Another suggestion would be when the app sees there is heavy traffic well before and notifies the driver of different routes available due to the accident or whatever may be holding up traffic.

Currently, when there is an alert given "amount of time in traffic, x minutes." once you're already in the traffic. It would be nice if that alert was given sooner AND provide the opportunity to re-route. For example, "traffic ahead will add x minutes to your trip. Would you like to re-route around the traffic?"

when a route is not entered into waze , and your on a highway or parkway and there is traffic ahead alert the driver of upcoming traffic

I would add a loop that answers the following conditions

while (trafficAhead is <= (.33 * myCurrentSpeed) //maybe .5?
&&

trafficAheadIsOnSameRouteAsMine = true //so that it doesn't warn us for people on off-ramps, etc..
&&

trafficAhead >= 4 cars //so that it doesn't consider cars stopped on the shoulder as heavy traffic...
{
if (myLocation <= (trafficAhead - 1km) //give the warning when we're a kilometer away
{

Announce("Slow down. Heavy traffic ahead.")
}
}

When driving on a freeway The GPS should say look there’s traffic ahead Time to slow down