Part C: Technical Guidelines - Speed Zoning

Document No:  D10#92683
 
Revision:  3A
 
Date amended:  21-Sep-2010

Image: orange line.RCN-D13^23151823.GIF

 

The information below is intended to reflect the preferred practice of Main Roads Western Australia ("Main Roads"). Main Roads reserves the right to update this information at any time without notice. If you have any questions or comments please contact Ron Koorengevel by e-mail or on (08) 9323 4704.

To the extent permitted by law, Main Roads, its employees, agents, authors and contributors are not liable for any loss resulting from any action taken or reliance made by you on the information herein displayed.

Revision Register

 

Ed/Version Number Clause Number Description of Revision Date
1 All Guideline Developed 19-Aug-2006
1A 2.2.1.2(a) Figure 1 added: Signs at the transition from a Sealed to a Gravel Road. 16-Feb-2007
1B 2.2.3.5 Drawing 200631-0022 amended. 21-Jun-2007
2 All Guideline Revised and Approved. 27-Sep-2007
2A 2.2.5.2 Sign Image of MR-RS-18 amended. 09-Jul-2009
3 All Guideline Reviewed and Revised. 02-Jun-2010
 3A Header Contact person changed. 21-Sep-2011

Table of Content


1. GENERAL

1.1 Introduction

The control of speed is an important aspect in effective traffic management. Speed zoning is used to vary the speed limit of a road or area from that which would otherwise apply under the general limit applicable to the locality. The objective of speed zoning is to provide credible speed limits which meet driver expectations while achieving a balance between road safety, land use, amenity and transport efficiency.
 
Speed limit signs are regulatory signs and therefore the creation, modification, or removal of any speed zones requires the approval of the Commissioner of Main Roads. The Commissioner has delegated his authority to the Executive Director Road Network Services and the Executive Director Infrastructure Delivery for approval of speed limits in all areas of Western Australia.



1.2 Scope
The purpose of this document is to provide a uniform approach for implementing or signposting of speed zones for a particular length of road ('linear' speed limits) or a network of roads ('area' speed limits). The policy, application & approval and administration guidelines are in separate documents.
 
This document is applicable to all public roads in Western Australia and should also be used by Local Government Authorities (LGAs) and private authorities for application to non-public roads in the state.

1.3 References

This guideline should be read in conjunction with the following documents, as appropriate

    • Main Roads Guideline - Main Roads Signs Index
    • AS1742 - Series of documents - Manual of Uniform Traffic Control Devices (Parts 1 to 15), and in particular AS1742.4-2008 (From time to time individual documents are revised, which may change or include signs that are not included in AS1742.1.  Therefore all documents relevant to a particular type of traffic control device should be referenced for advice.)
    • Austroads - Guide to Traffic Management - Part 8 : Local Area Traffic Management
    • Austroads - Guide to Road Design - Part 3: Geometric Road Design
    • Road Traffic Code 2000 - Part 3, Speed Restrictions


2. PROCEDURES

Speed limits fall into two main categories:

    • Statutory Speed Limits
    • Speed Zones


2.1 Statutory Speed Limits

Statutory speed limits are those that, by regulation in the Road Traffic Code, apply to a particular road environment, driving license provision, type of vehicle, or specific location. These speed limits are generally unsigned, with drivers expected to be aware of the limits as part of the process of obtaining and holding a driving license. Examples of this include heavy vehicle speed limits where a person shall not drive (i) a vehicle towing a trailer or other vehicle at a speed exceeding 100 km/h, or (ii) a bus with a GVM over 5t at a speed exceeding 100 km/h. An exception to this is the "WA Maximum Speeds" sign (MR-RS-1), which gives the maximum permissible speed limit in rural (undeveloped) areas for various classes of vehicles.

MR-RS-1 - WA Max Speeds Sign.GIF ​Sign MR-RS-1 (WA Maximum Speeds) may be used near the boundary of a metropolitan area where the default speed limit changes from 50 to 110 km/h. The sign may also be used on main roads into WA from adjoining states or territories to highlight the maximum permissible speed in WA.
  

Default speed limits are statutory speed limits applicable to various classes of roads according to their environment. The default speed limits applicable in Western Australia are 50 km/h for built-up areas and 110 km/h for rural or undeveloped areas.



2.2 Speed Zones

"Speed Zones" mean lengths of a carriageway defined at the beginning by means of a speed limit sign, and at the end by means of an END speed limit sign, another speed limit sign or a T-intersection where that carriageway ends.

