Multimodal’s latest blog post looks at how and when to model gradients in VISSIM.Read More
The latest in Multimodal’s series of technical posts changes focus slightly, this time concentrating on traffic data input and justifying its suitability for use in microsimulation modelling.Read More
Two recent projects which Multimodal have undertaken identified an issue with the traffic signal add-on – PC MOVA – being unable to accurately model hold messages within the external simulator (in this case, VISSIM).
A hold message requires a signal to be constantly sent, which cannot be set-up when configuring the PC MOVA connection file on its own.
As such Multimodal, in collaboration with Dan Preece at Integrated Traffic Services Ltd, have identified a workaround within PTV VISSIM.Read More
One of the most essential aspects of traffic modelling is the accurate distribution of traffic flows around a specified network. When working on dynamic assignment models, these flows are represented through origin-destination matrices (either through externally referenced .fma files, or through internal, embedded matrices).Read More
Carrying on Multimodal’s series of technical blogs for microsimulation modelling (see Dynamic Assignment, Speed Distributions and Turning Radii Speeds as previous posts), our next topic focuses on the modelling of flares and merges in urban areas.Read More
This post focuses on the need to consider appropriate reduced speed areas for turns and then their associated speeds when developing microsimulation models.
Transport for London’s (TfL) Modelling Guidelines suggest that speed distributions used for turns should be dependent on the turning radii (see figure below).Read More
When developing a microsimulation model, one of the early steps is to ensure that the desired speed distributions used in the model are appropriate for the area and network modelled.
At Multimodal, we have a template which bases these initial distributions on two key datasets – the Department for Transport’s (DfT) ‘vehicle speed compliance’ tables and Transport for London’s (TfL) speed profiles.Read More
At Multimodal, we keep an eye on the PTV VISSIM Forum on LinkedIN and recently, have noticed an increased number of posts in relation to dynamic assignment.
As such, we thought it would be worth jotting down our thoughts and current methodology and sharing it publicly. We are well aware that there is no ‘one solution’ to undertaking dynamic assignment and this is very much our own current methodology, but by sharing it to a wider audience, we hope this can help to generate further debate and/ or improvement and provide some help to those who are looking for a starting point with dynamic assignment.Read More