| Word |
Description |
| L (L) |
The symbol used for inductance or change in inductance. |
| Lead-In Cable |
The electrical cable which serves to connect the lead-in wire in the pull box to the input of the loop detector unit in the controller cabinet (NEMA). Sometimes called "home-run" cable or transmission line. |
| Lead-In Wire |
That portion of the loop wire that is between the physical edge of the loop and the pull box which should be twisted a specific number of times per foot. For a magnetic detector or magnetometer, it is the wire which runs fro the sensor (probe) to the pull box. |
| Light-Sensitive Dectector |
A detector consisting of a light source and photoelectric cell(s), capable of being operated by the passage of an object (e.g. vehicle, pedestrian, animal..) interrupting the beam or beams of light. When properly equipped, directional characteristics are present. |
| Limited Presence Mode |
Detector output continues for a limited period of time if vehicles remain in the field of influence. See Detector Mode. |
| LIP |
See Local Intersection Program (LIP) |
| Local Intersection Program (LIP) |
Type 170 software program developed by Caltrans which incorporated detector timing features within the program. |
| Locking Detection Memory |
A selectable feature of the circuit design for a controller phase whereby the call of a vehicle arriving on the red (yellow) is remembered or held by the controller after the vehicle leaves the detection area until it has been satisfied by the display of a green interval to that phase. |
| Loop Detector |
A detector that senses a change in inductance of its inductive loop sensor caused by the passage of presence of a vehicle near the sensor (NEMA). See also Loop Detector System. |
| Loop Detector System |
A vehicle detector that senses a decrease in inductance of its sensor loop(s) during the passage or presence of a vehicle in the zone of detection of the sensor loop(s) (NEMA). A system would also include the loop wire as well as the electronics package. |
| Loop Detector Unit |
An electronic device which is capable of energizing the senor loop(s), of monitoring the sensor loop(s) inductance, and of responding to a predetermined decrease in inductance with an output which indicates that passage or presence of vehicles in the zone of detection (NEMA).
It is the electronics package, exclusive of the loop wire(s) and lead-in cable. |
| Loop Lead-In Wire |
The portion of the loop wire that is not part of the loop but is in the saw slot connecting the loop to the edge of the roadway, where it is carried in conduit to the controller or else to a pull box, where it is connected to the lead-in cable. |
| Loop Occupancy Control |
A detector/controller design using long detection loop(s) (normally 30 ft (9 m) or longer), and a controller unit operated in the non-locking mode.
Loop occupancy control can utilize magnetometer detectors as well as loop detectors. |
| Loop System |
A combination of loop wire connected through lead-in cable to the detector in-put terminals. |
| LSI Chip |
An electrical component with more than 1,000 logic elements. This is "large scale integration" of miniature elements and is used in some loop detector units of digital design. |
| LTPP |
Long Term Pavement Performance |
