Tbf they should do this in London too. They're looking to pedestrianise Oxford Street, but who knows when that will happen as we need to allow plenty of time for the government to find the right contractors to shovel money at for a project delivered overtime and underbudget.
A lot of it over here is for show, like ULEZ where huge range rovers are somehow exempt. Or where LTNs are always put on the richest streets in the nicest neighborhoods for reasons of "think of the wee children playing in the street" when there are plenty of children living outside of LTNs. Just a coincidence that all the properties inside an LTN are worth >£850k.