Unless they took a very large sample this might not be entirely true. Or put differently the lane next to yours over a long time frame isn't moving faster, but

Unless they took a very large sample this might not be entirely true. Or put differently the lane next to yours over a long time frame isn't moving faster, but it does move faster at various points. By switching to the lane that is moving faster at that moment, you can move faster than your original does over the average.