Oil prices are so high that CO2 emissions from fossil fuels are dropping
(www.scientificamerican.com)
It honestly depends on a huge multitude of factors. ACV is one of them, but a low cost generally means a lower rate. Collision is almost always more expensive than comp.
Collision: anything you hit while moving (another car, a pedestrian, a tree, a pole, an adnominal in the road) <--things that would otherwise be avoidable.
Comprehensive: "Act of God" stuff (lightning strike, tree limb falls on it, theft, an animal actively jumping out in front of you, hail damage) <--not likely to affect your rates for claims since it's near unavoidable.
If a truck blew out a tire and it rolls into your lane and you hit it: comprehensive. If the tire blows out and other cars swerve to miss it laying there, but you hit it: collision.