Documentation: phases.txt
Complete guide to implementing and working with the General Traffic Signal Specification (GTSS).
phases.txt
phases.txt defines phases and the lane and movement type through the intersection, number of lanes, and links to an approach ID as defined in approaches.txt.
phase
phase is a unique identifier for each phase of a traffic signal. It is used to reference the phase in other GTSS files.
approach_id
approach_id is an ID number associated with a specific approach for each traffic signal. It is defined in approaches.txt.
signal_id
signal_id is a unique agency specific identifier for each traffic signal. It is used to reference the traffic signal in other GTSS files.
movement_type
movement_type describes the type of movement allowed during the phase, such as “L” for Left Turn, “T” for through. Additional Encodings shown in table below.
| Encoding | Phase Movement |
|---|---|
| T | Through |
| L | Left |
| LT | Left Through Shared Lane |
| TL | Permissive Left |
| LPP | Protected-Permissive Left |
| FYA | Flashing Yellow Arrow |
| U | U-Turn |
| R | Right Turn |
| TR | Through Right |
| PED | Pedestrian |
num_of_lanes
num_of_lanes indicates the number of lanes available at the stop bar for the movement during the phase.
pedX
pedX is an integer value indicating whether the defined phase includes a pedestrian phase and the approach it corresponds to as shown in the table below.
| PedX Integer | Meaning |
|---|---|
| 0 | No Crosswalk |
| 1 | One Crosswalk on the same approach as the phase assigned |
| 2 | Two Crosswalks show, one on the phase approach and one 180 degrees from the approach phase |
| 3 | One Crosswalk, 180 degrees from approach |
| 4 | One Diagonal Crosswalk |
| 5 | One Diagonal Crosswalk, 180 degrees from approach |
| 6 | 2 Diagonal Crosswalks |
| 7 | All Crosswalks in all Directions |
crosswalk_length
crosswalk_length provides estimated or actual distance values for pedestrian crosswalks. Refer to table below for types of estimation methods if available.
| Crosswalk_Length Encoding | Meaning |
|---|---|
| LE-# | Lane Estimated crosswalk distance (automatically calculated) |
| TE-# | Time Estimated crosswalk distance (if available, prefer to select the shorter of LE and TE) |
| # | Measured crosswalk distance in feet. This overrides lane and time estimated lengths |
Example
phase,approach_id,signal_id,movement_type,num_of_lanes,pedX,crosswalk_length
2,1,1,T,2,1,60