I think it would be helpful if Waze would generate a warning when you enter a highway on which no wazer passed in the last 1-2 hours. Otherwise you count on the fact that if there is any Police on that highway you would receive a warning from Waze but since no wazer passed through that area lately you have actually no info related to that road (and you are not aware of that).
Such a warning would force you to drive more careful and avoid speed tickets.