Using the phone is as safe as talking to a passanger
A lot of people claim that if you use a hands-free device for talking on the phone, you are as safe as when you are talking to a passenger. However, a passenger can actually see the road and usually stops the conversation when you are performing some more complicated manoeuvres. A person in a car can also notice any danger and inform the driver if he/she didn’t spot it. So it is much safer to speak with a passenger than being on a call, even if you don’t have to keep to phone with your hand.