The US state of Maryland has introduced a law banning the use of handheld phones while driving.

The law requires drivers to use a hands-free headset to make or receive calls, with fines starting at $40 for a first offence and rising to $100 for each subsequent violation.

The law has also been introduced in the states of California, Connecticut, Delaware, New Jersey, New York, Oregon, Utah and Washington.

Maryland is one of 30 US states where it is illegal to send or receive text messages while driving.