When you're on the freeway/highway you mostly want a larger scale to see further ahead. On surface streets, generally you want more detail and don't need so see several miles ahead. What would be a great feature would be the ability to scale the map according to your speed/road type. Example, above 50 mph/75kmh zoom the map out a bit, and under 40 zoom the map in. Implementation would be a preference setting that could offer the ability to set scaling per individual tastes or turn it off.