That sounds like a terrible idea.
I already encounter plenty of people who, upon encountering an obstacle on their side of the road, will happily veer over into my side of the road, even if it means crossing a yellow(*) line. They don't seem to grasp that if they have an obstacle on their side, they should slow or stop instead of just veering into oncoming traffic like a moron.
If with a big strip down the center of the road which indicates "your side/my side" people will still cross into oncoming traffic, there is no way in hell I would trust them without the damned line. Hell, I routinely see places with two left turning lanes where half the drivers just stray into their neighbors lane like +- 15 feet is just fine.
Trusting the average driver I see to know where the middle of the road is without some form of guidance seems idiotic, because they can't do it now. I can't tell you how many people I see who seem to think they need 15 feet of space on their right to clear a parked car, which puts them firmly onto the side of oncoming traffic and are apparently too stupid to realize they can't do that.
As TFA says, "Absurd, barmy, crazy".
It's not a shared space, I get a lane, you get a lane, you stay the hell out of mine. You don't get to make use of my lane just because it's there and you don't know where your car is.
This sounds really really stupid.
(*) we use solid yellow lines to separate from on-coming traffic for you Brits, instead of dashed white ones -- white ones are to separate you from people going in the same direction.