From the programme, it sounds like they mean shutting down most of the CBD to non-essential travel on a regular periodic basis. Like once a week or once a month or something. So deliveries and such would probably still happen, and obviously so would emergency vehicles, but the average person wouldn't be allowed to drive in.

in a world where many many people struggle with mobility, there needs to be some form of semi-direct access

The thing is, a car-dependent world makes this worse for people, not better. It makes it hard to get places if you can't drive, whether that's because of a disability, an inability to afford the high prices, or because you've been excluded from driving, or, as a close family friend is currently going through, simply because of age and the physical & mental effects of aging.

Aside from the periodic changes, one of the best things we could do would be to permanently turn our CBDs into pedestrianised zones. Places where drivers are entirely allowed to go if they want, but where they have to expect to be driving very slowly because pedestrians get complete right of way. Here in Brisbane we already have this in a few places, like along Albert St between Adelaide St and Burnett Ln. As well as Burnett Ln itself. Extending that to almost the entire CBD (minus one or two key roads used by public transport—such as Brisbane's Adelaide St) would be a massive boon for safety and comfort, without impeding the ability for people who still choose to drive to be able to.

Also, be better, ABC

Strong agree. A text transcription would be great, and personally I'd love it if they allowed you to play back audio at 2x speed because their presenters all speak so slowly.