Software Development

Peter Davidson Consultancy’s (PDC) specialist team of software engineers, with its proven track record of successful software product development, undertake software consultancy for clients, including information technology systems, Geographic Information Systems, the web and other software solutions. They use various design methodologies for system analysis and design including Object Orientated Analysis Design. Our software capability stems from our work in the transportation field, where we have a sound track record for providing innovative software solutions. Our team has the capability to adopt state-of-the-art techniques and also have the experience to use them and when not to use them.

Here are some brief details about some projects we have conducted in this area.

Visual Transport Modeller (Visual-tm)

Date: 1988 to Present

Our Visual-tm software is an integrated modelling workbench for the transport planner for:

  • Create really exciting transport solutions – solutions that are more sustainable and can move dependence away from the car, for some types of trips
  • Model them to forecast demand ridership and revenue
  • Justify them for business case funding
  • Set transport targets
  • Monitor them
  • For use by Government, Local Authorities, consultants, transport operators, research and funding agencies worldwide

The transport planner doesn’t have to wait overnight to get the model’s results, these are high quality tools in a fully integrated Windows environment – and they’re fast, very fast.

Use visual-tm’s transport database to help set your transport targets, monitor your transport plan and ask What..if questions to see what is going to happen. It will even help you keep your models up-to-date.

Models for trip generation, distribution, mode choice, public transport assignment with overcrowding, interchange, delay and capacity restrained highway assignment with junction delay are controlled from simple screens with default parameters and options that you can easily change if you wish.

The models are structured correctly and the software directs you to get the correct outputs for input to the next process. For example the skims from the assignment models are ready for the mode choice model; the log sums from the mode choice model can be put directly into the distribution model and the matrix that comes out of the distribution model goes through mode split and assignment with no messing about.

ERICA – The Department for Transport Matrix Builder

Date: 1991 to Present

ERICA5 is software which builds origin-destination trip matrices from origin-destination (o-d) trip record data, statistically merging it, using DfTs variance weighting methodology. This takes account of double counting, multiple screenline crossings and the problems associated with motorways. The o-d data can include data from roadside, household, on-train or on-bus interviews and pre-existing matrices.

ERICA5 has been developed during a series of important research projects for DfT into matrix building. Initially developed for the ERTM/ SERTM models to hold the extensive London rsi’s, it was used to statistically build consistent trip matrices by merging the origin-destination movements using DfT’s variance weighting taking account of trips, which wiggle across rsi screenlines and the problems associated with motorways. It was extended during the MYSTIC project to hold household data as well as pre-existing matrix data. The merging was extended to allow inconsistent zone specifications and matrices were built from UK datasets in the Southeast, West Midlands, Manchester and Scotland to give National coverage as well as international datasets from the UK, France, Germany, Norway, Sweden, Denmark, Finland and the Netherlands. It was extended on the DATELINE project to build long-distance matrices for the whole of Europe; on the West Midlands PRISM model to cover inferring and on Cheshire County Model to cover merging datasets with different zone systems.

ERICA has been used since 1992 to build matrices for most of the models around London including: ERTM/SERTM, MUM, LASER, NAOMI, LATS, County models in Surrey, Kent and Hertfordshire and various scheme appraisal models. Special versions of ERICA have been developed and are being used in the Census Matrix Tools software, for the DfT’s rail passenger matrix builder, for the European MYSTIC matrices and for the DATELINE long-distance household travel diary database and modelling.

ERICA5 is usually supplied within a special version of Visual-tm (Visual-tm Erica edition or Visual-tm Corporate edition). ERICA5 is the matrix builder and our Visual-tm software is its front-end which provides a user friendly interface for the ERICA5 control files as well as essential functions for cleaning the raw data, coding postcodes to geo-codes and geo-codes to zones, expanding roadside interview data to classified counts, tabulating and analysing the o-d database.

Visual-tm ERICA edition is available for PC’s running 95/2000/XP servers or above. For further information please contact us. ERICA is owned by DfT and contains Peter Davidson’s fast low-level object library for handling very large datasets and very large matrices.

Census Matrix Tools

Date: 1998 to Present

Department for Transport (DfT) commissioned Peter Davidson Consultancy to update the 1991 Census Matrix Tools with the new 2001 ONS National Census, the National Travel Survey and the Labour Force Survey so as to produce up-to-date work trip matrices for transport planners. This work is complete and the resulting 2001 Census Matrix Tools is to be released shortly. The census is an important data source. However there are problems with using the ‘raw’ census data as follows:

  • Census data table entries of 1 or 2 were rounded either up to 3 or down to 0 randomly.
  • When tables at census output area when aggregated to ward level they did not match-up with the ward level tables. Cross tabulations were also randomised in this way.
  • The census asked respondents to give their normal journey to work and on many days people did not make this journey. The census ‘journey’ is inconsistent with our definition of a ‘trip’
  • For many uses, the work trips need to be split by different types of household car ownership
  • Census data is rarely used on its own and variances are needed to combine data sources

The 2001 Census Matrix Tools software overcomes all of these. It produces origin-destination matrices containing the number of trips to work from each home census output area to every workplace census output area in England, Scotland and Wales. (This is a much finer level of detail than the 1991 version, which only went down to ward level). Census output areas can be aggregated to Wards, Districts, Counties or Regions or can be grouped according to any user-defined zone combination. The output is a set of trip matrices representing any year between 2001 and 2003 which can be printed, tabulated, manipulated, put into a spreadsheet, transport database or model.

Trip matrices can be annual averages or for a neutral month. They can be for a neutral weekday, average weekday, Saturday or Sunday. They can be split by mode (e.g. car driver, car passenger, bus, train, tube, walk, cycle, motorcycle) or by car availability: (0 cars, 1 car in 1 adult household, 1 car in a 2+ adults household, 2+ cars). Trip matrices can be Home-to-Work or Work-to-Home. They are provided with their variance (index of dispersion) matrix so that they can be statistically merged with other trip matrices according to the DfT matrix merging methodology.

The census was 100% and is therefore a data source you can’t ignore. The DfT’s 2001 Census Matrix Tools software is set to be a standard reference for preparing LTP’s and monitoring for best value. It has been supplied to DfT, TRL, many of the multimodal studies, consultants, Local Authorities and others. It is available for PC’s running Windows 2000 or above and is priced by DfT at-cost. We can also provide the matrices themselves.


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