Speed Zones can be classified as follows:

    • Linear Speed Zone - Applied to a length of road.
           - Linear speed zones less than 40 km/h;
           - Linear speed zones of 40 km/h; and,
           - Linear speed zones of 50 km/h or higher.
    • Area Speed Zone - Applied to a network of roads.
    • School Zone - Related to a school.
    • Heavy Vehicle Zone.
    • Shared Zone - Applied to an area or length of road used by both vehicles and pedestrians.

2.2.1 Linear Speed Zone

2.2.1.1. General

a) Length of Speed Zones

In order to avoid problems of continually changing speed limits along a road, particularly with the use of 10 km/h increments, it is preferable to provide minimum lengths between speed zone changes. The desirable minimum lengths of speed zones are given in Table 2.1 below (This table replaces Table 2.2 of AS 1742.4-2008):
  

Speed Limit (km/h)
Minimum Length of
Speed Zone (km)

30

0.3

40 

0.4

40 (School zone only)

0.2

50

0.5

60

0.6

60 (School zone only) 

0.3

70

0.7

80

0.8

90

0.9

100

2.0

110

4.0

Buffer zones

 

0.3 (minimum)
0.5 (preferred)

 

 

Table 2.1 - Minimum Length of Speed Zones

 

 
b) Buffer Speed Zones

 

AS1742.4-2008, Section 2.3.5, has been modified as follows. A buffer zone of intermediate speed value should be provided where there is a reduction or increase in the speed limit of more than 30 km/h, except for the following situations:

    • On exit ramps at interchanges with lengths that are insufficient to provide buffer zones of at least 300 metres,
    • At approaches to and departures from Shared Zones,
    • On entry ramps at interchanges,
    • On dual carriageway roads when the speed limit increases.

 

The length of the buffer zone should generally be 500 metres and not less than 300 metres. Buffer zones can be longer than 500 metres to include substandard vertical or horizontal alignment or hazards.

A "speed limit ahead" sign (G9-79) shall only be used in place of a buffer speed limit where there is insufficient length to install buffer speed limit signs.

c) Offset Speed Zones

Refer to AS 1742.4-2008, Section 2.3.6, unless otherwise mentioned in this document.

Where offset speed zones are used on divided roads, medians should be continuous over the length of the offset speed zone.

Main Roads does not permit offset speed zones on undivided roads, for permanent installations.

d) Road Characteristics

AS 1742.4-2008 Appendix A Section A3 shall be used except for sub-section A3.4 - Road Hazards, which is replaced with the following:

Speed limits should not be reduced for isolated road hazards such as un-signalised intersections, driveways, railway level crossings and isolated curves. Hazards such as these should be treated with the appropriate warning and regulatory signs, and where necessary advisory speed signage. However, where several hazards occur in close proximity to each other over a section of road 3 km or more, then a lower speed limit than that indicated by roadside development may be appropriate.

Traffic Signals, Roundabouts and Single Lane Bridges/Floodways are speed zoned as follows:

    • Where the approach road is speed zoned at 90 km/h and above, the approach shall be a speed zone not greater than 80 km/h with a length not less than 300 metres on the approach side of the road feature.
    • On divided carriageways, if offset speed zones are appropriate, the length of the speed zone should be reduced to 100 metres on the departure side of the road feature.
    • Due to the potential for high severity head-on and head-on evasion crashes at single lane bridges and floodways, associated traffic control devices should be provided in addition to normal speed zoning devices. (Refer to Main Roads policy on "Give Way Signs Approaching Narrow Roads and One Way Bridges", available under on-line documents for Main Roads staff).


e) Location of Speed Zone Change

Except on divided carriageways where offset speed zones can be used, it is desirable that speed zone changes occur in advance of major intersections to avoid distractions and to allow drivers to adapt to the lower speed limit before reaching the intersection. A typical distance of 300 metres is desirable where appropriate conditions exist. However, where the speed zone is lower on the departure side of the intersection (for instance on the terminating leg of a T-junction), the speed zone change should be installed as near as possible to the intersection (100m in rural areas, 50m in urban areas) to discourage continuation of the higher travel speeds after the intersection.

Road sections in linear speed zones with a speed limit of 40 km/h shall be fully contained within a recognisable and dedicated tourist, recreation, conservation, shopping, commercial or industrial area or precinct or reserve subject to the following:

    • The start and end of the road section should have appropriate threshold treatments installed, and,
    • Mid-block speed-reducing devices shall be provided where the length exceeds 400 metres, or where devices are necessary to create a speed environment consistent with the speed zone. Reference should be made to the Main Roads "Local Area Traffic Management" guideline and the Austroads publication, "Guide to Traffic Management - Part 8 - LATM".

