What is TRICS and how does it work?

The System

TRICS® is the system that challenges and validates assumptions about the transport impacts of new developments

TRICS® is the system of trip generation analysis for the UK and Ireland. First launched in 1989, it is an integral and essential part of the Transport Assessment process, and through continuous investment and development it has expanded into a comprehensive database of traffic and multi-modal transport surveys, covering a wide range of development types.

The system allows its users to establish potential levels of trip generation for their development scenarios using a series of database filtering processes, and it is widely used by both transport planning consultants and local authorities (the latter of which use TRICS® to audit Transport Assessments).

The TRICS® database includes over 8,000 transport surveys. In addition to inbound and outbound traffic and multi-modal counts (covering a wide range of separate count and mode types), the TRICS® site records include comprehensive descriptive detail on a site's local environment and surroundings, information on the size, composition and functions of a site, and details of on-site and off-site parking facilities. Large annual regional data collection programmes across all parts of the UK and Ireland ensure that new transport surveys are continuously added to the database.

As well as being a database of transport surveys, TRICS® is also a system that allows its users to apply inclusion criteria to calculate trip rates for their various development planning scenarios, and they can do so through a number of progressive and user-friendly filtering stages. TRICS® is constantly reviewed, and through a successful interactive and inclusive approach, feedback from member organisations assists in the constant development of new system features and enhancements. The system also includes an easily accessible directory of help files to assist users in their understanding of the database and its operations.

TRICS® Consortium Limited is a company wholly owned by Dorset Council, Hampshire County Council, East Sussex County Council, Kent County Council, Surrey County Council, and West Sussex County Council. These local authorities constitute the Board of the company, and TRICS is project managed and delivered by a separate team of management and technical staff based in London.

What is the best way to use TRICS®

The TRICS® Good Practice Guide provides detailed guidance on all elements of the TRICS® system procedures and its survey data, and is considered essential reading by all user organisations. It has been written to encourage users to operate the system and present its data in the most correct way, and it is also a very handy reference for those tasked with auditing TRICS® results that are presented in Transport Assessments and other documents.

View the current version of the TRICS® Good Practice Guide here

Using the System

TRICS® supported browsers
  • macOS 11/12/13/14: Safari/Chrome
  • Windows 10/11: Microsoft Edge/Chrome
TRICS® Offline Version
  • This can be installed as a service onto a Windows PC running Windows 10 or 11.
  • It requires 700mb of disk space and 200mb of RAM.
  • The Offline version cannot be installed on a Mac.

TRICS® directly commissions a large annual data collection programme of traffic and multi-modal surveys across all regions of the UK and Ireland, covering a wide variety of development types. This ongoing commitment to comprehensive continuous data collection programmes is what makes TRICS® the standard system of trip generation analysis.

We can also manage and deliver individual TRICS® surveys upon request, as a direct commission from any organisation. Working with our TRICS®-approved data collection contractors, this process involves undertaking site visits, producing detailed survey specifications, undertaking the multi-modal survey counts, and the subsequent delivery of a set of survey results to a fully TRICS®-certified standard (following a comprehensive process of validation testing). Numerous organisations commission TRICS® to manage and deliver surveys at a wide range of development types for the purposes of travel plan monitoring. This process is known as SAM (Standardised Assessment Methodology).

Organisations can also supply their own surveys should they wish them to be certified as TRICS®-compliant. Our multi-modal data collection methodology and data collection standard can be adopted should an organisation wish to manage and undertake a survey themselves, and such surveys would be considered TRICS®-compliant following the subsequent data input and validation process undertaken by the TRICS® team. This data would then be added to the TRICS® database, and the input and validation fees for these surveys are £160 + VAT for a traffic count, £207 + VAT for a multi-modal count, and £266 + VAT for a multi-modal count with travel plan information included. Your survey data being certified as TRICS®-compliant would be of great benefit to your organisation as it would receive recognition of compliance from the standard system of trip generation analysis that is widely recognised around the UK and Ireland (subject to your data being successfully validated of course). You would also receive a certificate of TRICS®-compliance upon the process being completed. The TRICS® multi-modal methodology document can be downloaded here

If an organisation is tasked with calculating potential traffic and transport generation for a future proposed development, then they can use TRICS® to undertake this exercise. The system has a lot of data contained within it as surveys have been continuously undertaken over a long period of time, and as a result it is very flexible, allowing users to operate a wide range of database filtering processes. The system is designed to take users through progressive stages of this filtering, starting off with the full database for a selected development type until all of the compatibility criteria (decided upon by the user) have been met, with users ending up with a smaller, compatible set of surveys ready to undergo a trip rate calculation. The result is a range of trip generation rates for a development scenario, which can then be used in a Transport Assessment.

Individual trip rates for a survey period for a set of surveys can also be calculated and ranked in order of relative trip rate intensity, in what we call a rank order list. Accompanying trip rate graphs and rank order scatterplots can provide users with visual representations of peak trip activity and visual relationships between trip rate calculation parameters (for example Gross Floor Area, Number of Dwellings, etc) and trips.

