Hydrock's transportation team uses PTV Vissim - a state-of-the-art tool for transport planning and highway network analysis -to deliver microsimulation modelling for clients on a range of projects from the small-scale (e.g. a drive-thru takeaway) to large-scale highway networks. This enables us to save clients money by minimising the over-prediction of queuing and delay which can happen in older software, and to accurately model pedestrians, cyclists and other non-car users.
We use it to model the behaviour of individual vehicles through a network in real time and provide a 3D visualisation. Clients value the video-format output for public exhibitions, committee meetings and public inquiries as the results can be visually demonstrated in real or fast-forward time for non-technical reviewers, consultees and the general public.
Vissim realistically simulates and balances highway capacity and traffic demand and as such is useful for modelling the impact of developments across a large network, where background traffic may divert or choose new routes as a result of congestion. Vissim complements and expands upon our other transport modelling capabilities, for example, the Junctions9 and LinSig software modelling tools, which provide more detailed junction-specific analysis for assessing the transport impact of a proposed development.
We have used Junctions9 and LinSig to successfully support numerous planning applications and these are valid and appropriate tools for assessing the impacts of development sites. However, although they are industry standard tools accepted by highway officers, unlike Vissim they have a reduced capability to balance traffic demand across a large network, and nor do they provide a ‘non-technical’ video output. As such micosimulation modelling is highly effective where there are either difficult highway issues, a requirement to assess a large network, or ‘user-friendly’ video outputs are needed to help get a site through committee.
Hydrock's specialist microsimulation modelling team has successfully used VISSIM in a number of scenarios, including:
- Truro urban extension – A complete corridor model was undertaken for Cornwall Council to assess the impact of large scale mixed use development along the A390 in Truro.
- Mount Wise, Plymouth – Hydrock used microsimulation modelling to overcome a difficult highways objection. The modelling completely changed the council's view on the impact the scheme would have, resulting in planning consent.
- A KFC drive-through – Vissim was used to demonstrate the average dwell time of customers at the drive-through kiosk and the resultant queues that formed. This showed that the queues did not encroach upon the local highway (contrary to the view of the highway authority) and planning consent was granted in an otherwise ‘stalemate’ situation.
- Noss on Dart – A large mixed use scheme for a new marina. Vissim was used to prove that the existing access could accommodate the proposed traffic generation in addition to the existing ferry services.
- Minack Theatre, Porthcurno – Vissim was used to demonstrate the positive effect that could be achieved on traffic flow once drivers could see one another following the removal of vegetation on the key route to the Minack Theatre.
- Coyte Farm, St Austell – A detailed corridor study is currently being undertaken to demonstrate the impact of our client's site on the A390 and local junctions.
Vissim and other microsimulation packages are the network/strategic modelling software of choice for Highways England and Transport for West Midlands, as well as a large number of local authorities.
Key benefits of Vissim are:
- Representing real-life re-routing of traffic through networks
- Avoiding over-prediction of queues and delays at congested junctions
- Easy-to-understand representation for non-technical audiences
- Modelling the interaction of all modes
- Fine tuning of traffic signals/representation of intelligent transportation systems
- Public transport simulation (all modes)
- Pedestrian simulation.