The route I take to get my daughter to dance class is frequently traveled. It also has some speed limit changes as the areas it traverses change. On the Baltimore County side, when it's Nicodemus Rd, it's 30 mph. When it crosses into Carroll Co and becomes Deer Park Rd it's in the reservoir and the speed limit goes to 45 mph. Once the reservoir ends and there are some sporadic residences, the speed drops to 40 mph, though that's newly dropped from 45 mph.
Anyway, far too many people drive the same speed on the road, regardless of the speed limit. Sometimes I'm stuck behind someone who was driving well over 40 mph in the 30 mph zone, but doesn't pick up to 55 mph for the 45 mph zone. Other times I'll have one of them come flying up behind me in the 30 mph zone, only to leave them behind when I hit the 45 mph zone. Then I may get them back in the 40 mph zone.
Look, people, the speed limit changes on roads for good reason. It's not random. Conditions have changed. On the Baltimore County side, housing is more dense, as is the frequency of side streets, even though it's zoned rural. Slow down. It's not the highway, or even Reisterstown Rd. But in the reservoir there's nothing. Pick up the pace.
These lessons apply to other roads, too. It's a good rule of thumb that you can safely drive 10 mph over the posted speed. Cops tend to leave you alone, too. Hell, even the speed cameras won't hit you until you hit 12 mph over the posted speed. So, keep it to 10 mph over the posted speed, and you'll get there safe, sound and timely, with no delays for a speeding ticket.