You recently implemented a change from 30mph to 20mph on all TFL roads in inner London. https://tfl.gov.uk/corporate/safety-and-security/road-safety/safe-speeds What was the full cost of this scheme? Your website talks about collisions. Please release the collision data on the affected corridors before implementation. Your website says "We'll continue to monitor the effectiveness of these measures in lowering speeds, so we can determine if more design changes are needed" Please release the data you are using for this. How will you be measuring the success of the scheme? What budget do you have for the second phase?

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TfL Ref 1699-2021

Thank you for your request received by Transport for London (TfL) on 25 November 2020 asking for information about the London 20mph project.

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 some of the the information you require. Your request and the information you asked for is as follows:

You recently implemented a change from 30mph to 20mph on all TFL roads in inner London: https://tfl.gov.uk/corporate/safety-and-security/road-safety/safe-speeds

What was the full cost of this scheme?

• The outturn cost of the project to convert TfL roads to 20mph operation inside the congestion charging zone was £2.5m.

Your website talks about collisions. Please release the collision data on the affected corridors before implementation.

• Please see below the 36 months of collision data collected to December 2017. This data represents the pre-implementation data that we collected for the proposals and used to develop the business case. It  covers the period January 2015 to December 2017.

Name	Description	Months	Total	Fatal	Serious	Slight
20INNER_CORRIDOR_01	Millbank	36	24	0	4	20
20INNER_CORRIDOR_02	A3036 Albert Embankment	36	35	0	1	34
20INNER_CORRIDOR_03	A3211 Victoria Embankment	36	138	2	22	114
20INNER_CORRIDOR_04	A3211 Upper Thames Street	36	42	0	6	36
20INNER_CORRIDOR_05	A3211 Lower Thames Street & Tower Hill	36	67	0	11	56
20INNER_CORRIDOR_06	Aldgate	36	131	1	21	109
20INNER_CORRIDOR_07	Great Dover Street	36	41	0	3	38
20INNER_CORRIDOR_08	Borough High Street	36	68	0	5	24
20INNER_CORRIDOR_09	Tooley Street / Crucifix Lane / Druid Street	36	61	0	7	54
20INNER_CORRIDOR_10	Blackfriars Road	36	48	0	6	42
20INNER_CORRIDOR_11	Lambeth Bridge	36	108	2	10	96
		Totals	763	5	96	623

Your website says "We'll continue to monitor the effectiveness of these measures in lowering speeds, so we can determine if more design changes are needed"

Please release the data you are using for this.

• We will be monitoring 36 months of collision data by monitoring the number of collisions that take place and the number of each severity as split down by each of the categories the data is presented in: fatal, serious and slight. We would normally monitor data for the immediate 36 months following implementation, so April 2020 to March 2023, however, we will need to consider whether data collected during the coronavirus pandemic period is a fair comparison. We therefore do not hold this data at this time.

From 2 March 2020, the roads we operate and manage within the central London Congestion Charging Zone had a new speed limit of 20mph. Collision data from around the world is very clear. It shows that the faster a vehicle is travelling:

The more likely a collision will occur because the driver has less time to react, stop or avoid the collision

The more severe an injury resulting from the collision will be

For example, if you hit someone at 30mph they're five times more likely to die than if you hit them at 20mph. That's why this new limit is so important and why we ask for drivers to watch their speed as they’re driving through central London.

The Metropolitan Police enforce all speed limits in London. They do this using on-street officers, mobile speed cameras and fixed speed cameras. In 2018, 154,785 people were caught and penalised for speeding related offences, including 38,878 on 20mph limit roads.

The Metropolitan Police will continue enforcing all speed limits across London, including where new speed limits are in place.

There are many different ways to encourage people to drive at lower speeds, but evidence shows that self-enforcing speed limits are the most successful way to reduce speeds.

A self-enforcing speed limit means that people are more likely to drive within the signed speed limit because they feel it's the easiest and safest speed to drive along that road. This is generally because of the way the road looks and has been designed.

Some of the design and engineering measures used to lower speeds are:

• Signs
• Road markings
• Speed cushions
• Speed bumps
• Raising pedestrian crossings
• Widening footways for people walking
• Giving more space to people cycling
• Removing the white line in the centre of a road
• Changing the surface of the road
• Creating curves along the road that requires vehicles travelling in different directions have to slow down or give way
• Introducing more traffic islands in the centre of the road
• Placing trees, planters and parklets along the roadside or in the centre of the road

There's no 'one size fits all' approach to reducing vehicle speeds. We use different measures depending on the type of road, who uses the road and the road space available.

We'll continue to monitor the effectiveness of these measures in lowering speeds.

How will you be measuring the success of the scheme?

• We will be considering the change in speeds recorded on our network and the change in fatal and serious collisions that occur. Changes on our network during 2020 may be due to the worldwide Coronavirus pandemic, and analysis will be undertaken to identify where this is the case.

What budget do you have for the second phase?

• We currently have £1.5m funding approved in 2020/21 to commence design work on phase 2 of the project.

If you are considering submitting a further FOI request please think carefully about whether the request is essential at this current time, as answering FOI requests will require the use of limited resources and the attention of staff who could be supporting other essential activity. Where requests are made, please note that our response time may be impacted by the current situation.

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

Sara Thomas

FOI Case Management Team

General Counsel

Transport for London

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