Once you take the m4 exit off the m25 you have warning signs for ULEZ already even though ULEZ is actually only the congestion charge zone and they don't hit it

Once you take the m4 exit off the m25 you have warning signs for ULEZ already even though ULEZ is actually only the congestion charge zone and they don't hit it until they reach Hyde Park roundabout so it's not a stretch to have a lnother ULEZ out in Great West London since people are already fully aware of it. In a perfect world there would be a staged rollout of ULEZ the epicenter being the A312 parkway/GWR roundabout then expanding down Great West Road until you hit the GSK building. As the ULEZ is rolled out, there would be heavy subsidies offered for EVs for residents in that increasing zone. Before all of that though, all local bus operates would have a 5 year age limit on all busses and strict emissions standards enforced. Residents would have the ability to report back and host subsidized air quality sensors+data, there would be a portal to report offending bus routes (just like there are noise abatement reporting procedures set up for airfields). There would be a mass overhaul of the cycle lane network from Southall down to feltham through Hounslow towards Heathrow airport. I would also heavily subsidize Piccadilly line travel for LHR employees and extend the LHR free travel zone for busses up to Hounslow West station & Hayes and Harlington station (right now it's only up to hatton cross and Holiday Inn - people still have to pay to get there and instead just opt to drive). Enforcement of an LHR ULEZ would be at the end of a whole list of measures. Unfortunately due to budget cuts and privatization, a lot of these are not even considered feasible.