Wednesday, 9 September 2026

Breakthrough Agreement: TfL, Unite and Bus Operators Agree New Air Conditioning Upgrade for London Bus Cabs

Driver's cab of the New Routemaster
Photo by Equipmake

Fresh off the wire, Transport for London (TfL) has announced a major agreement to upgrade air conditioning systems for bus drivers across the capital. Given the significance of this update, I have put together a dedicated article to dive deeper into the details surrounding cab air conditioning, how TfL plans to carry out the rollout, and the underlying technical specifications.

This is undoubtedly welcome news for drivers. The heatwaves throughout 2026 have made working conditions appalling for both transport staff and commuters alike.

The Official Announcement

According to Transport for London’s press release:

The Mayor of London, TfL and Unite the Union have reached a groundbreaking agreement to install air conditioning in all bus driver cabs by the end of May 2027. The agreement forms a key part of the work of the ‘Extreme Weather Taskforce’, which brings together representatives from Transport for London (TfL), Unite the Union, London's bus operators and the Greater London Authority to improve working conditions for drivers during periods of extreme weather.

The taskforce was created in response to increasingly frequent extreme weather, with a shared ambition to improve working conditions for drivers and help futureproof London's bus network. It has established a comprehensive programme of work, focused on both immediate mitigations and longer-term solutions, reflecting the commitment of the group to work collaboratively and at pace.

New buses entering the fleet are subject to much more rigorous air conditioning and ventilation standards than older vehicles, which were purchased when the extreme heat seen this summer was less frequent. The taskforce has been working to understand how best to retrofit older buses with heating, ventilation and air conditioning systems more widely across the bus fleet. The taskforce has agreed plans to retrofit all bus driver cabins that do not currently meet the latest modern specifications by the end of May 2027.
Significant progress has already been made with the successful retrofitting of the driver’s cab of a New Routemaster bus with the latest modern ventilation and air conditioning. The bus is currently being trialled in service with encouraging feedback from drivers. The vehicle has also been tested in formal laboratory conditions to test its performance under extreme heat conditions. The trial is central to informing how modern specifications could be delivered across other bus types in London's fleet. A second New Routemaster bus has also been retrofitted with a different system of the same upgraded specification, so that a robust supply chain can be established that can meet the demands of retrofitting the drivers’ cabs of London’s bus fleet. Further testing and assessment work is underway across all other vehicle types that do not have modern ventilation and air conditioning systems.

A number of complementary measures are also being explored, including solar film technology with UV protections, improved driver seating featuring heating and ventilation, enhanced extreme weather planning, access to hydration and welfare facilities, and other practical interventions that can support drivers during challenging weather conditions.

Taskforce members recognise that there is no single solution to the challenges created by extreme weather. Instead, lasting progress will be achieved through genuine partnership working, open dialogue and a shared determination to identify solutions that are practical, effective and sustainable.

The taskforce remains committed to communicating openly with stakeholders as work progresses and will continue to provide updates as significant milestones are reached. While substantial work remains ahead, all partners are encouraged by the progress made so far and by the spirit of collaboration that has characterised the Taskforce since its formation.

Read the full in TfL's Press Release

The Retrofitting Challenge

This represents a major undertaking for TfL and its contracted bus operating companies. As of 31 March 2026, London’s bus fleet totals nearly 9,000 vehicles. While many of the newer zero-emission buses come equipped with up-to-date cab air conditioning, thousands of existing vehicles will still need to be retrofitted.

Given how unpredictable the weather can be, hopefully the newly retrofitted air conditioning units will be fully operational in time for next year's warmer months. Ideally, bus operators outside London will follow suit and retrofit their fleets too, as heat stress in driver cabs is by no means an issue exclusive to the capital.

For those who follow my social media accounts on X and Bluesky, you may recall that I previously shared context from TfL’s Freedom of Information (FOI) releases regarding their heatwave plans:

Transport for London Freedom of Information release: TfL released Tripartite minutes from 2 Apr 2025 to 9 Jul 2026, covering driver welfare, toilet provision, safety, heat, pay and vehicles. Facilities meetings covered toilets. No heatwave Taskforce minutes were held. tfl.gov.uk/corporate/tr...

[image or embed]

— CLondoner92 (@clondoner92.bsky.social) September 1, 2026 at 9:27 PM

Transport for London Freedom of Information release: TfL guidance advises staff to stay hydrated, wear breathable clothing and watch for heat exhaustion. Those affected should be cooled and given water, with medical help sought if symptoms persist or heatstroke develops. tfl.gov.uk/corporate/tr...

[image or embed]

— CLondoner92 (@clondoner92.bsky.social) August 20, 2026 at 5:49 PM

Although separate from bus operations, I also covered the London Underground's hot weather plan for summer 2026.


