Motorists experienced on average nine seconds of delays per mile on the strategic road network (SRN) in the year ending June 2016.
The figure, published by the DfT on 25 August as part of its latest travel time statistics, represents a 1.3% rise on the year ending March 2016.
Average speed on the SRN also fell. Between July 2015 and June 2016, the average speed was 59.2mph, a 0.2% decrease on the previous quarter (year ending March 2016).
The reliability of travel times on the SRN decreased, with 68% more time needed to ensure on time arrival. Measured using the Planning Time Index*, this equates to a 2% increase on the previous quarter.
The SRN consists of the motorways and ‘A’ roads managed by Highways England. All figures are compared to ‘free flow’ traffic and are estimated by using in-vehicle global positioning systems (GPS) observations from a sample of fleet cars.
In terms of individual road type, the average delay on local ‘A’ roads in England in the year ending June 2016 saw a year-on-year increase of 3.8% to 45.2 seconds per vehicle per mile.
Average speed on local ‘A’ roads also fell, down 1.5% on the year ending June 2015.
*The Planning Time Index is the ratio of travel time or the worst day of the month compared to the time required to make the same trip at free-flow speeds.