Traffic is rarely “free flowing” at any speed on these kinds of roads. Often I see “moving roadblocks”: clumps of cars going around or just under the speed limit jockeying around each other, impeding other traffic from moving around them. So-called “defensive drivers” are often unpredictably overly cautious: I’d wager they are at least an indirect cause of accidents quite often, but are severely under-represented in the statistics (if/when they’re represented at all).