A vehicle localization method comprising implementing, in a computer system the following steps: receiving a predetermined road map; receiving at least one road image for determining a vehicle location; processing, by a road detection component, the at least one road image, to identify therein road structure for matching with corresponding structure of the predetermined road map, and determine the vehicle location relative to the identified road structure; determining an approximate vehicle location on the predetermined road map and using the approximate vehicle location to determine a target area of the map containing a corresponding road structure for matching with the road structure identified in the at least one road image; and using the determined vehicle location relative to the identified road structure to determine a vehicle location on the road map, the vehicle location having a greater accuracy than the approximate vehicle location, by matching the road structure identified in the at least one road image with the corresponding road structure of the predetermined road map; wherein the road structure identified in the at least one road image comprises: a centre line for matching with a corresponding centre line of the road map, wherein determining the vehicle location relative thereto comprises determining a lateral separation between the vehicle and the centre line in a direction perpendicular to the centre line; and a junction region for matching with a corresponding junction region of the predetermined road map, wherein determining the vehicle location relative thereto comprises determining a longitudinal separation between the vehicle and the junction region in a direction along a road being travelled by the vehicle. receiving a predetermined road map; receiving at least one road image for determining a vehicle location; processing, by a road detection component, the at least one road image, to identify therein road structure for matching with corresponding structure of the predetermined road map, and determine the vehicle location relative to the identified road structure; determining an approximate vehicle location on the predetermined road map and using the approximate vehicle location to determine a target area of the map containing a corresponding road structure for matching with the road structure identified in the at least one road image; and using the determined vehicle location relative to the identified road structure to determine a vehicle location on the road map, the vehicle location having a greater accuracy than the approximate vehicle location, by matching the road structure identified in the at least one road image with the corresponding road structure of the predetermined road map; wherein the road structure identified in the at least one road image comprises: a centre line for matching with a corresponding centre line of the road map, wherein determining the vehicle location relative thereto comprises determining a lateral separation between the vehicle and the centre line in a direction perpendicular to the centre line; and a junction region for matching with a corresponding junction region of the predetermined road map, wherein determining the vehicle location relative thereto comprises determining a longitudinal separation between the vehicle and the junction region in a direction along a road being travelled by the vehicle. a centre line for matching with a corresponding centre line of the road map, wherein determining the vehicle location relative thereto comprises determining a lateral separation between the vehicle and the centre line in a direction perpendicular to the centre line; and a junction region for matching with a corresponding junction region of the predetermined road map, wherein determining the vehicle location relative thereto comprises determining a longitudinal separation between the vehicle and the junction region in a direction along a road being travelled by the vehicle.