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Car Usage in London: Update

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Dear Transport for London,

In Technical Note 14, “ Who travels by car in London and for what purpose?” (https://content.tfl.gov.uk/technical-not...), you use the 2011/12 London Travel Demand Survey to present a number of data points regarding car use in London. These data are used across a number of government reports to show the characteristics of car users. However, since 2012, both car and public transport usage has changed significantly, with car usage in Inner London down 42% while mileage per trip has increased by 30%.

Couple you please provide the following data based on the London Travel Demand Survey for each of 2011/12, 2018/19 (pre pandemic) and the latest year’s survey:

- the average daily trip rates and travel distances for each travel mode, splitting week days from weekends (the current LTDS worksheet aggregates travel distance between weekend and week day)
- for car drivers and car passengers, the average daily trip rates and travel distances for each purpose listed in Technical Note 14 (Work, Education, Leisure, Shopping/Personal, Other)
- similarly, for car drivers and car passengers, the proportion of weekday and weekend travel, by purpose, split by the distance of trip as in Figure 3 of Technical Note 14 (<1k, 1-2k, 2-3k, 3-4k, 4-5k, 5k+)
- finally, could you please replicate figure 4 of Technical Note 14, showing the average number of car driver and car passenger trips per hour split by period of day, differentiating between Weekday and Weekend travel

For each datapoint requested could you show data for Greater London as a whole, Inner London, Outer London and Trips Wholly Within Greater London as within the London Travel Demand Survey workbook (https://content.tfl.gov.uk/ltds-0520.xlsx)

All the above requests should be simple pivot table analyses on the trip sheet data in each survey and this cheap to produce.

Yours faithfully,

B Treloar

FOI, Transport for London

1 Attachment

Dear B Treloar

 

TfL Ref: FOI-0532-2324

 

Thank you for your email which we received on 21 May 2023, asking for
information about car usage in London, split by weekdays/weekends,
different areas of London and different years.

 

Your request has been considered in accordance with the requirements of
the Freedom of Information (FOI) Act and our information access policy.  I
can confirm we hold the information you require.

 

Unfortunately, to provide the information you have requested would exceed
the ‘appropriate limit’ of £450 set by the Freedom of Information
(Appropriate Limit and Fees) Regulations 2004. Under section 12 of the FOI
Act, we are not obliged to comply with a request if we estimate that the
cost of determining whether we hold the information, locating and
retrieving it and extracting it from other information would exceed the
appropriate limit. This is calculated at £25 per hour for every hour spent
on the activities described.

 

We have estimated that it would considerably exceed the cost limit to
provide a response to your current request. The data you have requested is
not readily available; each individual year is held in a separate database
and we would have to run a manual query for each request to extract the
information you require. As each request would need to be repeated for
each of the years requested, by weekdays/weekends, and also by
Greater/Inner/Outer London, this would of course increase the processing
time required to complete your request.

 

To help bring the cost of responding to your request within the £450
limit, you may wish to consider narrowing its scope so that we can more
easily locate, retrieve and extract the information you are seeking; for
example limiting your request to a lesser amount of data split.

 

Although your request can take the form of a question, rather than a
request for specific documents, TfL does not have to answer your question
if it would require the creation of new information or the provision of a
judgement, explanation, advice or opinion that was not already recorded at
the time of your request.

 

Please note that we will not be taking further action until we receive
your revised request.

 

In the meantime, if you have any queries or would like to discuss your
request, please do not hesitate to contact me.

 

Please see the attached information sheet for details of your right to
appeal.

 

Yours sincerely

 

Eva Hextall

FOI Case Officer

 

FOI Case Management Team

General Counsel

Transport for London

 

 

 

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Dear Ms Hextall and Transport for London,

Your response indicates you do not believe the FOI request would not meet the cost limit, citing the need to run a separate manual query for each request. You then say that each request would need to be repeated for each of the years requested, by weekday/weekends, and also by Greater/Inner/Outer London, increasing the processing time. In your response, you do not include a calculation of the time required to action the request and do not give an indication of what data you would be able to make available. This calculation plus appropriate clarification is required as part of the legislation and its absence makes it difficult for me to know how to revise my request to make it fit within the cost limit.

