The primary function of this feature would be to create a transparent public record of drivers’ interactions with law enforcement, creating a database that could be used to improve accountability and reduce racial or other forms of bias by law enforcement.

Traffic stops are one of the most common forms of interaction with law enforcement in our daily lives. After a rash of recent deadly traffic stops involving African American victims of police violence, there is heightened attention to racial bias in traffic law enforcement. The problem is, academics and policymakers trying to identify racial bias often lack the data needed to draw conclusions and improve interactions with law enforcement. This feature would help address the lack of data and improve police accountability by providing a record of the driver’s interaction with the LEO from start to finish.

Here’s how it could work: immediately upon recognizing that you are being pulled over, you press an icon on the waze app that initiates the traffic-stop protocol. The app would show other users that a stop was underway (just as it already shows the location of speed traps), and use your phone‘s microphone (and possibly also camera) to record the entirety of your interaction. If/when a citation or arrest is made, the user could log the specifics of the interaction (including officer badge number, type of citation and amount of the fine) to create a transparent public record. Users could also enter notes about the interaction, including if there was any physical interaction, the manner of questioning, and the demeanor or attitude of the officer(s). (Other examples include: users could check a box or otherwise indicate whether the officer(s) requested a consent search of their vehicle, something researchers have pinpointed as a common form of racial bias).

The app could be developed in concert with academics who study traffic law enforcement (and also law enforcement agencies themselves). Any waze user could see the record of traffic stops on the waze website from a computer or tablet, and the information could also be furnished to academics, policymakers, and law enforcement itself.

This function fits well with waze’s mission to contribute to the 'common good' out there on the road. Anything that can help prevent senseless deaths at the hands of racist or prejudiced law enforcement would improve the common good.
References:

New York Times: “The Disproportionate Risk of Driving While Black” (front page, Oct. 25) http://www.nytimes.com/2015/10/25/us/racial-disparity-traffic-stops-driving-black.html