I think the last statement of the parent is causing the confusion. >On average now 67% of the time the other line will move faster. This should be: "On averag

I think the last statement of the parent is causing the confusion. >On average now 67% of the time the other line will move faster. This should be: "On average, you spend 67%~ of your time in the slower lane." On average the other lane is still only faster 50% of the time assuming the odds are truly 50/50 - but you spend 67% more time in the slower lane.