A high-hooded truck or SUV is far more dangerous to the public than a small car, and a small car is more dangerous than a motorcycle, so a speeding ticket/liscense points/jail time for an SUV should be >4x more severe than a motorcycle doing the same violation, and bicycles should basically only recieve token fines.
Visibility, mainly. Mass also, of course, in that it’s an important part of kinetic energy. Also the IQ trends of the (jacked-up dodge ram super-crew-cab long-box Extreme trim-package) driver.