Blind pedestrians are around
Never
You would need to check local legislation. Different countries and states have differing regulations concerning the use of a vehicle horn.
Whenever someone is not paying attention while driving. If they are stopped at a green light or about to cause an accident, you should use your horn to tell them to stop what they are doing and pay attention. You should not use your horn to try and get the attention of someone outside of your vehicle. This can cause confusion and drivers around you to think that they are doing something wrong.
Never.
You are indeed allowed to. As long as you're not text messaging or holding your phone up to your ear, you're okay in many states.
Yes. Police should be allowed to use their mobiles. There is also the concept of the Defence of Duress or Defence of Circumstance, meaning they needed to break a law in order to protect life or prevent a more serious offence. They are allowed to use mobiles for policing only
No one should use cell phones while driving. Cell phone use while driving has been shown to cause as many accidents as drunk driving, even when hands-free devices are used. Texting while driving is even worse.
signaling your intentions
Not very different from texting while driving. If it isn't it should be.
no i do not and you are welcome
Answer: It is illegal to use a hand-hold cell phone while driving enywhere.
Yes. This the main reason why there are cell phone use laws while driving.