Examining the New Routemaster Air Conditioning Specifications

To understand how driver cab cooling has evolved, it helps to look at the contract for the New Routemaster vehicles:

SCHEDULE 1: SPECIFICATION FOR DOUBLE DECKER BUS VEHICLES
12.04 Equipment
The driver's cab shall be provided with the following equipment:

(a) A cab air conditioning system which can be manually controlled by the driver
13.02 Heating, ventilation and cooling - performance
The upper deck air cooling will function independently of the driver’s cab air conditioning.
NBfL Specification Schedule 1 Part 2
Appendix 5 - Extract from TfL Standard Bus Specification for NBfL Contract Purposes Only
ATTACHMENT 12
Heating and Ventilation System Operational Settings and Testing Process
All buses must be fitted with a minimum of a fully automatically temperature controlled heating system. No driver cab or engine bay operation should be necessary to adjust or set the passenger saloon heating system during variations of temperature over the summer and winter periods.
Independent driver controlled demisting system and independent driver controlled cab air conditioning.
All double deck buses must additionally be fitted with an automatically temperature controlled upper deck air cooling system.
Manufacturers should set individual sections of the heating and ventilation system to operate at the following targets:
1. Heating
a) Heating
On ≤15˚C, thermostat on gradual shut down within –ve 4˚C
Off ≥15˚C, thermostat fully shut down (no hot water flow)
b) Ventilation
Natural fresh air via opening side windows at all times by passenger selection
2. Cab / Drivers Screen Demisting
Manual driver selection
Capable of independent operation at all times
3. Drivers Cab Air Conditioning
Manual driver selection
Capable of independent operation at all times. However, if the drivers cab air conditioning is on, the upper deck air-cooling may function on a slow setting to balance the cooling system.
4. Air Cooling (Upper Deck Only)
Off <21˚C, fully shut down
On >21˚C, gradual build up to maximum capacity output at 26˚C
A maximum cooling capacity capable of a reduction of 5˚C is required when interior saloon temperature is 28˚C over a 30 minute pull down test as described below.
If Driver’s cab air conditioning is off, upper deck air-cooling will function independently on its automatic temperature settings.
All bus models will be tested in a temperature controlled chamber at a temperature of 28˚c and must achieve the pull down procedure shown below to validate settings and efficiencies.

You can read more about the HVAC system and the New Routemaster files in my previous article.
https://clondoner92.blogspot.com/2026/06/the-new-routemaster-files-directory-of.html

Current Standards: New Bus Vehicle Specification 2.7

Looking at the current New Bus Vehicle Specification (version 2.7), which applies to new vehicles purchased by private operators, the requirements for driver comfort and air quality are much more detailed:

8.2 Heating, Ventilation & Air Conditioning (HVAC)
8.2.1 Drivers Cab
8.2.1.1 Drivers Cab HVAC
• The HVAC system shall keep the driver’s cab air supply and recirculation system completely separate to the passenger saloon system.
• The HVAC system shall be capable of feeding the driver’s cab (DCAB) with 100% fresh air as well as a mix of fresh air and recirculated air, and shall provide an automatic, demand controlled ventilation system that automatically keeps CO₂ levels in the cab below 800ppm at all times. Evidence of this shall be provided as part of the Assessment Protocol detailed in Attachment 9.
• The CO₂ and temperature sensors shall be placed under the dashboard, away from any vents outlet.
Attachment 9A:
7.5.1 Driver’s cab (DCAB)
Driver’s cab cooling must be capable of providing air speed to a minimum of 1m/s, with at least 5 driver selectable fan speed intervals. This shall be measured from a vertical distance of 1.1m from floor level relative to the centre of the driver’s seating position. At each vent outlet, the air velocity shall be no less than 3m/s when all other vents are closed and set at maximum speed.
Visual check/ measurement to ensure that within the driver’s cab:
• Possesses a CO₂ sensor placed under the dashboard, away from the direction of blown air from any vent.
• Possesses air vents capable of providing cooling and heating (via a dial or similar), with direction of air flow manually controllable by the driver from these vents. The driver shall always have full control over whether or not the fresh air is heated or cooled (again via a dial or similar).
• Has a minimum of two of these vents positioned under the steering wheel, with the ability to direct air flow to the driver’s foot level, and a minimum of two further vents positioned above, capable of directing air flow at the driver’s arms and face.
• The driver can independently turn each vent on/off
• Driver’s cab target set point temperatures and associated system output temperature at every 0.5°C interval, with a range covering at least between 15°C and 26°C (interior). The maximum temperature set point allowed shall not exceed 27°C
• Driver shall not need to select AC or Heating mode to achieve the set temperature on one single control panel
• If any vents are fitted to the dashboard, they shall be positioned so that air will not be blown directly to the driver’s hand when holding the steering wheel two sides at middle position.
• Check that two extra vents have been fitted above the driver’s front header panel if the driver’s HVAC is not mounted at lower front of the bus, otherwise a fan shall be fitted there to provide better air flow in front head area.

I previously reviewed TfL's New Bus Specification version 2.7, which aims to keep newer vehicles cool during future heatwaves.

Broader Fleet Implications

TfL continues to set the benchmark for bus specifications across the UK and Ireland, particularly regarding safety standards. In my view, there is no need for TfL to establish its own bus manufacturing company, as I explored in my previous article on whether London needs a bespoke bus. Setting up an in-house manufacturer would be both politically controversial and costly. Instead, sharing these technical specifications with local and regional transport authorities, especially those running municipal companies or franchising schemes, ensures drivers and passengers nationwide benefit from modernised fleets.

Looking ahead, TfL could also evaluate high-capacity vehicle layouts used in cities like Hong Kong and Singapore. Trialling long, tri-axle air-conditioned buses or Singapore-style three-door, two-staircase double-deckers on suitable routes could provide valuable insights for improving passenger flow, accessibility, and climate control across London's bus network.

I would like to extend an invite for you to follow me on X (formerly Twitter) for transport-related updates. You can find me by searching for @CLondoner92 or by clicking on the direct link to my X page here. I am also present on BlueSky and Mastodon. I look forward to connecting with you on these platforms. Thank you for your support.
Posted by at
Labels: , , , , , , ,

Share this page