 This type of road is not very standardized, and its geometry may vary from country to country or within a same country.These roads are usually, but not always, reserved for motorized vehicles, and accessible with limited-access roads (see ).Some European union regulation considers the high-quality roads are roads "which play an important role in long-distance freight and passenger traffic, integrate the main urban and economic centres, interconnect with other transport modes and link mountainous, remote, landlocked and peripheral NUTS 2 regions to central regions of the Union».