Have you ever actually been to Hillingdon or tried to get around it by public transport? There are farms in Hillingdon and villages with poorly joined up and intermittent, slow bus services at best.
The transport, like most transport inside the M25 is primarily designed to get you into central London. Fine if you are off to the city in the morning and corporate spouse can drop you off at the station. Useless if you work shifts or locally or in Bucks/Berks/etc as most people do in that part of the world. Most people need to drive to get to work, schools and childcare (unless they have half a day to do the journey).
The constituency is also exactly the demographic which both the Tories and Labour need to win - pockets of significant deprivation, some areas of affluence and a large chunk of those who are self employed, on zero hour contracts, the "just about managing", the first generation owners of modest homes, hospital workers, carers, airport shift staff.
Its a swing seat under the new boundaries tested first by Johnson, who won partly on his record against Heathrow expansion (which he then hid from) and as part of a country wide swing to the Tories.
Khan is imposing ULEZ on outer London without discussion, without the air quality justification of inner city areas, without enhancing within area transport, the scrappage offered is a joke compared to the cost of new vehicles, the lead time was totally inadequate.
So basically dumping a huge bill on a section of the public who are most hit by rising prices and interest rates over the past year.
Even those who can afford to buy new cars can't get them because long wait lists and escalating second hand prices.