ETA on Route Advisor Inaccurate?

[n4gix]

Never liked Garmin I have only used devices based on WinCE, on which I can install my own software (usually iGo). Regarding the estimation based on current speed, what happens if you stop at a traffic light?

According to the manufacturer, the ETA calculation is based on the last three minute average speed, and stops averaging when speed is zero. Hence, the ETA remains the same even when stopped, but is then recalculated as soon as the car is moving again.