FOI request detail

Road Traffic and Vehicle Compliance Data

Request ID: FOI-1409-2122
Date published: 21 October 2021

You asked

Hello, I would like to request some data for a research dissertation I am working on for university. I am evaluating the Low Emission Zones in London, and I need either hourly or daily measures for road traffic volumes in London, and I would also like to see the number of LEZ compliant and non-compliant vehicles in the LEZ zones, for the past 5 years if possible.

We answered

TfL Ref: FOI-1409-2122

Thank you for your request received by Transport for London (TfL) on 1st October 2021 asking for information about road traffic data in London.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. 

Specifically you asked:

Hello, I would like to request some data for a research dissertation I am working on for university. I am evaluating the Low Emission Zones in London, and I need either hourly or daily measures for road traffic volumes in London, and I would also like to see the number of LEZ compliant and non-compliant vehicles in the LEZ zones, for the past 5 years if possible.”

I can confirm that we hold some of the information you require.

In terms of road traffic volumes, please find attached a list of all Automatic Traffic Counters (ATCs) that we hold inside the LEZ. The spreadsheet contains daily flows recorded for combined direction from all these ATCs between 30 September 2016 – 30 September 2021 from our traffic flow database. Note that the spreadsheet contains multiple worksheets, and that you may need to expand the width of some columns to see the data in full.

In this database raw traffic flow data has been patched at the most granular level when patching is required (due to telecoms issues or physical damage to a recording site) with a substitution value based on historic data. Substitution tables containing the values to be patched are created every month to keep them as up to date as possible. This allows consistent long term trends to be provided for any given automatic traffic counter site within the network.

The spreadsheet contains a pivot table for each year with the sum of daily flows from all the ATCs in the LEZ allowing changes in daily traffic flows to be tracked inside the LEZ for the past 5 years.

In regard to the “the number of LEZ compliant and non-compliant vehicles in the LEZ”, this is not information that TfL captures and so we cannot answer this question.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely,

David Wells
FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London

 

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