A park covering thousands of square kilometres can have queues at one viewpoint and no one at all a few valleys away. The distribution follows the road network with unusual precision.
Distance from the car decides everything
Visitor numbers fall steeply with walking distance from a parking area. The drop is sharpest in the first kilometre and continues from there.
By a few hours' walk, encounter rates are a small fraction of those at the trailhead, and beyond an overnight commitment they fall further again.
The consequence is that most of a large park receives almost no visitors while a thin strip along the roads absorbs nearly all of the traffic.
The road network was rarely designed for this
Many park roads follow routes laid out for logging, mining or early motoring, when visitor numbers were a fraction of today's and the vehicles were smaller.
They tend to run along valleys and lake shores, which are also the most productive habitat and the areas wildlife uses most heavily.
So the corridor carrying the pressure often overlaps the ground that would benefit most from being left alone, which is a legacy problem rather than a planning choice.
Corridor effects extend beyond the tarmac
Traffic noise carries far enough to change how animals communicate and forage, and the affected band is considerably wider than the road itself.
Roads also act as barriers, with some species reluctant to cross open surfaces, which fragments habitat along the whole length rather than at a point.
Vehicle collisions concentrate at specific spots where animal movement crosses the route, and those spots are stable enough to be mapped and mitigated.
Managers use the concentration deliberately
Because pressure is predictable, it can be hardened. Surfaced viewpoints, boardwalks, robust toilets and defined parking absorb heavy use in a small area.
Concentrating impact on ground already committed is generally preferable to dispersing visitors thinly across sensitive terrain, where the total damage would be greater.
This is why parks build facilities at busy points rather than trying to redirect people elsewhere. The corridor is functioning as a sacrifice zone by design.
Shuttles change the arithmetic
Replacing private vehicles with shuttles removes the parking constraint, cuts the paved area required and allows one-way walks that a car-based visit cannot support.
It also decouples arrival from parking availability, which is what timed entry systems are otherwise trying to solve.
For a visitor, the practical lesson is that a modest walk changes the experience of a park more than choosing a different park does.