One thing I really liked from my Volvo was the speed indicator showed three values in a very clever way.
- my actual speed
- my programmed speed
- and the speed of the vehicle in front of me
It was nice when approaching a slower vehicle to see just how much slower that vehicle is going. That info allows me to decide to switch lanes and pass or just ride along at that speed if it's only a little bit slower.
Ps-Volvo's GUI on this was pretty slick with three rings around the digital speedometer. It's wasn't a bunch of numbers but rather a visual guide. NO MATH needed.
Since Tesla has the ghosted cars, it would be cool to see the speed on each car. Just a thought.