Effect of removing non compliant vehicles from ULEZ
Request ID: FOI-2482-2122 Date published: 14 February 2022
You asked
The data I request is very simple but has not been published in any of your reports.
What is the estimated effect of removing all on-compliant vehicles from ULEZ overnight and replacing them with compliant vehicles? That is: what is your calculated percentage reduction of NOX if all non compliant vehicles had been magically replaced with compliant ones overnight?
This calculation is extremely simple if you know the relative proportions of compliant and non compliant vehicles and if you know their relative levels of average NOX emissions in city traffic. Both these parameters must be known to you.
A standard reply referring to the reports in the public domain is not satisfactory because they do not answer the one question.
We answered
Our ref: FOI-2482-2122/GH
Thank you for your request received by Transport for London (TfL) on 30 January 2022 asking for information about the effect of removing non compliant vehicles from ULEZ.
Your request has been considered under the requirements of the Environmental Information Regulations and our information access policy.
Unfortunately we do not hold the information you require - the number requested is unavailable because it is not a scenario that our policies would result in and has never been calculated – no policies make non-compliant vehicles disappear and be replaced by compliant ones overnight– it is not therefore an assessment we have undertaken and we have not calculated NOx emissions representing this.
Our impacts modelling takes into account how users of the zone will respond to the scheme, which enables the estimation of impacts, such as changes to traffic volumes and emissions to be made. The ULEZ does not ban non-compliant vehicles. The charge level for non-compliant vehicles has been set to encourage frequent users of the zone who drive a non-compliant vehicle to change to a compliant one, or consider alternative, less polluting modes of transport. For drivers who make infrequent trips in the zone, it may not be cost effective to upgrade their vehicle to comply with the ULEZ standards, and they may choose to pay the ULEZ daily charge to drive in the zone. To estimate the response for commercial vehicles, we used data on the frequency of entry into the zone, combined with the cost of compliance to determine where upgrading would be the most cost effective course of action. There is a full summary of how we model traffic and emissions impacts in chapter 6 of the Supporting Information Document for the consultation on changes to the Low Emission Zone and Ultra Low Emission Zone at https://content.tfl.gov.uk/ulez-consultation-appendix-i-nov-2017.pdf.
You may wish to calculate numbers by obtaining the Defra emissions factors toolkit for vehicle emissions, and fleet compositions of Euro standards and fuel splits, alongside vehicle kilometres data – all available on the Defra and DfT websites.
If you are not satisfied with this response please see the attached information sheet for details of your right to appeal.
Yours sincerely
Graham Hurt FOI Case Officer FOI Case Management Team General Counsel Transport for London