2.2.1.2 Signs

a) General

The signs on linear speed Zones are to be installed in accordance with AS1742.4-2008 Section 3, other than the following practices which are adopted in Western Australia. 

Only the Speed Restriction sign (R4-1) and the "End Speed Limit" sign (MR-RS-21 / R4-12) should be used for new linear speed zoning applications in Western Australia. (Previously, the Australian Standard "End Speed Limit "sign (R4-12) was a different size to the Main Roads "End Speed Limit" sign MR-RS-21, (which is the same size as the  R4-1 sign). Since these signs are frequently installed back-to-back, as indicated in Figure 1, the Main Roads version was preferred. Now, the R4-12 sign is the same size as the MR-RS-21 sign and the two may be used interchangeably.

The speed restriction sign is used to indicate the speed limit that applies to the speed zone or general built-up area limit about to be entered and as a repeater sign.  The "End Speed Limit" sign is used at the end of a speed zone or Built-Up Area Speed Limit and indicates that the default general speed limit applies beyond the sign.

It should be noted that the Speed Derestriction sign (R4-2) has been installed in the past in lieu of the "End Speed Limit" sign, and some of these signs may still be in use. However, this practice is no longer supported, and these signs should gradually be phased out and replaced with End Speed Limit (MR-RS-21 / R4-12) signs. The signs to be used at the transition from a sealed to a gravel road are shown in Figure 1.

 

sign at the transition from a sealed to a gravel road.GIF

Note:  Posted speed and required sign size may vary.

Figure 1: Signs at the Transition from a Sealed to a Gravel Road

 

 

MR-RS-21C.GIF The END Speed Limit sign (MR-RS-21 / R4-12) shall be used at the start point of a continuous section of road covered by the general rural speed limit where it is not practicable or desirable to indicate the speed limit applying beyond the point by means of a Speed Restriction (R4-1) sign.  This would be the case where the safe operating speed of the alignment beyond the start point is substantially lower than the general rural speed limit (such as a gravel road) or if there is a hazard such as a busy intersection or railway level crossing just beyond the start of the limit and it is not appropriate to extend the posted speed into this area.

 

 

b) Speed Limit Signs Used with Other Signs

In general, no other sign should be erected on any post carrying a speed limit sign. The only exceptions are:

    • "END OF FREEWAY" (MR-GE-23) and "START OF FREEWAY" (MR-GE-22) supplementary plates, which may be added to the bottom of freeway speed limit signs (refer to clause 2.2.1.2 g).
    • "End Speed Limit" sign (MR-RS-21 / R4-12), which may be erected back-to-back with a speed limit sign, as indicated in Figure 1.
    • "End Area Speed Limit" sign (MR-RS-20), which may be erected above a speed limit sign (refer to clause 2.2.2.2) to indicate the end of a speed limited area and the start of a linear speed zone.
    • "End School Zone" sign (R4-9), which may be erected above a speed limit sign to indicate the end of a school zone and the start of a linear speed zone. If the default urban speed limit of 50 km/h applies after the sign, the "End School Zone" sign shall be installed without a speed limit sign.
    • "School Zone" (R4-8) and "Times of Operation" supplementary plates (MR-RS-11 and MR-RS-12), together with a R4-1 speed limit sign were used in the past in lieu of the School Zone signs (MR-RS-7B, MR-RS-8B and MR-RS-14B). Although some of these sign combinations may still be in place, current practice is to use the Main Roads School Zone signs (MR-RS-7B, MR-RS-8B, MR-RS-9, MR-RS-14B, MR-RS-15B and MR-RS-16B) - clause 2.2.3.4 refers.
    • "VEHICLES 22.5t GCM OR MORE" (MR-RA-21) supplementary plate is used together with a R4-1 speed limit sign as a repeater sign for Heavy Vehicle Speed Zones as per clause 2.2.5.2.

 

c) Repeater Signs

This section supersedes clause 3.2.7 of AS1742.4-2008.
  
Repeater signs are used:

    • To remind drivers of the speed limit.
    • To advise drivers where the zoned speed or the general built-up area limit might appear inconsistent with surrounding development.
    • To advise drivers turning into a speed zoned road from an important intersection.
    • To confirm a zone limit after a discontinuity Such as a "Y" junction where a road name change occurs. 

 

The location, spacing and number of repeater signs is given in clauses 2.2.1.2(e) and 2.2.1.2(f) of these guidelines, respectively.

 

 

d) Size of Signs

The sizes of signs used in Western Australia are given in Tables 4 and 5 of the Sign Standard Guidelines. As a general rule, speed zone change signs are size "C" and repeater signs are size "B". Exceptions to this are:-

Perth Metropolitan Areas

    • Freeways and Controlled Access Highways - use size "C" signs in both instances.
    • Local Access Roads - use size "B" in both instances.
    • Local Access Roads, where V85 < 40 km/h - use size "A".

