Hierarchy

First Level Warning

W12-1.1 (L)/(R) – W12-2.4 (L)/(R)

As per description in Table 3‑1 (Typical horizontal alignment advance curve warning signs).

Table 3-1

2nd Level Warning

W12-3.2

If curve advisory speed is warranted add W12-3.2 Curve sign supplementary – advisory speed.

3rd level warning

W12-3.2
W20-1

If the required speed reduction is large (ie C or D Curve sign supplementary – advisory speed sign warranted, refer Appendix A:) or for demonstrated safety reasons, add Chevron sight board – horizontal curve.

Appendix A: Guidelines for the installation of curve warning and advisory speed signs

W20-1 (L4)/(R4) (four chevrons) are the preferred Chevron sight board for all installations; however, where the available space does not permit their installation, a W20-1 (L2)/(R2) Chevron sight board may be installed.

Chevron sight boards – horizontal curve must include a curve advisory speed.

Alternative 3rd level warning

W12-3.2
W20-2 (L)/(R)

These can be used where the curve is long and better delineated by Chevron curve indicators. The spacing of Chevron curve indicators should be small enough that at least two are visible to road users as they negotiate the curve.

The Curve sign supplementary – advisory speed may be omitted.

4th level warning

W12-3.2

W20-1

W20-2 (L)/(R)

If 3^rd level applies and a long curve exists, then add Chevron curve indicators as necessary:

W20-1 (L4)/(R4) Chevron sight board (with four chevrons) are the preferred sign for all installations; however, where the available space does not permit their installation, a W20-1 (L2)/(R2) Chevron sight board may be installed.

Note: Pursuant to TCD Rule, W20-1 Chevron sight boards must include an advisory speed. A minimum of two Chevron curve indicators should be visible to road users as they traverse the curve.

5^th level warning

W19-2.1

Refer to the active warning signs and variable lane controls section for information on their use. 

Active warning signs and variable lane controls