An autovía is one of two classes of major highway in the Spanish road system similar to a British motorway or an American freeway. It is akin to the autopista, the other major highway class, but has fewer features and is never a toll road. Some distinguishing features of an autovía are that it must be divided by a median, it must have restricted access, and it cannot be crossed by other roads. While autopistas are generally new routes, autovías are normally improvements to existing roads, so they may have tighter curves and less safe accesses, often with shorter acceleration lanes. However, both have nominal speed limits of 120 kilometres per hour (75 mph). Rest areas are usually 300 kilometres (190 mi) or 2 hours apart. There is usually a safety lane along the median.