FOI request detail

Freedom of Information request - Taxi Emission Data

Request ID: FOI-2165-1819
Date published: 14 December 2018

You asked

We are a group of students from the University of Nottingham carrying out an investigation of the impact the new TX electric taxi on the mitigation of climate change. Would it be possible for you to supply us with emission data for both new electric and old diesel model taxis in London in order to help us complete our investigation? We aim to carry out a critical analysis on the impact a new fleet of electric taxis would have on reducing CO2 transport emissions in the capital. Findings from this will be evaluated to see the contribution this change could make in enabling the UK Government reduce UK emissions in accordance with the Paris Agreement targets. Any data you could supply us with would be much appreciated. Equally we are happy to share our findings with you at the end of our investigation.

We answered

Our ref: FOI-2165-1819/GH

Thank you for your request received by Transport for London (TfL) on 16 November 2018 asking for information about taxi emissions.

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

Transport for London has not yet been able to carry out emissions testing of an electric TXe taxi over ‘real-world’ duty cycles, so we do not currently hold the data to inform your request.

Official CO2 and air quality emissions are available publically on the Vehicle Certification Agency website at

The TX4 diesel taxi has CO2 emissions of 222g/km measured on the NEDC cycle, whilst the TXe has 24g/km over the same cycle. However, it is not reliable to use this comparison since the NEDC cycle is unrepresentative of urban taxi operations and also because the TXe emissions, whilst measured in accordance with EU regulation 100, will be dependent on battery state-of-charge, which is unpredictable in real world operating conditions.

In order to conduct the comparison that you are undertaking, it would be better to refer to emissions factors published by Defra in the Emissions Factors Toolkit available at It is common practice to use factors for an N1 class iii diesel light commercial vehicle to represent a diesel taxi as the kerb weight and rolling resistance are similar. To represent the TXe, factors for a large petrol electric saloon car should be used. It might help to consider that the average road speed in Central and Inner London is 14 to 22km/h and that taxis can experience lengthy periods of idling.

You may find some TfL published reports on this subject to be helpful. Please see the links below.

If this is not the information you are looking for, or if you are unable to access it for some reason, please do not hesitate to contact me.

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

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