Except the potential issue is that while R to T is the worst spot according to the data, there is a route in a poorer neighbourhood, C to F, that is far worse a

Except the potential issue is that while R to T is the worst spot according to the data, there is a route in a poorer neighbourhood, C to F, that is far worse and more deserving of improvement than R to T. And it may be hard to know in practice whether this effect is happening or not.