Project: Speed/Flow Relationships

Reference: R242

Last update: 14/08/2013 09:38:00


To investigate:
- the treatment of over-capacity flows and speeds,
- the incorporation of HGV speed limits in speed/flow relationships,
- the use of relationships in assignment models expressed in terms of pcus or vehicles,
- the importance of hilliness and bendiness on speed/flow relationships.
And to produce:
- a redraft of DMRB 12.2.21 guidance on use of speed/flow relationships.


Target: To provide updated guidance on the use of speed/flow relationships by vehicle type in highway appraisals.

Technical notes for each of the tasks plus re-drafting the existing DMRB 12.2.1 guidance on use of speed flow relationships in highway appraisals.


WSP Development
54 Hagley Road, Edgbaston , Birmingham, B16 8PE
0121 567 2840

Contract details

Cost to the Department: £37,777.00

Actual start date: 01 May 2008

Actual completion date: 30 September 2008