If you should slow down relative to the posted speed limit why not change the speed limit to reflect that directly?
Usually the reason is the "slow down" portion is very small, and it's confusing to shift down the actual speed limit for a 200 foot stretch of road then increase it again.
alt Hacker News
Usually the reason is the "slow down" portion is very small, and it's confusing to shift down the actual speed limit for a 200 foot stretch of road then increase it again.