Thanks John for the reminders, I know I can use them.

As a relatively new driver I was taught, and continue to use the raised arm to indicate to the cars behind me that I am suddenly slowing. Whether this is for a yellow flag, waving or standing, that I have observed, or a mechanical condition of my car. Am I wrong to do so?
For me, it is good common sense and I have had other drivers do the same as I approach them. It is different than a point by and easily understood by the following car if they see the raised hand.

FWIW I had 6 lanes of interstate lit up by brake lights Tuesday afternoon as people dropped from 75+ to dead stop for a tractor trailer on fire on the median wall. Not only did I check my mirrors and leave myself an escape path I realized, after coming to a stop, I had raised my hand to alert the drivers behind me. I feel much safer on track than with the idiots I normally commute with.

Paul