Crystal City, Texas, 1939

Alignment—the movement of a roadway through the landscape; its curves, straight sections and hills.

Arterial—a roadway providing the principal high-volume and high-speed linkages within a community and between communities.

Avenue—a broad urban thoroughfare, usually tree-lined.

Boulevard—a broad urban thoroughfare, usually tree-lined and with a broad median.

Clear zone—the recommended area alongside a roadway clear of all potential hazards (something an automobile might strike) such as trees, rocks, utility poles and the like. The recommended width of a clear zone varies based on the functional classification of the road.

Collector—a roadway providing service between arterials and local roads.

Designed landscape—a landscape, or the alteration or modification of the natural landscape, that has been created specifically to provide a desired experience (usually aesthetic) to the user or a community. Designed landscapes are generally created by a landscape architect, planner, architect or other design professional.

Design speed—the maximum safe speed at which a vehicle can be expected to operate on a roadway. The speed for which a roadway is designed—this may not be the posted speed.

Errant vehicle—a vehicle leaving the roadway in a reckless or uncontrolled manner.

Expectancy—a theory, based on a motorist’s “knowledge stores” of driving experiences, that suggests predictable driver responses to familiar situations and settings. Routine experiences, such as sufficient merging space at the end of a freeway ramp, become unconsciously established in the driver’s mind—thus creating conflict should the “expectancy” not be met.

Galvanized steel—a zinc coating applied to steel to prevent rusting. Galvanized steel has a flat chalky-gray appearance.

Guardrail—a barrier, usually of a post-and-beam construction located alongside a roadway, in medians and in front of hazards to prevent an errant vehicle from striking an obstacle or encountering a dangerous slope or drop-off.

Horizontal alignment—the movement of a roadway to the left or right; its curves.

Integrity—the current quality of a feature or element when compared to its original quality.

Jersey barrier—a angled concrete barrier designed to guide an errant vehicle back to the roadway and guard against hazards.

Lane—a narrow passage (or road) defined by buildings, hedges or fences.

Liability—an obligation to perform a specific duty.

Limited access—a concept whereby the entrances and exits of a roadway are restricted to certain locations—generally to allow for higher speed traffic movement due to the absence of cross streets and intersections.

Local road—a roadway serving adjacent residences and businesses—generally of low-volume traffic

Median—a central space, often planted, dividing opposite moving travel lanes.

National Register of Historic Places—a national listing of sites meeting the U.S. Secretary of the Interior’s standards, maintained by the National Park Service.

Neat line—an imaginary line representing the average face of an irregular surface, such as a stone wall.

Park road—a road through a park. A park road in an element within a park.

Parkway—a roadway contiguous with or linking park spaces. In its truest definition, a parkway provides access to recreational, scenic or leisure spaces.

Post and cable guardrail—a guardrail constructed of regularly spaced posts connected by a flexible (usually steel) cable.

Posted speed—the speed at which a roadway is signed. This is usually, thought not always, lower than the design speed.

Realignment—the repositioning of a segment of a roadway.

Reinforced concrete—concrete with a steel reinforcing framework. Reinforcing enables the concrete to perform in structural situations. Concrete by its nature resists high compressive loads (the heavy weight of a truck, for example). Steel reinforcing resists high-tensile loads (the pull to the left or right one would encounter on a bridge, for example).

Right-of-way—the land area dedicated to or associated with a roadway that is owned or managed by the road management entity—including the roadway, shoulder and affiliated landscape.

Shoulder—a stabilized level area adjacent and parallel to the roadway that provides a recovery space for an errant vehicle or a safe space for a disabled vehicle.

Sight distance—the length of roadway ahead that is visible to the motorist.

Standards—the legally adopted policies and practices directing the design and construction of a road.

Street—an urban thoroughfare, usually defined by buildings.

Superelevation—the banking or sloping of a road curve to enable vehicles to maintain a speed consistant with the overall speed of the roadway. The banked ends of racing tracks represent an exaggerated superelevation.

Taking—in legal terms, the direct acquisition of property, or the implementation of policies or actions that significantly impact a property.

Tort liability—a situation in which an injury or harm has occurred, due to a breach of a preexisting duty or obligation, resulting in potential exposure to an individual or organization for damages.

Vertical alignment—the movement of a roadway up and down; its hills.

Volume—the number of vehicles a roadway carries.

< top >