I highly doubt this is still the case considering auto manufacturers far behind the curve on this tech [1] are doing things like recognizing stop signs and reading speed limit signs using on-board cameras. Lane keeping also uses onboard sensors. As far as I know, the most important thing high-resolution maps are needed for is decision-making for things more than a few hundred feet ahead (ex. when to get in the right lane to exit or turn). It also helps with driving in adverse conditions where it's difficult to use normal sensors to see road markings. There are plenty of players working on this, though, so I don't think it's a huge obstacle. For example, [2].

[1] https://en.wikipedia.org/wiki/Traffic_sign_recognition [2] http://blog.caranddriver.com/how-high-definition-maps-are-pl...