I'm trying to name a measurement that is measured in reciprocal length, which is in a draft document for vehicle risk management.
It currently says:
Crash rate = number of crashes / million kilometres driven
where the measurements are taken annually. So the units are in reciprocal length.
I'm not happy with the word "rate" because that seems to imply the number of events over time, whereas the measurement is the number of events over distance.
Existing names of units of reciprocal length in various disciplines don't seem to work - it's not a measurement of any cyclic phenomenon.
Is there an better word for this measurement?