All supporting statistical tables are updated on a quarterly basis. We provide statistics by region, sub-national transport body and local highway authority which are updated on an annual basis in February.
Statistics on travel time measures on the Strategic Road Network and locally managed ‘A’ roads from data provided commercially by Teletrac Navman. These are produced on a quarterly basis, as an annual report for the previous year in February and subsequent table updates in May, September and November.
These statistics used to monitor road congestion and journey time reliability are compiled from journey time data from in-vehicle global positioning systems (GPS) and flows estimated using automatic traffic counters and the department’s manual traffic count data.