not real world enough
GPS and accurate maps are IMHO the wrong way to do it.
GPS can fail.
Maps get outdated
Not sure about US / Canada but in UK Motorway / Dual carriageway / restructure you can end up in extreme cases (lots of cones to separate things) using a lane of the "opposite direction" road. A car that throws a wobbly over roadwork induced changed topography is useless.
The only (IMHO) viable solution is car that can create its own internal image of the road layout (taking account of signs, cones, lights etc) - just like people do
.. and if they have to deal with some of the dubious lane markings / instructions on some UK roundabouts, give the AI the ability to cry / scream in frustration.
Their use of maps / GPS is because (as article states) the real time processing to build an internal model is too intensive currently - so wait until the tech is better then!
Still, all a long way off in UK as most of the work going on with US road systems.
A vehicle AI will only be any good when it seamless deals with moving from country a where they drive on left, signs in miles, to country B where they drive on the right, signs in km, lots of signage different e.g. UK person taking car on Eurostar / ferry to France