Project: Analysis and Collection of Robust Motorway Variability Data

Reference: H133A

Last update: 15/08/2013 16:26:02


The objective of this project is to gain results that lead to improved transport modelling advice and a more realistic estimation of the relationship between journey time variability and traffic volumes.


This project intends to deliver a series of six working paper reports for use in updating INCA setting out, summarising and justifying, the following:

1. relationships between vehicle kilometres and incident numbers;
2. capacity loss passing incidents;
3. methods of representing division behaviour;
4. how to represent a range of build up durations by a number of typical incidents;
5. how to extend the methodology to all purpose roads;
6. a final report including advice on updated parameters for use in INCA.


TRL Limited
Crowthorne House, Nine Mile Ride, Wokingham, Berkshire, RG40 3GA
+44 (0)1344 773131

Contract details

Cost to the Department: £181,024.00

Actual start date: 12 March 2003

Actual completion date: 30 March 2005


Updating & validating parameters for incident appraisal model INCA
Author: BA Frith, J Fearon, TE Sutch, & G Lunt
Publication date: 17/05/2005
Source: DfT website
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