no there is no ghost as far as i am aware.
If you want to practice tracks do it offline, then you dont hurt anybody, you can toggle a racing line on/off with 1 of the keys, i cant remember which, but a racing line will clearly work as well as having a ghost.
It changes colour to show when to acc or brake or coast.
Very useful for someone who wants to learn a track, probably better than a ghost.
You can use racing line online too.
Only you will see it.