Signaling
A good driver always lets others know if he/she is going to turn or stop. Signaling communicates your intention when driving and
helps other drivers around you to plan ahead. A surprise move often results in a crash. Always be alert, watch for others, and give
signals for your movements.
Always signal when you are going to:
1. Change lanes
2. Make a turn
3. Pull away from a parking space parallel to the curb
4. Slow down or stop
5. Enter or leave a highway
6. Pull over to the side of the road
How to Signal
You may either use turn signal lights or hand and arm signals. If using hand signals, extend your hand and arm well out of the car window as shown below. Always make sure your signals can be easily seen by others, and signal in plenty of time.
Hand and arm signals are usually difficult to see during non-daylight hours, so it is important to make sure your signal lights are working properly.
When signaling a stop, pump your brakes a few times to attract attention.
Signal continuously for at least 100 feet before turning or stopping, and be sure to turn off your signal lights once your turn is complete.
Your unintended signal still means “turn” to other drivers.
http://www.dps.texas.gov/internetforms/Forms/DL-7.pdf <-Texas DPS handbook, Chapter 6, Page 42, September 2017 edition.
I personally have major irritation with drivers that think "oh, what's the harm"... and put their personal wants over the safety of everyone.