Ms Baker’s letter also raised the issue of car clubs, saying they should be treated differently from private electric cars.
She wrote: “Car clubs are a key tool to reduce need for car ownership and, as a result, reduce car journeys.
“Congestion charge policies should support car clubs as a tool to reduce unnecessary journeys and support a transition to cleaner vehicles.”
Car clubs are short-term car rental services which allow members to use locally-parked cars for individual journeys, meaning they can give up their cars whilst allowing for occasional car travel.
She said the current proposals risked making it more difficult for these clubs to operate.