What the recommended design maximum is for (a) daily and (b) hourly peak traffic flows for dual (i) two-lane and (ii) three-lane motorways.

There are no recommendeddesign maxima for traffic flows for any category of road in either daily or hourlyterms. The Design Manual for Roads and Bridges (DMRB) Volume 5, Advice Note TA 46/97“Traffic Flow Ranges for Use in the Assessment of New Rural Roads”,sets out opening year flow ranges for use only as starting points in the designand economic assessment of new rural road links. These are as follows:
Carriageway Standard
| Opening Year AADT

Minimum
| Maximum

Dual 2 Lane Motorway
| Up to 41,000

Dual 3 Lane Motorway
| 25,000
| 67,000

Note: AADT is Annual Average Daily Traffic in vehiclesper day.
These flows do not represent maximum throughputs whichdepend on vehicle type mix, driver behaviour, junction spacing, maintenance considerations,etc.
No hourly peak trafficflow ranges are given in the DMRB.