|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

|  | G08 |
SIGNALLING (indicating or display devices per se Fulltext... Hierarchy... Expanded...G09F; transmission of pictures Fulltext... Hierarchy... Expanded...H04N)

|  | G08G |
TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic Fulltext... Hierarchy... Expanded...B61L; arrangement of road signs or traffic signals Fulltext... Hierarchy... Expanded...E01F 9/00; radar systems or analogous systems, designed for traffic control Fulltext... Hierarchy... Expanded...G01S 13/91; sonar or lidar systems specially designed for traffic control Fulltext... Hierarchy... Expanded...G01S 15/88, Fulltext... Hierarchy... Expanded...G01S 17/88) [2]

|  | G08G |
Note(s) This subclass covers: identification of traffic offenders; indication of the position of vehicles; indication of free spaces in parking areas.

|  | G08G 1/00 |
Traffic control systems for road vehicles

|  | G08G 1/005 |
· | including pedestrian guidance indicator [5]

|  | G08G 1/01 |
· | Detecting movement of traffic to be counted or controlled (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G08G 1/07-G08G 1/14 take precedence)

|  | G08G 1/015 |
· · | with provision for distinguishing between motor cars and cycles

|  | G08G 1/017 |
· · | identifying vehicles (Fulltext... Hierarchy... Expanded...G08G 1/015, Fulltext... Hierarchy... Expanded...G08G 1/054 take precedence) [5]

|  | G08G 1/02 |
· · | using treadles built into the road (pads or other sensitive devices responsive to passage of vehicles Fulltext... Hierarchy... Expanded...E01F 11/00)

|  | G08G 1/04 |
· · | using optical or ultrasonic detectors

|  | G08G 1/042 |
· · | using inductive or magnetic detectors [5]

|  | G08G 1/048 |
· · | with provision for compensation of environmental or other condition, e.g. snow, vehicle stopped at detector [5]

|  | G08G 1/052 |
· · | with provision for determining speed or overspeed [5]

|  | G08G 1/054 |
· · · | photographing overspeeding vehicles [5]

|  | G08G 1/056 |
· · | with provision for distinguishing direction of travel [5]

|  | G08G 1/065 |
· | by counting the vehicles in a section of the road or in a parking area, i.e. comparing incoming count with outgoing count

|  | G08G 1/07 |
· | Controlling traffic signals

|  | G08G 1/08 |
· · | according to detected number or speed of vehicles

|  | G08G 1/081 |
· · | Plural intersections under common control [5]

|  | G08G 1/082 |
· · · | Controlling the time between beginning of the same phase of a cycle at adjacent intersections [5]

|  | G08G 1/083 |
· · · | Controlling the allocation of time between phases of a cycle [5]

|  | G08G 1/085 |
· · | using a free-running cyclic timer

|  | G08G 1/087 |
· · | Override of traffic control, e.g. by signal transmitted by an emergency vehicle [5]

|  | G08G 1/09 |
· | Arrangements for giving variable traffic instructions (indicating arrangements for variable information by selection or combination of individual elements Fulltext... Hierarchy... Expanded...G09F 9/00)

|  | G08G 1/095 |
· · | Traffic lights

|  | G08G 1/0955 |
· · · | transportable [5]

|  | G08G 1/096 |
· · | provided with indicators in which a mark progresses showing the time elapsed, e.g. of green phase

|  | G08G 1/0962 |
· · | Indicator mounted within vehicle [5]

|  | G08G 1/0965 |
· · · | responding to signals from another vehicle, e.g. emergency vehicle [5]

|  | G08G 1/0967 |
· · · | Highway information, e.g. weather, speed limit (navigation systems Fulltext... Hierarchy... Expanded...G08G 1/0968) [5]

|  | G08G 1/0968 |
· · · | Navigation systems [5]

|  | G08G 1/0969 |
· · · · | having a display in the form of a map [5]

|  | G08G 1/097 |
· | Supervising of traffic control systems, e.g. by giving an alarm if two crossing streets have green light simultaneously

|  | G08G 1/123 |
· | indicating the position of vehicles, e.g. scheduled vehicles (navigation systems Fulltext... Hierarchy... Expanded...G08G 1/0968) [5]

|  | G08G 1/127 |
· · | to a central station [5]

|  | G08G 1/13 |
· · · | the indicator being in the form of a map [5]

|  | G08G 1/133 |
· · | within the vehicle [5]

|  | G08G 1/137 |
· · · | the indicator being in the form of a map [5]

|  | G08G 1/14 |
· | indicating individual free spaces in parking areas

|  | G08G 1/16 |
· | Anti-collision systems [2]

|  | G08G 3/00 |
Traffic control systems for marine craft (marking of navigational route Fulltext... Hierarchy... Expanded...B63B 22/16, Fulltext... Hierarchy... Expanded...B63B 51/00)

|  | G08G 3/02 |
· | Anti-collision systems

|  | G08G 5/00 |
Traffic control systems for aircraft [2]

|  | G08G 5/02 |
· | Automatic landing aids, i.e. systems in which flight data of incoming planes are processed to provide landing data (landing aids fitted in or to aircraft Fulltext... Hierarchy... Expanded...B64D 45/04; visual or acoustic landing aids Fulltext... Hierarchy... Expanded...B64F 1/18)

|  | G08G 5/04 |
· | Anti-collision systems

|  | G08G 5/06 |
· | for control when on the ground [2]

|  | G08G 7/00 |
Traffic control systems for simultaneous control of two or more different kinds of craft [2]

|  | G08G 7/02 |
· | Anti-collision systems [2]

|  | G08G 9/00 |
Traffic control systems for craft where the kind of craft is irrelevant or unspecified [2]

|  | G08G 9/02 |
· | Anti-collision systems [2]