Link network structures:
The way to consider queue lengths in a master/shared link combination (a ‘link-share’ as we like to call it nowadays), and indeed all the data in the final output table, is as a single link. Hence, if a queue is output as being 10 (and the same value will appear for the master and shared links) then the queue is 10 over the combined links: if the link represents one lane, the queue will be 10 per lane, if two lanes are modelled, the queue will be 5 per lane, etc. It is a key to using TRANSYT that the master link and shared link(s) are NOT used to model lanes separately. The reason for using master and shared links is to allow cyclic flow profiles to be kept separate – for roundabouts this is to keep OD movements intact.
In the TRANSYT 12 output ‘PRT’ file the queue associated with the shared link combination is repeated on each of the shared links. In the Network Construction Editor (NetCon) it was decided to display the queue just once and position it on the major link since there will only ever be one major link defined (for a shared link combination).
Additionally, In TRANSYT 13 and later, the repeated values associated with minor shared links are shown inside brackets to remind users that they are NOT to be added together to give a total queue length. – They ARE the total.
Traffic stream network structures:
The use of traffic streams have the same benefit of using link-shares, as they create, behind the scenes, a fully populated link structure – These ‘links’ are referred to in this context as ‘path segments’ as contiguous chances of these are used to establish ‘paths’ for traffic from each O-D origin to each O-D destination within a local O-D matrix. The use of traffic streams hide the complexity of the link structure. It also allows TRANSYT to have a one-to-one relationship between a real lane and a lane in the model, while retaining the benefits of the link structure, such as keeping CFPs separated so that flows of traffic are modelled accurately.