Supplementary memorandum by West Midlands
Chief Engineers & Planning Officers Group (RP 48)
COMMITTEE EVIDENCE SESSION 19 JANUARY: FOLLOW
UP TO QUESTION 337
The figure of £2.3 billion for the cost
of congestion was derived from two sources. Initially the CBI
produced a national estimate and then pro-rated this to different
areas based on their contribution to GDP.
We then ran a check on their figure using the
West Midlands Traffic Model. The free flow speed of the network
was generated for each road link. An "uncongested" am
peak total was calculated. This peak was then modelled under normal
circumstances. The cost of congestion was derived from the difference
between the two. This was repeated for both the pm peak and off
peak periods.
These results were converted to an annual figure
using standard DfT representative flow groups.
The result was a figure of £2.3 billion
at 1999-2000 prices which was close to the original CBI estimate.
David Bull
Chair
16 February 2005
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