So, we arrive at Judgement Day for Sadiq Khan’s time as Mayor of London. And we’re being asked to judge him solely on whether we think the Ultra-Low Emissions Zone (ULEZ) is a successful policy intervention or not. His Conservative opponent, Susan Hall, certainly doesn’t think so and has promised to scrap the expanded ULEZ on her first day in office.
I’ve written before about how the Conservative party has weaponised ULEZ instead of seriously thinking about how government and Mayor can work together to achieve the intent behind this policy. Obviously that’s not going to happen but it’s still disappointing to have seen the Mayoral election reduced to a referendum on ULEZ.
Having crunched the data before it is only right to see whether we can gauge the success of ULEZ in terms of its impact on car ownership in London. Fortunately the Department for Transport have published an updated version of the veh9901 dataset (here’s the dataset I used for this post, captured in the Web Archive) that takes us through to September 2023.
And having looked at the data (which includes an 8 month lag don’t forget) it’s such a pity that we spend so much time listening to people having to defend or attack ULEZ rather than recognising ULEZ as a successful policy intervention because its achievements are significant, to the extent that I’m doubting my sums.
I’ve used the same methodology as the other posts in this series. I use ONS Upper Tier Local Authority to differentiate between original ULEZ and expanded ULEZ. I treat non-compliant petrol as those registered in 2005 or before and non-compliant diesels as those registered in 2014 and before. There are exceptions (like our 2004 Focus which is compliant) but this works for my purposes.
According to the latest data is ULEZ successful, or a failure?
In the 18 months since my baseline data there has been an overall reduction in the number of private cars registered to London addresses. It’s only 49,974, a fall of just 2.1%, but worth mentioning nonetheless.
The total reduction in petrol and diesel vehicles of 125,978 is much larger than that first fall, indicating the transition away from the internal combustion engine (maybe I’ll go back and look at those trends another time).
There is a significant drop in the most polluting diesels. Back in March 2022 old petrol, old diesel and new diesel each constituted around 11% of the total private cars in London. While non-compliant petrol engines still represent 8.9%, non-compliant diesel engines have fallen to 4.9% of the total.
| London (total), September 2023 (with change from March 2022) | Total | + / - | % | + / - |
|---|---|---|---|---|
| Private cars | 2,406,694 | -49,974 | | |
| Petrol (registered up to 2005) | 214,307 | -66,111 | 8.9 | -2.5 |
| Petrol (registered from 2006) | 1,493,643 | +69,649 | 62.1 | +4.1 |
| Diesel (registered up to 2014) | 117,325 | -154,455 | 4.9 | -6.2 |
| Diesel (registered from 2015) | 298,141 | +24,939 | 12.4 | +1.3 |
| | | | | |
| ULEZ chargeable private cars | 331,632 | -220,566 | 13.8 | -8.7 |
If we look at Inner London, the original jurisdiction for ULEZ, there has been an overall reduction in private cars of 15,952 with sizeable falls in both categories of non-compliant cars.
This has increased the proportion of private cars exempt from paying ULEZ to 86.3% from a figure of 81.3% in March 2022. This means that out of the 631,236 private cars in Inner London, 86,677 of them are non-compliant when 18 months previously the figure was over 120,000.
| London (Inner), September 2023 (with change from March 2022) | Total | + / - | % | + / - |
|---|---|---|---|---|
| Private cars | 631,236 | -15,952 | | |
| Petrol (registered up to 2005) | 59,650 | -17,458 | 9.4 | -2.5 |
| Petrol (registered from 2006) | 386,361 | +34 | 61.2 | +1.5 |
| Diesel (registered up to 2014) | 27,027 | -16,791 | 4.3 | -2.5 |
| Diesel (registered from 2015) | 76,298 | +3324 | 12.1 | +0.8 |
| | | | | |
| ULEZ chargeable private cars | 331,632 | -34,249 | 13.7 | -5 |
In Outer London this is the first time I’ve crunched numbers that reflect the actual impact of ULEZ as opposed to projecting the consequences from its future expansion.
And it’s a further resounding endorsement for the success of the policy in shaping behaviour with the proportion of vehicles exempt from ULEZ in Outer London almost identical to that of Inner London at 86.2%. Only 18 months ago the figure for Outer London was 76.2%. This means that out of 1,775,458 private cars in Outer London, 244,955 have been paying the ULEZ charge. 18 months ago that would have been 431,272.
You can see why I was doubting my maths: it appears that the prospect of paying the ULEZ charge has removed almost 200,000 of the most noxious vehicles from the streets of London in just 18 months. Indeed, across London as a whole there were 552,198 ‘problem’ cars in March 2022 comprising 22.5% of all private cars in London. 18 months later only 331,632 remain.
| London (Outer), September 2023 (with change from March 2022) | Total | + / - | % | + / - |
|---|---|---|---|---|
| Private cars | 1,775,458 | -34,022 | | |
| Petrol (registered up to 2005) | 154,657 | -48,653 | 8.7 | -2.5 |
| Petrol (registered from 2006) | 1,107,282 | +69,615 | 62.4 | +5.1 |
| Diesel (registered up to 2014) | 90,298 | -137,664 | 5.1 | -7.5 |
| Diesel (registered from 2015) | 221,843 | +21,610 | 12.5 | +1.4 |
| | | | | |
| ULEZ chargeable private cars | 244,955 | -186,317 | 13.8 | -10 |
Whichever way you look at these numbers I think you have to conclude that ULEZ is a successful policy intervention.
This is why the insistence of Susan Hall and her campaign to make these mayoral elections a referendum on ULEZ is bizarre. We’re actually 40% of the way towards nobody paying ULEZ on their private cars anyway. And really there is no good reason why an issue which affects 331,632 private cars in a city of 9 million should have become such a prominent feature of our public discourse, and yet here we are.
At least if Sadiq Khan wins the election I’m sure we won’t hear anyone talking about ULEZ anymore…