In other developed countries, greater standardization of road signs and markings makes it easier for robot cars to navigate. In the U.S., however, traffic lights can be aligned vertically, horizontally or "dog-house" style in two columns. Pavement markings use paint with different degrees of reflectivity - or don't exist at all.Perhaps the simplest fix is to build rails for driverless trams. Looks like Honolulu are working on something more advanced than the O'Hare people mover but not quite as ambitious as the Lindenwold High Speed Line.
"If the lane fades, all hell breaks loose," said Christoph Mertz, a research scientist at Carnegie Mellon University. "But cars have to handle these weird circumstances and have three different ways of doing things in case one fails."
INSTEAD OF DRIVERLESS CARS.
The sensors still aren't good enough to stay on a distressed road. And local control of road markings and such causes challenges.