However, given the characterisation of the costs involved within the request, I strongly refute the suggestion that this data would take more than the 17 hours to retrieve than is implied in your response. Your cost calculation hinges on the idea that each request made, including each sub division of the data, would involve writing and then performing a separate query. This is untrue. Each bullet point requested can be performed by a single SQL query; this is four queries in total, each of which would be run on three identically structured databases. As such, you would require four units of time writing queries, and 12 units of time reviewing data.

Without specific knowledge of the data schema used to store the raw LTDS I can't precisely state the required SQL queries, but presuming the database is structured with journey-based survey data in a single table and so that each record contains a single journey, the queries would have the following structure:

Question 1: the average daily trip rates and travel distances for each travel mode, splitting week days from weekends
WeekdayVsSaturdayVsSunday(DayOfWeek), StageMode, TripLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag, COUNT(Trip ID), SUM(TripLength)
FROM LTDS_TripData
GROUP BY(WeekdayVsSaturdayVsSunday(DayOfWeek), StageMode, TripOrRespondentLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag)
... where WeekdayVsSaturdayVsSunday is a trivial SQL function mapping day of week <= 5 to Weekday, day of week = 6 to Saturday, day of week = 7 to Sunday

Question 2: for car drivers and car passengers, the average daily trip rates and travel distances for each purpose listed in Technical Note 14
StageMode, Trip Purpose, TripOrRespondentLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag, COUNT(Trip ID), SUM(TripLength)
FROM LTDS_TripData
GROUP BY(StageMode, Trip Purpose, TripOrRespondentLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag)
WHERE StageMode IN ("Car Driver", "Car Passenger")

Question 3: similarly, for car drivers and car passengers, the proportion of weekday and weekend travel, by purpose, split by the distance of trip as in Figure 3 of Technical Note 14 (<1k, 1-2k, 2-3k, 3-4k, 4-5k, 5k+)
StageMode, Trip Purpose, TripLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag, Buckets(TripLength), COUNT(Trip ID), SUM(trip length)
FROM LTDS_TripData
GROUP BY(StageMode, Trip Purpose, TripLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag, Buckets(TripLength))
WHERE StageMode IN ("Car Driver", "Car Passenger")
... where Buckets is a trivial SQL function mapping the float-classified distance into the buckets used in technical note 14

Question 4: the average daily trip rates and travel distances for each travel mode, splitting week days from weekends
WeekdayVsSaturdayVsSunday(DayOfWeek), HourlyBuckets(TimeOfDay), StageMode, TripOrRespondentLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag, COUNT(Trip ID), SUM(TripLength)
FROM LTDS_TripData
GROUP BY(WeekdayVsSaturdayVsSunday(DayOfWeek), HourlyBuckets(TimeOfDay), StageMode, TripOrRespondentLocationInnerVsOuterLondon, TripWhollyWithinGreaterLondonFlag)
... where HourlyBuckets is shows the integer hour figure of the TimeOfDay field

All three queries above would have to be divided by an appropriate denominator reflecting the number of respondents each year, which would presumably have the form:
COUNT(Respondent), RespondentLocationInnerVsOuterLondon
FROM LTDS_RespondentData
GROUP BY(RespondentLocationInnerVsOuterLondon)

Since the structure of the database should be near-identical between surveys, the time required to adapt the survey questions should be minimal, and as such I would estimate that retrieving the data would certainly take less than seven hours of analyst time, presuming each base query would take at most one hour to write, adding at most 15 mins to lightly adapt the query structure for each year to any small differences in data structure for each year's LTDS data and adding a further hour for collation of the 12 data tables produced. In reality, I would expect a competent data analyst to take significantly less time to create the required queries, but even the very conservative estimate above is within the appropriate cost limits within FOI legislation.

Could you please confirm if with this precise clarification of the data requested the request is within the required cost limits and respond with the requested data; if not, I would like to submit this for Internal Review.

