http://www.nhtsa.gov/staticfiles/rulemaking/pdf/Distraction_NPFG-02162012.pdf
"The NHTSA Guidelines recommend that devices be designed so that tasks can be completed by the driver while driving with glances away from the roadway of 2 seconds or less and a cumulative time spent glancing away from the roadway of 12 seconds or less. "
We have been talking specifically about Waze and not at all about broader cell phone use.
I'll read that document in depth later. In the meantime, Waze is a cell phone app, is it not? Therefore, we're talking about the use of a cell phone while driving.