Victor airways

In the United States and Canada, Victor airways are low-altitude airways. They are defined in straight-line segments, each of which is based on a straight line between either two VHF omnidirectional range stations, or a VOR and a VOR intersection, hence the beginning letter V.

United States

In the United States, Victor airways are designated by the FAA in FAA Order JO 7400.11. They are available for flight up to, but not including, 18,000ft MSL under either instrument flight rules or visual flight rules.
Victor airways have minimum altitudes for IFR operations established. For VFR operations, victor airways are just a subset of so-called Federal airways, which are designated as Class E, and hence are extended from above ground level (AGL) up to, but not including, above mean sea level (AMSL).
Victor airways are depicted as black solid lines on IFR Low-Altitude Enroute charts and as thick faded blue lines on VFR Terminal and Sectional Area charts. They are identified by a number, similar to an interstate highway.
The width of the victor corridor depends on the distance from the navigational aids :

When VORs are less than 102 nautical miles from each other, the airway extends 4 NM on either side of the centerline.
When VORs are more than 102 NM from each other, the width of the airway in the middle increases to account for the increased margin of error in the VOR signal. The width of the airway beyond 51 NM from a navaid is 4.5 degrees on either side of the centerline . The maximum width of the airway is at a designated changeover point between the two navaids, usually half way.

Canada

Controlled low-level airways extend upwards from 2,200 ft AGL up to, but not including 18,000 ft ASL.

VHF/UHF airways

The basic VHF/UHF airway width is at least 4 NM on each side of the centerline prescribed for such an airway, and is expanded along a line diverging 4.5° on each side of the centerline from the designated facility.

LF/MF airways

The basic LF/MF airway width is at least 4.34 NM on each side of the centerline prescribed for such an airway, and is expanded along a line diverging 5° on each side of the centerline from the designated facility.

Mixed airways

Where a Victor airway is established based on a VOR/VORTAC and NDB, the boundaries of that airway will be those of an LF/MF airway.

T-routes

Low-level controlled fixed RNAV routes have dimensions of 4 NM of primary obstacle protection area, plus 2 NM of secondary obstacle protection area on each side of the centreline. The airspace associated with RNAV T-routes is 10 NM on each side of the centreline. RNAV T-route airspace and protection areas do not splay with distance from the waypoint.