I have made a lot of suggestions in Facebook, itunes, but waze developers seem to aim to other kind of improvements.

It could be very useful if Waze becomes an app with everything you need while Driving / Navigating.
so a feature I have been thinking is in showing the speed in the last 5 minutes or the differents speeds during a travel.
( why? sometimes policeman in Colombia wants to ticket you because they think you drive too fast )

I discovered that this feauture already exists in another app in itunes, an app called speedometer, an its free, but why using different apps when you can join everything like in waze

as a systems engineer i know adding this feauture is very easy because waze already haves a speedometer, now they just have to add persistence to add the spped at any time to a graphic where the x-axis is time and y-axis is speed.