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Dynamic Traffic Assignment Model
CONTRAM
Continuous Traffic Assignment Model
www.contram.com
CONTRAM 8 (CONtinuous TRaffic Assignment Model) is a computer program for modelling traffic in road networks over time. Increasing congestion over longer time periods and larger areas, more complex travel behaviour and the introduction of Intelligent Transportation Systems (ITS), have placed ever increasing demands on traffic assignment models. CONTRAM 8 is ideally suited to addressing these demands through its three main functions:
- Calculating the build up and decay of queues and assigning traffic to minimum cost routes, reflecting the way drivers may behave when familiar with a network, to produce a full description of flows, delays and journey times in the network.
- Modelling unexpected situations such as incidents, and drivers' response to real-time information such as that provided by Variable Message Signs (VMS).
- Estimating the number of trips between different origin-destination pairs from traffic counts using a new weighted matrix estimation method.
Because it tracks the movements and interactions of vehicles in a physically realistic way, the dynamic assignment model at the heart of CONTRAM is capable of accurately representing time varying network conditions even when demand greatly exceeds network capacity. While it avoids the detail and computational cost of a microscopic vehicle simulation, where necessary it can model traffic almost down to the level of individual vehicles. Thus it can accommodate a wide range of journey purposes, behaviour, and responses to real-time information. CONTRAM is supplied as an integrated Windows graphical package. This contains all the features you would expect of Windows software. Key features include:
- Network diagram to scale, with background bitmap image facility
- On-screen network building and link shaping, and editing using templates
- Up to 32 user classes each with its own generalised costs
- Large number of time slices available enabling modelling from minute-to-minute detail up to full 24 hour periods at a chosen level of detail
- Extended traffic signal definitions including time-dependent plans, optimised and part-time signals and opposed turns
- Give-way junctions and roundabouts including flared approaches
- Speed/flow relationships on links, to represent buffer and motorway networks
- Banning of specified user classes from selected links and turning movements
- Provision for fixed route trips (eg buses) which interact fully with other traffic
- Variable link capacities and simulated tolls
- Simulation of capacity-reducing incidents and diversion routes
- Calculation of fuel consumption and emissions
Additional user-friendly features include:
- Select link analysis, origin-destination skim and detailed trip record available
- Text facility to provide roads and junctions with recognisable names
- Display of link values using variable bandwidths and multiple colours, or graphs
- Animated display running through time periods, or average over several periods
- Preload facility
- Batch running facility
In addition to its role in modelling traffic for appraisal purposes, CONTRAM's flexibility has led to it being chosen for many specialist projects. These include modelling of pedestrian movements in large spaces such as railway stations, studies of route guidance, research into the impact of travel time variability on route choice, and development of variable demand modelling to take into account how changes in trip cost affect the demand for travel. Within the MOLA system, which provides real-time advice to motorway operators in the event of an incident, CONTRAM is used to predict the effect of different diversion strategies. |
TRL and Mott MacDonald are committed to a long-term development program which will see continuing improvement in CONTRAM's capabilities.
If you would like further information on CONTRAM 8, (including purchasing, prices and workshops) and demonstration software see CONTRAM's own website at http://www.contram.com/.
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