Yours faithfully,

B Treloar

FOI, Transport for London

TfL Ref: IRV-055-2324

Thank you for your email which was received by Transport for London (TfL) on 19 June 2023.

You have expressed that you are dissatisfied with the handling of your request for information under the Freedom of Information Act.

A review will be conducted by an internal review panel in accordance with TfL’s Internal Review Procedure, which is available via the following URL:
https://tfl.gov.uk/corporate/transparenc...

Every effort will be made to provide you with a response by 14 July 2023. However, if the review will not be completed by this date, we will contact you and notify you of the revised response date as soon as possible.

In the meantime, if you would like to discuss this matter further please contact me.

Emma Flint
Principal Information Access Adviser
FOI Case Management Team
Transport for London

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FOI, Transport for London

Dear B Treloar

 

I am contacting you with regards to your email of 19 June 2023. Following
your email a review has been carried out by individuals who were not
involved in the handling of your requests (the panel). You have disputed
the response which was provided to FOI-0532-2324 which advised that your
request was being refused under section 12 of the Freedom of Information
Act (FOIA) due to the appropriate cost limit being exceeded.  Please
accept our apologies for the delay in responding.

 

To confirm your request of 21 May asked the following –

 

In Technical Note 14, “ Who travels by car in London and for what
purpose?”
([1]https://content.tfl.gov.uk/technical-not...),
you use the 2011/12 London Travel Demand Survey to present a number of
data points regarding car use in London

 

- the average daily trip rates and travel distances for each travel mode,
splitting week days from weekends (the current LTDS worksheet aggregates
travel distance between weekend and week day)

- for car drivers and car passengers, the average daily trip rates and
travel distances for each purpose listed in Technical Note 14 (Work,
Education, Leisure, Shopping/Personal, Other)

- similarly, for car drivers and car passengers, the proportion of weekday
and weekend travel, by purpose, split by the distance of trip as in Figure
3 of Technical Note 14 (<1k, 1-2k, 2-3k, 3-4k, 4-5k, 5k+)

- finally, could you please replicate figure 4 of Technical Note 14,
showing the average number of car driver and car passenger trips per hour
split by period of day, differentiating between Weekday and Weekend travel

 

For each datapoint requested could you show data for Greater London as a
whole, Inner London, Outer London and Trips Wholly Within Greater London
as within the London Travel Demand Survey workbook
([2]https://content.tfl.gov.uk/ltds-0520.xlsx)

 

The response which was provided to FOI-0532-2324 advised that the task
facing the Principal Analyst within a specialized team to answer your
request was great due to the fact that the data you seek is not held in
this format and cannot be easily provided. Therefore it would need to be
identified, located and extracted to fulfil your request in its entirety.

 

To provide you with a little more context with regards to your request for
information, s12 of FOIA allows a public authority to refuse to deal with
a request where it estimates that it would exceed the appropriate limit
to-

 

(a) either comply with the request in its entirety or;

(b) confirm or deny whether the requested information is held.

 

The estimate must be reasonable in the circumstances of the case and where
we claim that section 12 is engaged, we should, where reasonable, provide
advice and assistance to help the requestor to refine the request so that
it can be dealt with under the appropriate limit. The relevant Regulations
which define the appropriate limit for section 12 purposes are The Freedom
of Information and Data Protection (Appropriate Limit and Fees)
Regulation.

 

Regulation 4(3) of the Fees Regulations states that a public authority can
only take into account the costs it reasonably expects to incur in
carrying out the following permitted activities in complying with the
request:

 

• determining whether the information is held;

• locating the information, or a document containing it;

• retrieving the information, or a document containing it; and

• extracting the information from a document containing it.

 

Additionally in such circumstances as may be prescribed, where two or more
requests for information are made to a public authority within a
consecutive 60 working day period and where they relate to any extent, to
the same or similar information -

 

(a) by one person, or

(b) by different persons who appear to the public authority to be acting
in concert or in pursuance of a campaign

 

The estimated cost of complying with any of the requests is to be taken to
be the estimated total cost of complying with all of them. We do not have
to make a precise calculation of the costs of complying with a request(s);
instead only an realistic estimate is required.

