My Mother had just gotten a Prius, and she loves hers as much as we love ours.
They are very comfortable cars, but the seatbelts tend to rub against our necks.
It could be because we are short, but whatever the reason, a homemade cover is very soft and works great.

This pattern uses a linked-double-crochet and a chain-loop-fringe.
The pattern is fairly easy and the fringe is very soft on the neck.
There is a snag-free-Velcro closure, which makes it easy to put on and take off.
And using a cotton yarn, makes it machine washable.

As always, this is another free pattern.
I hope you enjoy it!
Pan