 

Areas outside of Perth Metropolitan Area

    • Roads in residential areas in rural townsites - use size "B" in both instances.

    • Local Access Roads with speed limit = 60 km/h - use size "B" in both instances.

    • Local Access Roads, where V85 < 40 km/h - use size "A".

 

e) Location and Spacing

(i) Speed Zone Change Signs

As per subclause 2.2.1.1(d), where the approach road is speed zoned at 90 km/h and above, the approach to a roundabout or signalized intersection shall be speed zoned not greater than 80 km/h at a distance not less than 300 metres on the approach side of the intersection by the installation of speed zone change signs.

On divided carriageways, if offset speed zones are appropriate, the length of the speed zone should be reduced to 100 metres on the departure side of the road feature.

As per subclause 2.2.1.1(e), speed zone change signs located downstream of a T-Junction on the terminating leg should be installed approximately 50 to 100m from the intersection.

 

(ii) Repeater Signs in Urban Areas subject to Built-up Area Speed Limit

In urban areas subject to the built-up area speed limit where signage is installed, repeater signs should be provided at intervals of approximately 1.0 km or on the departure side of major intersections as follows:

    • Downstream of an intersection on a terminating leg: 50 - 100m
    • Downstream of an intersection on a continuing leg: 100 - 200m

It should be noted that it is not Main Roads practice to install speed limit signs on roads subject to the built-up area default speed limit.

 

(iii) Repeater Signs in Urban Areas not subject to the built-up area speed limit

In urban Areas not subject to the built-up area speed limit, repeater signs shall generally be located at the intervals given in Table 2.2, or on the departure side of major intersections as follows:

    • Downstream of an intersection on a terminating leg: 50 - 100m
    • Downstream of an intersection on a continuing leg: 100 - 200m

Repeater signs may also be required where roadside development alters markedly without a change in speed zone.

 

Speed Limit
(km/h)
Maximum Spacing for
Repeater
Signs (km)

40 (Heavy Vehicle Speed Zone) 

1.0 (Refer to Clause 2.2.5.2)

50

1.0

60

1.0

70

1.0

80

1.5

90

1.5

100

3.0

110

4.0

 

Table 2.2 Maximum Spacing of Repeater Signs for Urban / Outer Urban Areas

 

(iv) Repeater Signs in Rural Areas

In rural areas, repeater signs shall be erected on the departure side (between 50 - 100m on terminating legs, and between 100 - 200m on continuing legs) of intersecting classified roads or any other roads carrying 75 vehicles per day or more, that intersect with the speed zoned road.  Generally, these signs shall be spaced no closer than 0.5 km. 

In the more developed rural areas, the maximum spacing of repeater signs after consideration of signing at major intersections may vary between 5 and 10 km, depending upon the level of roadside development.  In remote rural areas repeater signing may be erected at 10 to 20 km spacing.  In areas north of Meekatharra and Kalbarri and east of Norseman, repeater signs can be erected at greater intervals of about 25 to 50 km where there are low traffic volumes and long travel distances without a change of speed limit or intersecting roads.

 

f) Position and Number of Signs

(i) Speed Change Signs

Speed Change signs (R4-1) shall be doubled up and placed on the left hand and right hand side verges in the case of single carriageway roads and the left hand side verge and median side verge in the case of dual carriageway roads. The signs applying to a particular direction of travel shall not be staggered.

(ii) Repeater Signs

Repeater signs are single Speed Restriction signs (R4-1) mounted as follows:

    • On single carriageway roads - on the left hand side verge [Refer to Figures 2(a) & (b)].
    • On dual carriageway roads with two or more lanes - on both the left hand side verge and median side verge of the carriageway, staggered by approximately 100m [Refer to Figure 2(e)].

Figures 2(a) to 2(e) provide guidance on the location of speed zone signs in the vicinity of an intersection for a variety of scenarios.

 

location of speed zone signs - figure 2a.GIF

Figure 2(a): Location of Speed Zone Signs - Single Carriageway Roads, Unsignalised Intersection -

Terminating Road Speed < Through Road Speed

 

location of speed zone signs - figure 2b.GIF

Figure 2(b): Location of Speed Zone Signs - Single Carriageway Roads, Unsignalised Intersection -

Terminating Road Speed = Through Road Speed

 

location of speed zone signs - figure 2c.GIF

Figure 2(c): Location of Speed Zone Signs - Single Carriageway Roads, Signalised Intersection -

Terminating Road Speed = Through Road Speed

 

 

location of speed zone signs - figure 2d.GIF

Figure 2(d): Location of Speed Zone Signs - Dual Carriageway on Main Road, Signalised Intersection -

Terminating Road Speed = Through Road Speed

 

location of speed zone signs - figure 2e.GIF

Figure 2(e): Location of Speed Zone Signs - Dual Carriageway (two or more lanes)
on Main Road, Unsignalised Intersection

 

g) Freeway Exit and Entry Ramps

Advisory speed signs for freeway exit ramps shall be signed in accordance with AS 1742.2 - 2009, clause 3.5(e).

