Appendix E 5.1 Provision of Signal Hardware and Location
Following the signal timing and performance analyses in the previous sections, the intersection geometry and phasing design can be finalised, and the necessary signal hardware such as signal faces, posts, mast arms, controller and detectors, as well as the line markings and signposting, may be included on the base plan of Design 2. For detailed information, see Part 10 of the Guide to Traffic Management (Austroads 2019d) for the use and location of this equipment, Section 6.8 for the basic logic and installation of detectors, and Part 10 of the Guide to Traffic Management (Austroads 2019d) for various types of pavement marking and signposting.
Figure E 13 shows the line marking, signal face locations and provision of some accessories. The following discussions are based on this figure.
Since the movements on the east, south and west approaches do not include any arrow‑controlled turning movements; the basic three-aspect signal display is used. However, as the signal faces for the north approach are required to provide for a leading right turn phase, a six-aspect multicolumn signal face is used. This consists of a column of three-aspect (green, yellow and red) right turn arrows in addition to the basic three-aspect signals (Part 10 of the Guide to Traffic Management, Austroads 2019d). This operation could also be implemented using a five‑aspect two‑column signal face with green and yellow right turn arrows only (Part 10 of the Guide to Traffic Management, Austroads 2019d). In the case of three-aspect right turn arrows, red-arrow drop out method is used to achieve filter right turns in Phase A as allowed by the adjacent green circle displays (Section 6.5.3).
Number of signal faces
- East and west approaches: Three signal faces (primary, secondary and tertiary) are provided. The green circle is displayed during Phase B.
- North approach: Four signal faces (primary, dual primary, secondary, and tertiary) are provided. The primary and tertiary signal faces are three-aspect circles. The dual primary and secondary signal faces are six-aspect with three-aspect circles and three-aspect arrows. As the medians are of sufficient width, these signal faces are on posts located in the medians. The green arrow is displayed in Phase C only. The green circle is displayed in both A and C Phases and the C/A intergreen.
- South approach: Four signal faces (primary, dual primary, secondary, and tertiary) are provided. As the medians are of sufficient width, these signal faces are on posts located in the medians. All signal faces are three-aspect circles. The green circle is displayed in Phase A only.
- Pedestrian signals: Only one pedestrian signal face is required at each end of the signalised crossing as the crossing width and distance criteria are satisfied (Part 10 of the Guide to Traffic Management) (Austroads 2019d). Note that the east-west crossing distance is close to the limit value of 25 m. Pedestrian signal faces display the green Walk signal during the appropriate Phases C/A, A or B (Figure E 7 and Figure E 13).
Size of signal aspects
- Only 200 mm aspects are used as recommended in Part 10 of the Guide to Traffic Management (Austroads 2019d) since there are no grounds for providing 300 mm signals.
Use of mast arm
- The use of mast arm or overhead signal faces is not warranted at this site. For the south and north approaches, the dual primary signal face can be accommodated on the median islands as its width is greater than the 1.5 m recommended for dual column aspects of 200 mm size.
- All vehicle signal faces are provided with a target board, appropriate to the signals being used.
Visors and louvres
- Closed visors are to be provided on all secondary and tertiary signal faces except the three‑aspect right-arrow signal faces (Part 10 of the Guide to Traffic Management). The use of louvres is not warranted in this case.
Location of controller housing and signal posts
- The controller should be located in an unexposed position in close proximity to the intersection and available power supply. In Figure E 13, this is located on the south‑west corner. The posts are numbered sequentially (1 to 10) in a clockwise manner for the identification used in the cable connection diagram. Note that the number of posts has been minimised by accommodating the various signals where practicable on a common post.