As the TRICS® database is large (currently over 8,000 survey days), it is important that its users are provided with an easy method of system navigation. When using TRICS®, users can select to view database site lists by choosing their required development type. TRICS® provides user-friendly drop-down menus for this purpose.

When viewing individual site records from site lists, a system of icons and tabs allows users to move freely through the comprehensive set of descriptive information that accompanies the survey counts. Separate screens within a site record display site location information, details on local public transport accessibility, design features encouraging non-car modes of transport, development details such as the size and functions of a site, and information on on-site parking and local off-site parking availability. All of this is supplemented by further descriptive detail in dedicated comment areas within individual sites, so users can get a thorough picture of where a site is, its local environment, and what it consists of.

The trip rate calculation process also follows a logical process of filtering, broken down into easy-to-follow stages leading up to the actual calculation once users are satisfied with their selection criteria. It is important for us that movement through the system at all its stages is fluid and user-friendly, and we are constantly developing and refining the system to ensure that this remains the case.

TRICS® users undertake trip rate calculations using a number of calculation parameter options (for example Gross Floor Area, Dwellings, Employees, etc), to ascertain potential levels of trip generation for a user-defined development scenario.

What are trip rates?

Trip rates show the number of traffic/people movements to and from a development (or an average for selected developments within the same land use sub-category), for a selected trip rate parameter factor. For example, when trip rates are calculated by Gross Floor Area (GFA), they are presented per 100m2 of GFA. Using this factor, users can apply trip rates to their development scenarios, and are encouraged to achieve a balance between their selection criteria and the size of their selected data sample to achieve this.

How are they calculated?

Average (mean) trip rates are calculated when there are at least 2 surveys included in a selected set (trip rates for an individual site can also be calculated). The calculation process consists of 3 parts, and these apply to every period of the survey duration, split by inbound, outbound, and total (two-way) trips.

Surveys at sites that have the necessary count data available for a particular period (those that include arrivals and departures count data for the period) are used throughout this procedure. The GFA (for example) figures of the sites are added up, with the total GFA then divided by the number of surveys in the included set, to produce the average (mean) trip rate parameter figure (represented here by mTRP).
The same selected surveys used in stage 1 are also used in stage 2, these being surveys that include arrivals and departures count data for a particular survey period. The ARRIVALS figures from the selected surveys during the period are added up, with the total number of ARRIVALS then divided by the number of surveys in the included set, to produce the average (mean) ARRIVALS count figure (represented here by mARR). The same process takes place for DEPARTURES and TOTALS (so represented by mDEP and mTOT).
The following expression is used to calculate the average (mean) ARRIVALS trip rate by GFA for a particular survey period, with m representing mean:

(mARR / mTRP) X 100

This calculates the average (mean) trip rate per 100m2 of GFA, and this figure is then shown within the trip rate calculation results table. The calculations for DEPARTURES and TOTALS are similar, as shown below:


TOTALS = (mTOT / mTRP) X 100

This method calculates the trip rate per 100m2 of GFA for any survey period. Note that the calculation factor (100m2 in the case of GFA) varies, depending on the trip rate parameter used (e.g. per dwelling, per employee, per hectare, etc).

Trip rate graphs that provide a visual representation of the trip rate results table can also be produced at a single click, and can be used to identify percentages of trips per period as a proportion of the whole survey duration, as well as indicate periods of peak trip activity.

Trip rate rank order lists display the trip rate value (either arrivals, departures or totals) for each individual survey included in the original trip rate calculation, with the survey with the highest relative trip rate (per calculation factor) shown at the top of the list. Rank order list trip rates are calculated for a selected period, including each individual survey in a selected set, so are a good way to view trip rates for on a like-for-like basis without any averaging taking place, also providing a good example of the range of trip rates through a selected set of surveys.

Note that trip rates can be calculated for the whole range of different TRICS® count types, for example Total Vehicles, Pedestrians, Public Transport Users, Total People.

The TRICS® system is updated on a quarterly basis and automatically updates on-line. Typically, updates of the system are made live within the months of March, July, September, and December.

Ongoing development of the system takes place through an inclusive and interactive approach that encourages the input of our member organisations, collectively known as the TRICS® Community. Through our popular annual User Meetings and Training & Development Forums, responses to our annual User Surveys, and through direct correspondence with our users, the system is continuously developed and improved. When new versions of the system are ready to go live, users are notified of all system changes and new surveys that have been added to the database.

An annual, comprehensive programme of data collection, covering all regions of the UK and Ireland, also means that new surveys are usually added to the database at the time of each update. All data supplied to TRICS® by our approved data collection contractors is subject to thorough, stringent validation procedures, with no new data being accepted into the database until all our validation testing criteria has been met. This ensures that TRICS® data remains of the highest quality.

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