[dsfyu404ed]

What you're speaking of if pretty much analogous to driving at speed toward a light that just turned red the better part of a mile in the distance because you know (from experience, e.g. your commute) that in the time it takes to reach the light the light will change to green.

You're just making the location variable as well. This is a very common way of doing things for anyone that drives something that has horrible acceleration and a good view of traffic ahead (a typical forward control box truck full of stuff). When a temporary obstruction is noted up ahead, such as someone slowing for a right turn into a parking lot or it's easier to change lanes to go around the obstruction than it is to slow and speed up again. When changing lanes won't work, such as a bunch of cars that have yet to come up to speed after moving on a green light then slowing down slowly so that they're caught up to gradually is a viable alternative. Most people underestimate the amount they need to slow and wind up tapping the brakes at the end so fears of this causing unnecessary slowdowns are unwarranted IMO

Similarly, when encountering something like merging traffic on the right it's easier to maintain speed and move left to give the clusterfawk caused by the merging traffic space to run its course.

When driving a loaded truck the cost to slowing down is very high, these things have 0-60 times in the teens when unloaded and when traveling in traffic this is a pretty good incentive to avoid slowing down. The good view of traffic ahead allows drivers to adopt a strategy for driving at a consistent speed.