High circular orbits move a lot slower than lower circular orbits (eg: geostationary orbits basically don't move at all relative to the ground). It's the highly elliptical orbits that have massive velocities.
FWIW, geostationary orbital velocity is like 3km per second.
I'm not sure that being stationary relative to the ground is very relevant since we are talking about stuff colliding in space. The more stable orbits seem like they might be less prone to issues, though.
