There's a section on the freeway near work where they are doing... something (and really, at this point I don't even wonder what's going on any more), and apparently they needed more room at a few spots in the median.
So they took something that looked like this (fourth lane not shown):
And then they scraped the pavement to get rid of the paint in the section they wanted to change, which really means they made lane lines that are 1/4" into the asphalt instead of white paint sitting on top.
And then they painted the new lines, so you're driving forward and it looks about like this:
This is all happening at about 70 mph.
Some people notice the painted lines, other people go with the scraped-off asphalt as a guide, and a significant number of people just split the difference. It's a bit like watching bumper cars except I have yet to witness an actual accident here.
These are the days I wish my car was a lot smaller.