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INRIX Reveals the UK’s Worst Traffic Jams Over the Past Year

1.35 million traffic jams in past year have cost the economy a total of £9 billion

London – October 18, 2017 – New research from INRIX reveals there were over 1.35 million traffic jams in the past year on the UK’s major roads[1], costing drivers an estimated £9 billion. The causes of the five worst queues ranged from fuel spills to broken down lorries.

November 2016 was the worst month in terms of volume with over 169,000 traffic jams on the UK’s major roads – 50% worse than average. However, traffic jams across the month of April proved the most severe, with the research revealing they were 24% worse than average. The year’s worst traffic jam occurred on 4th August 2017 on the M5 Northbound by Junction 20. Traffic tailed back 35 miles at the peak, and the jam lasted 15 hours, resulting in an estimated cost of £2.4 million to road users.

The cost of traffic jams is composed of the value of wasted time, fuel and unnecessary carbon emissions. Estimates were made based on assumptions about trip purpose and the fuel consumption of the average vehicle, with national averages used as a basis for these values.

Dr Graham Cookson, Chief Economist, INRIX commented:

While queuing is considered a national pastime for many Brits, nothing is more frustrating than sitting in traffic and INRIX Roadway Analytics shows it’s a costly activity. Jams can be caused by all kinds of incidents but the INRIX Incident Platform shows that fuel spillages, emergency repairs and broken down lorries contributed to the biggest pile-ups this year.”

As we head into November, the worst month for traffic jams last year, we advise motorists use the latest real-time traffic technology to keep up to date with the situation on the roads.”

Table 1: Monthly Summary of UK Traffic Jams

The ‘average impact’ is calculated by multiplying the average duration of a traffic jam with its average length.

  All FRC 1 and 2 Roads
Month No. of Traffic Jams Impact of Traffic Jams Average Impact
September 16 135,135 12,820,180 95
October 16 136,255 12,664,459 93
November 16 169,931 16,290,137 96
December 16 115,280 11,324,131 98
January 17 101,272 8,346,117 82
February 17 89,925 10,071,818 112
March 17 96,167 10,834,639 113
April 17 71,519 9,207,443 129
May 17 115,546 11,418,822 99
June 17 118,633 12,118,544 102
July 17 104,851 11,163,833 106
August 17 102,895 12,385,246 120
Year to Date 1,357,430 138,645,368 104

Table 2: Worst Traffic Jams in UK in Past 12 Months (excluding Roadworks)

The cost is composed of the value of wasted time, fuel and unnecessary carbon emissions as a result of the delay imposed on drivers by these traffic jams. The costs are estimated by making assumptions about the trip purpose and the average vehicle.

INRIX Ranking Date Road & Direction Junction Duration (Hours) Max Length (Miles) Economic Cost Original Cause
1 04/08/17 M5 – N J10 15 35.9  £2,360,590 Crash / Fuel Spill
2 07/04/17 M6 – N J21 8 31.0  £1,176,400 Emergency Repair
3 25/08/17 M6 – N J17-23 8 26.4  £967,454 Broken down lorry
4 29/11/17 A406 – W A109 15 14.3  £961,595 Crash
5 13/12/17 M6 – N J32 10 20.4  £903,400 Fire / Emergency Repair

 Table 3: The top five worst traffic jams across the UK

INRIX Ranking Date Road & Direction Detailed Explanation
1 04/08/17 M5 – N Two lanes closed and queueing traffic due to crash involving two lorries which created a fuel spill.
2 07/04/17 M6 – N One lane closed, delays and very slow traffic due to emergency repairs
3 25/08/17 M6 – N A number of lanes were closed at various points along the M6 through the roadworks after a number vehicles broke down and required recovery. Debris also found in the road.
4 29/11/16 A406 – W Two lanes closed, severe delays and queueing traffic due to crash. Only one lane open since 08:00, after a crash at 07:30.
5 13/12/16 M6 – N Three lanes closed and queueing traffic due to emergency repairs requiring resurfacing work following earlier trailer fire.



The UK’s worst traffic jams have been ranked by the Impact Factor which is the duration multiplied by the length of the queue; INRIX analysed  the UK’s major roads (motorways, trunk A roads and Principal A roads) covering 12% of the 246,500 miles of roads, but more than a 64% of the traffic volume. Delays caused by scheduled roadworks were excluded.


INRIX is the global leader in connected car services and transportation analytics, a new approach that leverages big data and the cloud to help manage urban mobility. By aggregating a variety of sources and applying intelligence, INRIX delivers comprehensive data and solutions to help move people, cities and businesses forward. Our partners are automakers, governments, mobile operators, developers, advertisers, as well as enterprises large and small.


[1] Refers to the UK’s FRC 1 and 2 roads – Motorway and A-roads

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