A nearby appointment can still demand careful timing when much of the route follows local ‘A’ roads. Published figures show that these roads across Great Britain averaged 24.5mph in the year ending June 2026, making distance alone an incomplete basis for choosing when to leave. A journey can be geographically short without being simple to time.

Reading the average

The figure describes average progress across the network; it is not a recommended speed, a target or a forecast for one trip. An individual journey may be quicker or slower, and its pace may differ between parts of the route. Applying 24.5mph directly to the mileage can therefore create an impression of precision that the data cannot support.

The statistics do not provide a specific arrival time, explain the reasons behind slower progress or describe conditions at the moment of departure. The average is better used to challenge an optimistic assumption than to replace it with another rigid calculation. Local distance should not automatically be treated as a short travel time.

Why mileage misleads

A common planning error is to base the whole calculation on the speed expected along the quickest-looking section. This treats every mile as though it will resemble that section and overlooks the distinction between a route’s best stretch and its overall progress. A more realistic estimate needs to cover the complete journey rather than extending one favourable assumption across it.

Provisional estimates show that car traffic across Great Britain increased by 1.6% to 262.7 billion vehicle miles in the year ending June 2026. That is useful national context, but it is a separate measure. It does not explain the 24.5mph local ‘A’-road average, identify what affected a particular route or prove why one journey took longer than expected.

Setting the departure time

Start with a current estimate for the whole route rather than turning mileage into minutes using an assumed cruising speed. Where punctuality matters, keep some flexibility outside the basic estimate. That margin is there to account for uncertainty in the plan; it should not become an expectation that time can be recovered by driving faster later.

  • Check the complete route, not only its longest or fastest-looking section.
  • Review the journey estimate close to departure.
  • Keep any time margin separate from the basic estimate.
  • If the estimate changes, update the expected arrival rather than rushing.

The 24.5mph average cannot tell a driver exactly how long one local trip will take, but it is a useful check against optimistic mileage-based planning. Use the complete-route estimate, review it before leaving and protect the margin when arrival time matters.