OAR 820-040-0030: Traffic Engineering

(1) "Traffic Engineering" is that branch of engineering which applies technology, science, and human factors to the planning, design, operations, and management of roads, streets, bikeways, highways, their networks, terminals, and abutting lands. Its objective is to provide for the safe, rapid comfortable, economical, convenient, and environmentally compatible movement of people, goods and services. Traffic engineering embraces studies and activities in connection with roads, streets, and highway traffic controls, which include signs, signals, lighting, pavement markings, and the following: (a) The planning, use, and design of traffic control devices and systems; (b) The use of algorithms for the operation of traffic control system; (c) The operational adjustment of traffic control devices and systems; (d) The preparation of traffic engineering reports; (e) The planning of traffic systems and networks, including environmental impacts, predictions of future needs, and interface with other modes of transportation; (f) Traffic related engineering economic feasibility studies; (g) The conduct of investigations and the preparation of recommendations relating to safety measures and improvements to be applied to highways including intersections, ramps, and railroad crossings; (h) Interrelationships of highways to other travel modes and abutting lands; (i) The operational and geometric design of roads, streets, bikeways, and highways. (2) Functional Areas: Four areas have been identified as functional classifications within traffic engineering. Each of the functional areas is further described as follows: (a) "Traffic operations" is the science of analysis, review, and application of traffic data systems, including accident and surveillance records, and volume and other data gathering techniques necessary for traffic planning. It includes the knowledge of operational characteristics of persons and vehicles to determine the need for installation of traffic control devices, and the treatment of the functional characteristics of the controls such as traffic signal timing. It includes the assessment of vehicular and human factors, their relationship with other traffic characteristics, the determination of safe transportation systems, and the need for inherently safe features and controls; (b) "Traffic design" consists of the design of traffic control devices and operational design. Traffic control device design includes those activities necessary to determine the appropriate and proper application of signs, pavement markings, signals, and signal systems, as well as to determine their location, and, if necessary, construction methods. It includes the preparation of plans, specifications, and estimates for the installation or modification of the various devices. Operational design concerns the visible features of a roadway. It may be thought of as the tailoring of the highway to the terrain, to the urban landscape, and to the requirements of the roadway user. It deals with such roadway elements as cross section, curvature, sight distance, channelization, and clearances, and thus depends directly on traffic flow characteristics; (c) "Traffic planning" includes the determination of travel pattern of persons and goods based upon engineering judgments derived from the study and analysis of traffic characteristics involving present, future, and potential land-use plans; and recommendations for transportation systems and networks of roadways. Traffic planning may include origin and destination studies; functional classification plans; travel forecasts; system, land or mode capacity studies; trip generation and distribution; modal split; traffic assignment; terminal and route location; and economic analysis. The prime responsibility of the traffic planner is to determine travel patterns and networks in concert with the several modes of transportation and their terminals; (d) "Traffic engineering research" includes the investigation of theoretical and applied aspects of all areas of traffic engineering for the purpose of developing new knowledge, new interpretations, and new applications. Traffic research may include hypothetical testing; impact studies; development of traffic hardware; theory formulation; methods of analysis, synthesis, and evaluation of existing phenomena and knowledge; and development of objectivity and thoroughness so that the validity of research findings can be demonstrated.