Abstract

One of the first people mover systems in the Netherlands is the ParkShuttle system. The ParkShuttle is a low-capacity automatic navigating vehicle that operates without any physical guidance. It finds its own way automatically and travels on a simple ground-level asphalt track. This innovative form of passenger transport is ideally suited for short-distance feeder transport to public transport stations. Pilot projects were implemented at a long term car park (P3) at Amsterdam's Airport Schiphol and business park Rivium in the city of Capelle a/d IJssel (near Rotterdam). The ParkShuttle and the CyberCab are products of 2getthere, a subsidiary of Frog Navigation Systems.

2getthere is a subsidiary of Frog Navigation Systems. Frog Navigation Systems develops and markets (the controls for) Automated Guided Vehicles (AGVs). The FROG (Free Ranging On Grid) technology is applied in four distinctively different markets:

change-overs which involve long waiting times;

wide grid of PT-network, which causes long walking distances;

the routing (detours);

Also the low frequency of public transport provides the traveler with long waiting-times at a stop. The frequency cannot be increased because of the high labor cost of the drivers (in the Netherlands some 70% of total operating costs). Cost-effective operation of present day public transport modes often results in a low frequency.

The concept of automated transport combined with a network of closely spaced stops provides an excellent solution for moving people over short distances. The ParkShuttle pilot project was started both to provide a better service for existing and new transport markets by improving the quality of public transport and to produce environmental benefits in the densely populated area. The system uses autonomously operating vehicles that travel along a simple infrastructure using electronic navigation. Due to the simple infrastructure the cost-factor is low compared to other peoplemover systems. Generally people mover systems involve high investments because they require extensive infrastructure. See artist's sketch of an operating system.

The main characteristics of this new transportation system are:

Each vehicle has an on-board computer which stores an electronic map of the area in which the vehicle is required to operate. Using this map, the vehicle is able to plan its route to drive from point A to point B. The vehicle's starting position is known. As soon as the vehicle starts to move, it measures the distance traveled by means of encoders that count the number of wheel revolutions. At bends it is possible to calculate the vehicle's position from the angle of the wheels. This method may suffer from slight inaccuracies as a result of changes in vehicle load (full or empty) or an uneven or slippery road surface. For this reason, a number of calibration points are required at regular distances to check the calculated position and adjust it when necessary. These points are magnets embedded in the road surface. Each vehicle measures the location of magnets by means of a magnet ruler. Positioning accuracy of better than 3 cm is achieved, sufficient for the vehicle to come to a halt right next to the platform at a stop.

The vehicle is able to determine its own route because each vehicle has its own driving computer and positioning system. Regulation of route planning and the vehicle's interaction with other FROG vehicles and normal road traffic is taken care of by a supervisory computer control system called SuperFROG.

The ParkShuttle however has a safety system of sensitive and intelligent sensors. The sensors scan the area in front of the vehicle and will decelerate or stop the vehicle when an unknown obstacle is detected. An additional safety feature is provided by the bumper system that brings the vehicle to an immediate halt when it is impressed. In addition, the vehicle has emergency stop buttons (both inside and outside) that can be operated by the passengers. The speed is limited to 40 km/h obtain a good ride quality.

The vehicles are controlled by a supervisory computer system (SuperFROG) that sends the traffic control and request-messages to the vehicles via a radio data link. This is the only centrally-controlled function; the driving control takes place in the vehicle itself. This means there is no need for extensive radio communication with the central computer.

Traffic control with respect to other traffic (pedestrians, cyclists, cars and other public transport) is accomplished by means of traffic lights and/or barrier gates controlled by SuperFROG. SuperFROG activates the traffic lights and the barrier gates whenever a FROG vehicle approaches a crossing. SuperFROG will allow the vehicle to cross only after the traffic lights and/or barrier gates have reported back to confirm that they have been activated so that traffic control is reliable and fail-safe. Also, there is the in-vehicle obstacle detection system to prevent collisions.

The maximum load is 800 kg. The maximum vehicle weight is monitored by means of weight sensor. As soon as the total weight of the passengers and cargo exceeds the limit, the vehicle will refuse to depart and a message will automatically be announced. Sensors fitted in the doorways monitor the entrance and exit of passengers. The vehicle will never depart while a passenger is in the process of boarding and exiting.

The safety system consists of the obstacle detection system mentioned before. A camera and ommunications system are mounted in the vehicle. Both are in contact with the central control room. The camera allows constant monitoring of vehicle security and a rapid response to any irregularity. The communication system permits communication between the passengers and the control room, functioning as an intercom.

The SuperFROG supervisory computer system communicates via radio with the vehicles, the request-consoles and the traffic lights. SuperFROG receives the requests for the vehicles and decides which vehicle it will instruct to go to the station where the request was made. Vehicle instructions are managed efficiently and take into account the distances between the vehicles and stations and the status of the vehicles.

SuperFROG keeps a graphical record of the position of each vehicle. It also keeps record of the issued

instructions, the status of each vehicle, the status of the traffic zones and all relevant messages. Any malfunction is immediately reported to SuperFROG, which is linked to the central control room. The operator can continuously monitor the condition of the system. It is also very easy to change the lay-out of the routes so that routing can be altered, stations moved or added and the system expanded.

An overview map and a close-up map of the project geography is provided.

  The ParkShuttle connects Rivium to bus and subway station Kralingse Zoom – a 1300 meter journey over a single lane track with three passing locations. At Kralingse Zoom metro station direct access to the ParkShuttle track is prevented by a fence. Automatic platform doors give access to the ParkShuttle vehicle. The separation of the track gives extra safety and discourages people from walking on the track. The track is not fully separated. The only separation consists of a one meter high fence and a greenzone with bushes. Most applications of automated public transport systems will require a complete separation of the track, mostly for safety reasons.

Based on the success of the system, it was decided in December 2001 to upgrade the system from its’ pilot status. With the installation of six 2^nd-generation ParkShuttles the capacity will be tripled. At the same time the track will be extended. Operations are expected to resume in the summer of 2003. The extended Rivium application is a dual lane track, 2000 meters long with five stations. A highway is crossed by a specially constructed single lane bridge. Traffic management controls the access to the bridge and the flow of vehicles.

The ParkShuttle is operational from 6:45am to 6:45pm, Monday to Friday. During peak-hours all six ParkShuttles will be operational. In off-peak hours vehicles will be alternately charged, ensuring at least three vehicles are operational at all times.

  Long term parking lot P3 holds more than 10,000 parking spaces. The infrastructure of the ParkShuttles is a simple double loop track (see layout diagram). Each loop is one kilometer long and has 3 stops. Early 2002 an upgraded vehicle from the Rivium application was added. The five ParkShuttles transport passengers from stops near their cars to the passenger lounge. From there, buses provide transportation towards the departure terminals.

At any given time there are three ParkShuttles in operation. Meanwhile, the additional vehicles are being charged. The operational vehicles space themselves along the track to ensure minimal waiting times at each stop. When necessary the charging ParkShuttle can be made operational by manual override to provide extra capacity. The service is available 24/7 and is free of charge to users of the parking lot. Surveys prove that the system is well-used and greatly appreciated.

The ParkShuttles use audio signals to alert people at pedestrian crossings. Vehicle crossings are equipped with traffic lights and barriers.