Late October 2016 saw a large number of raised eyebrows as Cllr Richard Lewis was reported to have stated that Leeds did not have a transport problem. In a subsequent article (and further discussions), Richard clarified his comments.
“I wasn’t saying we didn’t have a problem, what I was saying is that compared to some cities which already have tram or transit systems, we don’t have that congestion.
Coun Lewis said his traffic comments were based on Department for Transport figures.
He added: “In comparison with other cities, traffic moves around Leeds at peak times at a fairly reasonable speed, that is based on Department for Transport figures. It is around 24mph
The figures that Richard quoted are from the Department for Transport statistics (CGN0501) which are the annual average speed on local authority managed A Roads. For the Leeds city council area were 23.9mph in 2015 and 23.6mph in 2016. The comments are correct compared to other cities with the average speeds in Leeds being faster. These stats were revised from a previous set of stats (CGN0205) that focused on the monthly average vehicle speeds on local authority managed A Roads in the morning peak only.
There are a number of sources of data that create this data set. A traffic data organisation (TrafficMaster) provides data from users of their navigation and tracking systems as they move through the UK road system. Data is collected with regards to the usage of these roads that allows the figures to be adapted to reflect how busy each road section is (so that fast quiet roads do not unduly influence the average speeds). More information is available on the Department for Transport website.
There is a substantial issue with Richards use of these statistics. The guidance document for these statistics are clear that users of the data should not use them to compare different local authorities.
It is noted that users should not take a direct comparison of the average speeds reported for different local authorities or regions as a measure of the relative levels of congestion within these areas. Physical differences in the types of roads in these areas and their speed limits will also have a large bearing on driving speeds.
As a result, any attempts to compare Leeds with cities such as Newcastle and Manchester are going against the guidance issued with these statistics. Each area has a different road system, with different road layouts and speeds. Also worth noting is that compared to comparable local authorities, Leeds City Council is larger. As a result, the figures for Leeds are more likely to contain higher speed roads (with 40, 50, 60 and 70 limits) that are outside of city centres than other cities. This could make the figures for Leeds appear faster than other cities.
- Leeds City Council – 217 square miles
- Newcastle City Council – 47.7 square miles
- Liverpool City Council – 43 square miles
Only cars, light vehicles and HGVs were reported in the data. Buses are removed because their frequent stop/start work would report slower journey times and speeds. This means that public transport journey speeds are not recorded. Journeys by walking and cycling are also not included. Although the reasoning is logical, it removes a large number of journeys from the average speed statistics. It focuses on the movement of metal boxes rather than average people flows.
It also focuses on A Roads. As a result, many roads are removed from this work key to moving people around Leeds and subject to delay. Focusing on Richard's Pudsey constituency, a vehicle with a TrafficMaster unit that sits in a traffic jam down Richardshaw Lane B6155 will find that this slow journey is not counted. If a frustrated driver measured by TrafficMaster is sat in a traffic jam on an A Road decides to divert on to another road, that section of the journey where they divert on to a different type of road classification is not counted.
So discounting how Richard has used the data, lets look at how the statistics should be used.
Being a measure of average speed during one of the busiest time periods, these statistics allows users to assess the general trends in the level of physical congestion on these roads over time. Reductions in the speeds reported suggest that average congestion levels have increased over the period while increases in speeds suggest general congestion levels have fallen.
If we look at trends and compare those between the cities using percentages, we can gain an indication of how Leeds has managed its A road network compared to other cities.
For Richard, this interpretation of the statistics isn't so good. Looking at a four year period covering the last four years of data in CGN0205.
|City/City Region||May-11 average vehicle morning peak speed (mph)||Jul-15 average vehicle morning peak speed (mph)||Reduction in speed between May-11 and Jul-15 (mph)||Percentage in speed reduction|
|Newcastle upon Tyne||19.1||17.9||1.2||6.3%|
|Greater Manchester (Met County)||18.3||17.2||1.1||6.0%|
|Merseyside (Met County)||21.9||21.3||0.6||2.7%|
Compared to the northern cities that Leeds is usually benchmarked against, the average percentage speed drop from May 2011 to July 2015 was 6.47% based on the former data. This isn't drastically different compared to Newcastle or Sheffield but the higher average speed made it a more noticeable at 1.5mph lost in four years.
Although one year is not the strongest set of data to identify a clear trend, the new dataset shows that Leeds experienced one of the largest percentage falls in average speeds between 2015 and 2016 compared to its peers.
In summary, Leeds is slowing down faster than other cities. However, this is not necessarily the measure we should be focusing on if Leeds is to increase the level of sustainable transport. The focus should be on all journey times for all transport modes and their reliability.