 

A realistic estimate is one based on the time it would take to obtain the
requested information from the relevant records or files as they existed
at the time of the request, or up to the date for statutory compliance
with the request. We are not obliged to search for, or compile some of the
requested information before refusing a request that we estimate will
exceed the appropriate limit. Instead, we can rely on having cogent
arguments and/or evidence in support of the reasonableness of its
estimate. However, it is likely that we will sometimes carry out some
initial searches before deciding to claim section 12. This is because it
may only become apparent that section 12 is engaged once some work in
attempting to comply with the request has been undertaken. If we do start
to carry out some searches without an initial estimate, we can stop
searching as soon as we realise that it would exceed the appropriate limit
to fully comply with a request and we are not obliged to search up to the
appropriate limit.

 

The panel have liaised with the Principal Analyst within TfL’s Strategic
Analysis team and he has advised that in order to compile the data you
seek would require 162 separate searches to be ran covering 3 different
databases. If we allowed a conservative estimate of 10 minutes per search
to be ran it would equate to approximately 27 hours of staff time and
resource – well in excess of the prescribed 18 hours under FOIA. The
databases where this information is recorded are not as simple as it may
appear and are hierarchical in nature. This means the data needs to not
only be identified and extracted but also be fully reviewed for accuracy
prior to any disclosure. The volume of analysis you are seeking is vast
and there is no other method that we can use to extract and compile the
data other than individual manual searches.

 

Taking into account all of these considerations, the panel agree that to
try and respond to your request in its entirety would be an unjustifiable
diversion of staff time and burden of resource placed on the small team
who are able to respond to these types of requests diverting them from
their core functions Therefore we are satisfied that the threshold for s12
has been met on this occasion. Finally as s12 of the Freedom of
Information Act is not a qualified exemption it does not require
consideration of the public interest test.

 

We appreciate that the above response will come as a disappointment, but
we do hope the above response has provided a better clarity regarding the
information you seek. If you are dissatisfied with the internal review
actions to date please do not hesitate to contact me or alternately you
can refer the matter to the independent authority responsible for
enforcing the Freedom of Information Act, at the following address:

 

Information Commissioner’s Office

Wycliffe House

Water Lane

Wilmslow

Cheshire SK9 5AF

 

A complaint form is also available on the ICO’s website
([3]www.ico.org.uk).

 

Yours sincerely

 

Emma Flint

Principal Information Access Adviser

FOI Case Management Team

Transport for London

[4][TfL request email]

 

 

This message has been scanned for malware by Forcepoint. [5]www.forcepoint.com

References

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1. https://content.tfl.gov.uk/technical-not...
2. https://content.tfl.gov.uk/ltds-0520.xls...
3. http://www.ico.org.uk/
4. mailto:[TfL request email]
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Dear Ms Flint,

As per my correspondence dated the 19th June, the Principal Analyst is clearly incorrect as regards their estimation of costs. Your correspondence states that 162 separate searches must be run in order to generate the data - presumably searches for each of 3 years x 3 areas x 3 days of the week. Although they cite that these data are stored in heirarchical databases, a single query could be constructed for each question for of the years requested, which would presumably follow an identical schema given the near-identical structure of the underlying database. Given that I have provided the overarching query structure which would reduce this request to 12 searches across 3 separate years, it is somewhat worrying the Principal Analyst still states that these will require separate manual searches, as it would indicate an inefficiency of analysis which would if true be hampering TfL's ability to use the data it owns to correctly set and update policy.

The panel states they expect that generating the data originally requested would take 27 hours of staff time under a conservative estimate. While this is plainly incorrect, the FOI Act requires a public body to assist the requester in requesting a subset of data which would be allowed within cost limits.

