Can I compare like these ways?

I am twice as tall as you.
My height is twice more than yours.
= My height is as much as yours.
Smoking kills seven times more people each year than automobile accidents (kill).
automobile accidents.
-> Automobile accidents kill seven times as many people each year as smoking.


Are any of above sentences grammatically wrong?
Tell me please.
Thanks in advance.

I am twice as tall as you - correct, in common use.
My height is twice more than yours - would never be used by a native English speaker!

Neither of the above mean the same as ‘My height is as much as yours’ which is also not a sentence which would be used by a native English speaker.
I am the same height as you.’ would be the most common way of expressing being equal in height.

Smoking kills seven times more people each year than automobile accidents - correct (though ‘automobile’ is becoming quite an antiquated term. Most native speakers would say ‘road accidents’ or ‘road traffic accidents’.)
Automobile accidents kill seven times as many people each year as smoking. - correct (but does not mean the same as the above)

Smoking kills seven times more people each year than road accidents - correct
So, can I write like this: ‘Road accidents kills seven times less people each year than smoking.’ ?
Thanks again.

… kill seven times fewer people…