Every day bike riders and other road users put their lives on the line, literally, as we use the humble white line to guide and position us within the space on the road.
It's hard to imagine how a modern road transport system could function efficiently without those lines carving up the space and keeping us from harm.
But we do get practice. Increasingly the white is wearing off as maintenance is sacrificed for more glittering and politically appealing projects.
That’s somewhat OK for us because we use our experience and intelligence to guess where the white line should be, and act accordingly.
But what is a poor automated driving system to do?
Your car has lane keeping technology to keep it on the straight and narrow, and away from bikes in the bike lane, presumably; but what happens when the white line wears off.
The American Automobile Association has just conducted a major evaluation of active driving assistance systems and the findings are concerning.
It looked at a number of vehicles equipped with systems to assist the driver with acceleration , steering and braking, measuring what happened when they were driven on both test tracks and real world roads.
On fresh pavement (laid within the last six months) with well-defined lane markers, each evaluated system was able to maintain consistent lane positioning.
But there were many failures, with about 73 per cent of all the incidents in the study related to lane keeping: systems unexpectedly disengaging were of particular concern to the test drivers, who also found that there was little in the way of instrumentation to indicate when systems were engaged or not.
This seems to indicate that the claimed safety benefits of these systems, and eventually those of driverless cars, will be considerably dependent on white-line upkeep.
Which brings us back to bike riders. We know better than anybody just how poorly roads are maintained, just as we depend more than most on those lines for our fair share of the road.
If governments really are that keen on driverless cars, then first they better get white lines on the road that both humans and cars can make good use of.