The term expressway is currently used in Australia, Canada, China, India, Iran, Japan, Malaysia, New Zealand, Nigeria, Pakistan, Philippines, Poland, Qatar, Singapore, South Korea, Taiwan, Thailand, and the United States (where the term originated).
In the United States, an expressway is defined by the federal government’s Manual on Uniform Traffic Control Devices as a divided highway with partial control of access. In contrast, a freeway is defined as a divided highway with full control of access. The difference between partial and full access control is that expressways may have a limited number of driveways and at-grade intersections (thus making them a form of high-speed arterial road), while access to freeways is allowed only at grade-separated interchanges. Expressways under this definition do not conform to interstate highway standards (which ban practically all driveways and at-grade intersections) and are therefore usually numbered as state highways or U.S. highways.
This distinction was first developed in 1949 by the Special Committee on Nomenclature of what is now the American Association of State Highway and Transportation Officials (AASHTO). In turn, the definitions were incorporated into AASHTO's official standards book, the Manual on Uniform Traffic Control Devices, which would become the national standards book of the U.S. Department of Transportation under a 1966 federal statute. The same distinction has also been codified into the statutory law of seven states: California, Mississippi, Missouri, Nebraska, North Dakota, Ohio, and Wisconsin. However, each state codified the federal distinction slightly differently. California expressways do not necessarily have to be divided, though they must have at least partial access control. For both terms to apply, in Wisconsin, a divided highway must be at least four lanes wide; in Missouri, both terms apply only to divided highways at least 10 miles long that are not part of the Interstate Highway System. In North Dakota and Mississippi, an expressway may have "full or partial" access control and "generally" has grade separations at intersections; a freeway is then defined as an expressway with full access control. Ohio's statute is similar, but instead of the vague word "generally," it imposes a requirement that 50% of an expressway's intersections must be grade-separated for the term to apply.
However, many states around the Great Lakes region and along the Eastern Seaboard have refused to conform their terminology to the federal definition. The following states officially prefer the term expressway instead of freeway to describe what are technically freeways in federal parlance: Connecticut, Florida, Illinois, Indiana, Maryland, Massachusetts, New Jersey, New York, Pennsylvania, South Carolina, Virginia, and West Virginia. In those states, the term freeway is not in common usage and it is common to find Interstate highways which bear the name “expressway.” Minnesota officially uses "freeway" and "expressway" interchangeably (with both defined as what federal officials call freeways).
Most expressways under the federal definition have speed limits of 45-55 mph (70-90 km/h) in urban areas and 55-70 mph (90-110 km/h) in rural areas. Urban expressways are usually free of private driveways, but occasional exceptions include direct driveways to gas stations and shopping centers at major intersections (which would never be allowed on a true freeway).
A famous example of a local government getting into the expressway business is Santa Clara County in California, which deliberately built its own expressway system in the 1960s to supplement the freeway system then planned by Caltrans. Although the county planned to upgrade the expressways into full-fledged freeways, such a project became politically infeasible after the rise of the tax revolt movement in the mid-1970s.
In some parts of Canada, expressway is synonymous with freeway and is used to mean limited-access divided-highways with no at-grade intersections, with both terms used interchangeably. Examples include the Gardiner Expressway through downtown Toronto. Where the expressway turns into a 6-lane arterial road (Lake Shore Boulevard) east of the Don River, there is a sign warning of the end of the expressway. The Macdonald-Cartier Freeway is an example of a route that uses the freeway term.
The new Veterans Memorial Parkway in London, Ontario, has intersections instead of interchanges, thus the Parkway is not considered a freeway. The Parkway was designed to be a limited access highway for the city but the lack of funding for the highway forced it to be built with at-grade intersections. Other examples include the Hanlon Parkway in Guelph and Regional Road 420 in Niagara Falls.
In other locations, such as Alberta and most of Western Canada, an expressway is a high-speed arterial road along the lines of the California definition, while a freeway has no at-grade intersections.
In Quebec, the term freeway is never used, with the terms expressway (in English) and autoroute (in English and French) being preferred. English terms are rare, and only found on bilingual signage of expressways (abbreviated "expy") found in Montreal around bridges and on the Bonaventure Expressway; these signs are controlled by the federal government.
Expressway is used in the United Kingdom to describe the road network in Runcorn. The network is a controlled-access dual carriageway, similar in construction to a motorway, but designed to carry traffic around the town quickly and efficiently. Its design and construction were the result of experimental transportation ideas being tested during the New Town movement in the 1960s and 1970s.
The A38(M) in Birmingham is also known as the Aston Expressway.
The A814 in Glasgow is known as the Clydeside Expressway.
A road sign used in several European countries, showing the front of a car, indicates that a road allows only motorised vehicles able to achieve a high speed.
An expressway in Croatia (brza cesta, literally express way) is a road similar to a freeway, although it lacks the hard shoulder. Expressways are usually marked with letters B or D. They have much lower speed limits than motorways, usually . All expressways must have at least two lanes in each direction and all interchanges and exits must be grade separated. The longest such road in Croatia is B9, connecting Umag and Pula. All expressways are toll-free except for B8 and B9, parts of the Istrian Y network.