. This probably means an aluminum frame with a fiberglass or carbon fiber body. The outside should be smooth for easy cleaning and good flow through the air.

Being as the POD must allow a wheelchair to enter, turn around and exit the open floor space is dictated to do that. I feel that the POD should accommodate a bicycle so that sets the interior width.

Accommodating the bicycle, shopping cart or wheelchair

I have indicated that I feel that the POD should be equipped to carry two bicycles or two ‘special’ shopping carts or a wheelchair. There should be two slots in the floor for bicycle tires to fit into. On the backside wall there should be a clamping system that will ‘grab’ onto the front tire of a bicycle as it is pushed into the slot on the floor. This ‘grabber’ will insure that the bicycle remains upright, as the POD is moving. Pressing the ‘release’ button above the ‘grabber’ unit will release the bicycle. Also on the backside wall there will be two other ‘grabber’ units. There will be guide channels by those ‘grabber units. If a customer rents or purchases a specially built shopping cart it may be used on the POD system. When the cart is pushed onto the POD it will be guided into the two side guide bars and onto the ‘grabber’ units. The ‘grabber’ units will lock onto the cart to insure that it remains safe while the POD is moving. The same ‘release’ button is used to release the ‘grabbers’ from holding the cart.

A word about paying

Being as there are no ‘drivers’ on the POD system it is not possible to accept cash payments. All payments must be made with an encoded card. Schools can buy them for students and staff to go to and from school. Businesses might buy them for their employees to get to and from work. All others must have some form of credit or debit card.


How are the transport units controlled?

The ‘self-driving’ autos are demonstrating some of the devices that are required to make the POD system work. The transport unit will have a computer. This computer will control where the unit goes by controlling the switching solenoids. When the destination is entered into the computer then, with the help of the ‘system’ computer, it will determine the routes to take to reach the destination.



While I am sure that I have not thought of every ‘special’ situation and developed a solution, I do feel that most situations have been delt with. Having a test track will help to find problems and solutions. Having a ‘demonstration’ system with multiple stations and routes will identify additional problems that need to be solved.

Last modified: 04/21/2016                  HOME