Motorways and ‘A’ roads managed by the Highways Agency are known as the strategic road network.These strategically important roads account for around 2% of all roads in England, but carry around a third of all traffic. The reliability of journeys on the Highways Agency’s roads is measured by the percentage of journeys that are ‘on time’, where:

• · A ‘journey’ represents travel between adjacent junctions on the network;
• · An ‘on time journey’ is defined as one which is completed within a set reference time, based on historic data on that particular section of road.

• In the year ending January 2013, provisional data shows that 78% of journeys on the Highways Agency managed network were ‘on time’. This is 0.6 percentage points lower than the previous year, ending December 2012.

•  Provisional data shows that 73.5% of journeys on the Highways Agency network  during January 2013 were ‘on time’, down 7.3 percentage points from January 2012. 

The data are based on journey times estimated using in-vehicle Global Positioning Systems (GPS) and flows estimated using automatic traffic counters.