When driving in fog, darkness or on unfamiliar roads I want a warning from Waze, if my speed is greater than (say) the 90th percentile of the Wazer statistical distribution for my position and driving direction.

I would also like to be alerted if another Wazer near before me drives much slower than I do.

BACKGROUND

Guidelines from location- and real-time data on the speed of Wazers should be more safety-relevant than rigidly posted speed limits, constant over both time and long distances.

=== Police Supervision of Posted Speed Limits Obsolete ===

Such functions in Waze may contribute considerably to driving safety. In the long run they will hopefully also put an end to the non-scientific police and camera speed supervision.

Today's punishment of individuals missing a speed sign is hardly significant to safety in normal situations. Through GPS navigators' and drivers' common warnings of police presence, this unfortunate focus on posted speed limits also reduces police efficiency when chasing real criminals.

Research indicates that a great speed deviation from that of the average traffic flow is more dangerous than a minor violation of the posted speed limit. This is the case also for unusually low speeds.

=== Regression fallacy ===

Speed cameras have been justified with false claims on their alleged accident reduction. Such overestimations of the safety influence (from reduced local traffic speed and from lowering speed limits as well as from speed cameras) are based on ignorance of the statistical regression effect: http://en.wikipedia.org/wiki/Regression_fallacy

Decades ago the same misconception gave exaggerated cause for traffic lights.