How should a lane change be carried out on a congested road?
A)By using the hard shoulder.
B)By performing the manoeuvre quickly so as not to cause obstruction.
C)By giving sufficient advance warning.Correct
By clearly warning other drivers and road users of the manoeuvre you intend to perform, with sufficient advance notice before beginning it, and using the vehicle's indicator lights as a general rule, or failing that, with your arm.