As such, I would like to revise my request as follows, which would reduce your claimed 27 hours of staff time to between 2 and 6 hours of staff time, by requesting only the data for the latest available year (a 66% reduction), and by asking for a split between weekdays and weekend days, rather than splitting weekdays from Saturday from Sunday (a 33% reduction). Furthermore, I will rescind my request for the final set of data, by-hour car trip data, in case in the opinion of the Principal Analyst this is driving a disproportionate amount of the manual queries they believe they would need to run. My expectation is that this will have reduced the amount of work the team believe would be required by at least 93%, which would imply a time to deliver of 2 hours. Presuming your initial estimates of time to deliver were correct, this would plainly sit within the 18 hours prescribed under FOIA.

My revised freedom of information request is as follows:

Could you please provide the following data based on the London Travel Demand Survey for the latest year’s survey:

- the average daily trip rates and travel distances for each travel mode, splitting week days from weekend days (the current LTDS worksheet aggregates travel distance between weekend and week day)
- for car drivers and car passengers, the average daily trip rates and travel distances for each purpose listed in Technical Note 14 (Work, Education, Leisure, Shopping/Personal, Other)
- finally, for car drivers and car passengers, the proportion of weekday and weekend travel, by purpose, split by the distance of trip as in Figure 3 of Technical Note 14 (<1k, 1-2k, 2-3k, 3-4k, 4-5k, 5k+)

For each datapoint requested could you show data for Greater London as a whole, Inner London, Outer London and Trips Wholly Within Greater London as within the London Travel Demand Survey workbook (https://content.tfl.gov.uk/ltds-0520.xlsx)

A full history of my FOI request and all correspondence is available on the Internet at this address: https://www.whatdotheyknow.com/request/c...

Yours sincerely,

B Treloar

FOI, Transport for London

Dear B Treloar

TfL Ref: 1330-2324

Thank you for your request received by Transport for London (TfL) on 26 July 2023. .

We will aim to issue a response by 22 August 2023 in accordance with the Freedom of Information Act 2000 and our information access policy.

We publish a substantial range of information on our website on subjects including operational performance, contracts, expenditure, journey data, governance and our financial performance. This includes data which is frequently asked for in FOI requests or other public queries. Please check http://www.tfl.gov.uk/corporate/transpar... to see if this helps you.

We will publish anonymised versions of requests and responses on the www.tfl.gov.uk website. We will not publish your name and we will send a copy of the response to you before it is published on our website.

In the meantime, if you would like to discuss this matter further, please do not hesitate to contact me.

Yours sincerely

Jasmine Howard
FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London
 

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FOI, Transport for London

2 Attachments

Dear B Treloar,

 

TfL Ref: 1330-2324

 

Thank you for your request received by Transport for London (TfL) on 26
July 2023 asking for information about data based on the latest London
Travel Demand Survey.

 

Your request has been considered in accordance with the requirements of
the Freedom of Information Act and our information access policy.  I can
confirm that we hold the information you require. You asked: for

 

data based on the London Travel Demand Survey for the latest year’s
survey:

 

- the average daily trip rates and travel distances for each travel mode,
splitting week days from weekend days (the current LTDS worksheet
aggregates travel distance between weekend and week day)

 

- for car drivers and car passengers, the average daily trip rates and
travel distances for each purpose listed in Technical Note 14 (Work,
Education, Leisure, Shopping/Personal, Other)

 

- finally, for car drivers and car passengers, the proportion of weekday
and weekend travel, by purpose, split by the distance of trip as in Figure
3 of Technical Note 14 (<1k, 1-2k, 2-3k, 3-4k, 4-5k, 5k+)

 

For each datapoint requested, could you show data for Greater London as a
whole; Inner London, Outer London and Trips Wholly Within Greater London
as within the London Travel Demand Survey workbook
([1]https://content.tfl.gov.uk/ltds-0520.xlsx)

 

Please see the attached spreadsheet for the requested data based on the
most recent London Travel Demand Survey, covering the financial year of
2022/23.

 

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

 

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

 

 

Jasmine Howard

FOI Case Officer

FOI Case Management Team

General Counsel

Transport for London

 

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We don't know whether the most recent response to this request contains information or not – if you are B Treloar please sign in and let everyone know.