DfT - Road Statistics 2009: Traffic, Speeds and Congestion

Road Traffic in Great Britain

• In 2009, the overall motor vehicle traffic volume in Great Britain was 313.2 billion vehicle miles, down by 3.0 billion vehicle miles from last year.
• This 1.0 per cent fall in overall traffic levels (which follows on from a 0.8 per cent fall between 2007 and 2008) is the first time motor vehicle traffic has fallen for two consecutive years since records began in 1949. However, traffic levels in 2009 were 7.9 per cent higher than in 1999.
• Car traffic was 249.0 billion vehicle miles in 2009, making up 79.5 per cent of all motor vehicle traffic. In 2009 car traffic was 0.3 per cent lower than in 2008, but 6.2 per cent higher than 1999.
• Light van traffic fell by 2.2 per cent to 41.4 billion vehicle miles, this was 29.1 per cent higher than 1999. The fall in light van traffic accounted for 0.9 of the 3.0 billion vehicle mile fall in overall motor vehicle traffic between 2008 and 2009.
• In 2009, heavy goods vehicle traffic was 16.4 billion vehicle miles, down 1.5 billion vehicle miles from 2008, an 8.2 per cent fall which left overall heavy goods vehicle traffic levels lower than 1999 (by 6.3 per cent).
• In 2009, 20 per cent of traffic was on motorways, 28 per cent on rural ‘A’ roads, 16 per cent on urban ‘A’ roads, 14 per cent on rural minor roads and 22 per cent on urban minor roads.
• The total length of road in Great Britain in 2009 was estimated to be 245.1 thousand miles. Minor roads made up 87.2 per cent of total road lengths, with motorways and ‘A’ roads accounting for 0.9 per cent and 11.9 per cent respectively.
• Around 1 in every 255 vehicle miles, or 0.39 per cent of all motor vehicle traffic in Great Britain was driven by foreign registered vehicles.

Free Flow Vehicle Speeds in Great Britain

• In the ten years from 1999, the percentage of vehicles exceeding the 30 mph speed limit on built-up roads has fallen for every vehicle type.
• In 1999, 67 per cent of cars travelled at speeds in excess of the limit; by 2009 this dropped to less than half (48 per cent).
• On motorways in 2009, 52 per cent of cars exceeded the 70 mph speed limit. In addition, 16 per cent of cars were recorded as travelling at 80 mph or faster.
• Very few heavy goods vehicles exceeded their speed limit of 60 mph on motorways. However, over 83 per cent of them exceeded the 50 mph speed limit on dual carriageway non-built-up roads and 75 per cent exceeded the 40 mph limit on single carriageway non-built-up roads.
• In 2009, over half of all motorcycles travelled faster than the 30 mph speed limit in built-up areas. Forty three per cent exceeded the speed limit by 5 mph or more.

Congestion and Traffic Speeds on the Inter-Urban Road Network in England

• Average vehicle delay on the slowest 10% of journeys fell to 3.64 minutes per 10 miles from 3.90 minutes per 10 miles between the baseline year ending March 2008 and the year ending April 2010, a decrease of 6.6 per cent.
• The average traffic speed over the whole network rose from 55.3 mph in 2006 to 55.9 mph in 2008, an increase of 0.6 per cent.
• Over 18 per cent of total vehicle delay on the inter-urban road network in England in the year ending March 2010 was experienced on the M25.

Congestion in English Urban Areas

• The average speed of vehicles travelling on key urban roads in England at the height of the school day morning peak is 13 mph;
• Across the ten largest urban areas in England, the average vehicle journey time during the morning peak in 2008-09 was 3 minutes 24 seconds per mile, 6 seconds per mile faster than 2006-07. However journey times on individual route-segments have undergone a broad spread of changes over that period.

Notes

1. Road Traffic in Great Britain - This bulletin provides details of traffic estimates for Great Britain, giving the number of vehicle miles travelled in each year by vehicle type, road category and region. The figures that relate to traffic are measured in terms of vehicle miles; this is sometimes known as the volume of miles, where one vehicle mile is equivalent to one vehicle driving one mile.
2. The 2009 annual estimates published here are mainly based on around ten thousand manual counts, which are combined with data from about 180 Automatic Traffic Counters (ATC) and road lengths to produce overall traffic estimates.
3. It should be noted that changes in traffic are not directly related to changes in congestion. On some quiet roads, traffic can increase substantially with little affect on congestion. On roads where traffic is on the threshold of capacity, a small change in traffic can lead to large changes in congestion. Other road conditions, such as road works, can also affect the capacity of roads.
4. Free Flow Vehicle Speeds in Great Britain - This section looks at the speed of traffic in free flowing conditions on roads in Great Britain during 2009. These statistics provide insight into the speeds at which drivers choose to travel and their compliance with speed limits, but should not be taken as estimates of actual average speed across the road network.
5. To provide data for this chapter traffic speeds have been monitored at 36 sites where a 30 or 40 mph limit applies and at 62 other sites using Automatic Traffic Counters (ATC), deliberately located where external factors which might restrict driver behaviour (including junctions, hills, sharp bends and speed enforcement cameras) are not present.
6. Congestion and Traffic Speeds on the Inter-Urban Road Network - The indicator used to monitor inter-urban congestion is the average vehicle delay, derived from the differences between observed journey times and a reference journey time (the time that could theoretically be achieved when the traffic is free flowing), weighted by traffic flows for each route of the Strategic Road Network (the inter-urban road network made up of motorways and trunk ‘A’ roads managed by the Highways Agency, as well as the M6 Toll). The slowest 10% of journeys are selected for each 15-minute departure time between 6 am and 8 pm for each day of the week, on each of 95 routes.
7. Traffic speeds on the Strategic Road Network for 2006 to 2009 have been produced from the database used for the inter-urban congestion indicator.
8. Congestion and Traffic Speeds in English Urban Areas - The latest figures on urban congestion in the ten largest urban areas are available in Road Traffic and Congestion in Great Britain: Quarter 1 2010.
9. Most analyses in this chapter have been carried out using average vehicle journey time per mile, the average time it takes a vehicle to travel one mile during the weekday morning peak, excluding school holidays, when congestion is highest. Calculations are based on a selection of key routes, important to the functioning of the urban areas; they use journey time data derived from location reports of in-vehicle Global Positioning System (GPS) devices augmented with survey data about the number of vehicles on each route-segment.    

Publication details

Published on 24 June 2010 by Transport Statistics.

Email roadtraff.stats@dft.gsi.gov.uk or congestion.stats@dft.gsi.gov.uk for queries concerning this bulletin.

For information about release of this product see United Kingdom National Statistics Authority.