The marvellous new concept in highway engineering circles is the Shared Space, which is pretty much the new name for 'road' except that it has less stuff like barriers, kerbs, bollards, signs and lights to keep cars from crashing into obstacles like cycles and pedestrians. The idea being that if you introduce uncertainty as to who belongs where in the road, drivers are less clear of their entitlement and more likely to give the road their full attention and other road users more consideration. The old certainties on which we could rely, when men were men, and a pedestrian's place was on the pavement, are being consigned to history and replacing them is a confusing new cross-dressing order where anyone can randomly wander around the street at will.
At War With the Motorist has pointed out that Shared Space is pretty much an admission of failure. All the traffic control and engineering innovations of the past 50 years are being declared obsolete and swept away.
It's interesting to think that there are spaces shared between cycles and pedestrians at the moment, such as London's South Bank, which the authorities want to - erm - unshare. There's also spaces shared between cycles and cars (the technical term is 'roads'), which are the reason many people think cycling on roads is 'too dangerous'.
Sharing is a great concept, but it presupposes that the parties sharing are more or less equal in power, and there isn't one group of bullies in the playground that are so much bigger and tougher than the other kids that they are able to intimdate their way to the lion's share of what's on offer.
The reason pavements work is everyone is of more or less equal strength and weight, and each individual is usually not capable of inflicting much damage on another (at least, unintentionally). Because of this, there's a protocol that's respected by almost all pedestrians, except on a Friday or Saturday night.
As soon as you introduce cars into the shared space, the dynamic changes. Even if most drivers act with care and consideration, it only takes one or two before pedestrians are anxiously looking about, grabbing their childrens' hands and scurrying to the side the every time they hear a car engine. So you get a 'scared space', not a 'shared space'.
However, it does appear that shared spaces have a better collision record than normal roads. Why? Maybe it's a reflection of how badly-designed roads have become, rather than 'shared spaces' being ideal. Roads have become places where the presumption of right of way heavily favours the driver, and the consequences of collisions are distributed almost exclusively onto the most vulnerable road users.
I'm going to suggest that shared space is actually a nonsense concept. It's used to justify spending a fortune on York stone slabs, granite setts, and generally digging up the road and giving it a makeover to keep highway engineers in a job. All you really need to do is get rid of the traffic. This is borne out by the DfT Shared Space Project Appraisal, which says "The willingness of pedestrians to use a Shared Space as intended depends on a combination of vehicular speed and flow and possibly on the relative flow of pedestrians to vehicles. The more favourable the conditions, the greater the tendency for pedestrians to occupy the space ...the percentage of pedestrians walking along the road reduced as vehicle flow increased. This study also found that the most influential factor on pedestrians’ willingness to walk in the road was the speed of motor vehicles...Many Shared Space schemes aim to increase the space available to pedestrians...The extent to which this is successful varies with the flow, and most particularly speed, of motorised traffic."
You got that? Vehicular speed and flow? So to create a space that pedestrians will use, what you need to do is get rid of the traffic. The rest is just gravy.