When changing lanes or turning you are supposed to use the turning signal before doing the manouver. The turning signal is supposed to warn other drivers that you are going to do something. It doesn’t make any sense to use the turning signal when already mid-turning or while already changing lanes. Many drivers don’t seem to know that.
My current car was even built around that stupid idea that turn signals are for while you change lanes.
It has a feature called “blind spot safety”. Basically if I’m on the interstate and I put on my blinker to let people know I want to change lanes, if there’s a car in the left lane it turns down the music and beeps a loud warning at me.
In other words, it treats me turning on the turn signal, when the lane on that side isn’t clear, as a danger scenario deserving of a warning. It’s the same kind of warning as the collision warning.
So basically, it’s built on the assumption that me turning on my turn signal means I’m already turning the wheel to go there.
Beeping at you makes sense though, because often you already know the lane is clear when you hit the turn signal, just by paying attention while you’re driving.
I click it and check the blind spots, then proceed. If I somehow missed something in my blind spot, I think it would be nice to know.
Also the lane must be clear before you switch lanes. It is not necessary for the lane to be clear before you signal.
Your comment is also written from the frame that signaling equals changing lanes.
I turn on my turn signal to request a space to move into the packed lane. I don’t go into the lane until someone has seen the signal and is holding a space for me.
The turn signal is a communication device. That communication would be nearly useless if it were only used when nobody was in the lane you were going to. It’s the people in the lane you’re targeting who are the primary recipients of that message.