This video shows the visualization an on-demand PRT system simulation done with VISSIM making use of the VISSIM COM interface.
(1) What is PRT?
PRT is short for "Personal Rapid Transit". It describes a public transport system with the charm and comfort of private traffic. The major differences and advantages of PRT compared to typical public transport systems are:
- Demand based trips, not based on schedules: Typically pods wait for passengers and not vice versa
- Direct, non-stop trip to destination (with no intermediate stops)
- Small driverless electric vehicles ("pods") holding up to 4-6 passengers hence no need to share trips with other people
- Higher station density as for typical urban transport, hence short ways to stations
- Quieter, faster (typically by factor 2 to 3) due to non-stop trips and more reliable due to dedicated guideway
- High energy efficiency due to light-weight vehicles and demand-only trips.
Among the real world PRT applications there are the systems at London Heathrow Airport (Terminal 5) and Masdar City (UAE). The latter one is introduced here: http://www.youtube.com/watch?v=PB_5TBZQNRY.
(2) VISSIM example
The VISSIM example shows a fictive scenario of a small PRT network including 4.7km of guideways, 7 stations, 1 depot and 40 pods (PRT vehicles). The pod 3D model was kindly provided to PTV by Advanced Transport Systems Ltd., Bristol, UK.
Pods travel on dedicated links (= guideway) without interference with other means of traffic. Branches and merges are possible inside this network to allow for stations and direction changes. However, junctions (crossings) at grade are not allowed in order to minimize accident probability. Wherever a junction would occur, the guideway is raised/lowered to pass the crossing guideway.
(3) Simulation behavior
The central control checks every 10 seconds for the first vehicle in the depot if there is a pod demand. If there is, the vehicle is released from the depot and directed to the station where it is needed.
Typically at every station there is at least 1 free pod available. For comfort, the default is set to 3 free pods per station. If another pod would arrive when already 3 free pods are in the station, then the first pod will leave the station without pax. For obvious reasons the amount of free pods at each station depends on the number of pods in the system. If there are too few pods and/or if there are demand peaks at a station then waiting times might occur for the pax.
Pods travel autonomously through the network and are controlled by a computer guidance system. In this example "intelligent" switches are used. This means, each switch knows the shortest path to each destination. This way a local re-routing (such as routing a free PRT vehicle to a station) is also possible.
An occupied pod travels non-stop from its starting station to the desired destination of the pax traveling in it. Free pods typically return to the depot (if there are enough free pods at the station where they finished their last trip). However, at every switch in the network they can be re-routed to another station. Due to this dynamic re-routing of free pods it can also happen that free pods that travel to a specific station actually are no longer needed when they arrive there. These pods can also be re-routed as all other free pods.
Due to the flexibility of the system and the relative small vehicles, PRT is particularly suited to handle disperse demand patterns with low to medium passenger volumes
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VISSIM Simulation: Two-Lane Hybrid Roundaboutby chrisburke23235,845 views
Nice. But i think the stations are poorly designed. Only one place to embark and disembark. People are waiting for pods, pods are also waiting for people.
ltintel 1 month ago
you see,where the hell is this,i have been to T5 4 times and never seen one/it
boeingnerd77 11 months ago