The remaining time is likely to be spent at the operator's depot doing any number of things. And whilst on-site, they will be expected to wear that staple clothing item of the bus industry - the high vis jacket. Pretty standard, and pretty obvious why it's required. There's no point in being run over by several tonnes of metal in the workplace if you can avoid it.
But on the bus, it now seems commonplace for drivers to hang said jacket either on the back of their seat or against their window - making something that was designed to be highly visible in a depot, just as highly visible to a potential customer.
So, the two things any passer-by would see at a quick glance of their local service would be the driver, and a certain colourful jacket taking pride of place at their side. And while it might be logistically the easier choice for a driver to take it on their shift, I don't think it does wonders for the image of bus travel in general.
If we're comparing bus travel with the world of retail, I can't think of any high street brands that allow their customer-facing staff to show off clothing more suited to moving stock around the warehouse. Doesn't help sales, doesn't help the brand's image.
I'm sure the problem is something bus bosses are aware of, so why do drivers keep doing it? I doubt they're all ignoring instructions from above.
Having a jacket on show in the cab certainly isn't the end of the world but all these little things add up in the minds of potential customers.
So, if in doubt, chuck it on the floor where nobody can see it!