They tend to be speed targets in many places, because if you drive under (or at) the speed limit in many places, you'll get hassled by aggressive drivers behind

They tend to be speed targets in many places, because if you drive under (or at) the speed limit in many places, you'll get hassled by aggressive drivers behind you, creating a more dangerous situation than if you sped up instead. (Based on my experience driving in the US, at least.)