Speed Restriction signs (R4-1) shall be installed as per Figures 3 and 4. These figures supersede Figures 3.1 and 3.2 of AS1742.2 - 2009 respectively.  MR-GE-22 and MR-GE-23 signs are used in conjunction with R4-1 (Speed Limit) signs as described below:

mr-ge-22.GIF The MR-GE-22 (START OF FREEWAY) sign shall be used as a supplementary plate with a Speed Restriction sign (R4-1) to indicate the beginning of freeway conditions. When used under these circumstances, the MR-GE-22 sign shall be used in lieu of the Australian Standard GE6-13 (START OF FREEWAY) sign.
 
mr-ge-23.GIF

The MR-GE-23 (END OF FREEWAY) sign shall be used as a supplementary plate with a Speed Restriction sign (R4-1) to indicate the end of freeway conditions. When used under these circumstances, the MR-GE-23 sign shall be used in lieu of the Australian Standard GE6-11 (END OF FREEWAY) sign.

 

typical rural interchange.GIF

 Notes:
1.

EXIT SPEED - used only if required [see Clause 2.2.1.2(g)]

2.

Sign MR-RM-21 shall be duplicated on ramps with more than one lane.  In addition, the advance information sign PROHIBITED ON FREEWAY (MR-GE-25) shall be erected on the approaches to the local road/freeway on-ramp intersection.

3. Sign R5-58 is required near this location to prevent stopping on the freeway.
4. See Figure 4 where cross-road is divided, i.e. adapt treatment from urban case.
5. Signs R2-4 and GE9-15 must be sited and angled to cover all potential wrong-way turning movements.
6. R4-1 signs (along with MR-GE-22 or MR-GE-23 supplementary plates, if used) shall be duplicated on both sides of the carriageway regardless of the number of lanes on the ramp at that point.

Figure 3: Typical Rural Interchange

 

 

typical urban cross street with ramp treatment.GIF

Notes:
1. R4-1 signs (along with MR-GE-22 or MR-GE-23 supplementary plates, if used) shall be
    duplicated on both sides of the carriageway regardless of the number of lanes on the
    ramp at that point.

                           Figure 4: Typical Urban Cross Street with Ramp Treatment

 

2.2.1.3  Pavement Markings

a) Longitudinal

For two-lane, two-way roads, it is desirable that a dividing line or barrier line is provided on a section of road that is speed zoned. 

 

b) Numerals

Numerals may be installed where considered appropriate to supplement speed limit signs on the approaches to a road section in accordance with Clause 3.1.4 of the Approval and Application Guidelines and AS 1742.4 - 2008 Section 3.4.  Where provided, the following shall apply:

    • Markings shall be 5m long where the approaching traffic is in a speed zone of 90km/h or more.
    • The numerals shall be installed in each marked lane. 
    • Pavement markings shall not be installed on a curve.


 

2.2.2 Area Speed Zones

Area speed zones shall have appropriate signs erected at every entry and exit point in accordance with the clauses 2.2.2.1 to 2.2.2.4.

 

2.2.2.1 Entry signs

Speed Limit AREA signs (R4-10) shall be placed on both sides of the road to face traffic entering the zone.  They shall be positioned approximately 30 to 50m from any intersection to enable them to be readily seen by drivers after they have turned from the intersecting street.  (Refer to Figure 5).

 

2.2.2.2 Exit Signs

The exit signs required for speed zone areas depend on the type of roadway (continuing or terminating) and the speed limit of the road after passing the exit sign.  With reference to Figure 5:

 

 R4-11B.GIF

For terminating roads, END Speed Limit AREA signs (R4-11) shall be placed on both sides of the road, back-to-back with the Speed Limit AREA signs (R4-10).

For continuing roads, where the speed limit of the continuing road is the default speed limit, END Speed Limit AREA signs (R4-11) shall be placed on both sides of the road, back-to-back with the Speed Limit AREA signs (R4-10).

 

 

MR-RS-20B.GIF For continuing roads, where the speed limit of the continuing road is not the default speed limit, END Speed Limit AREA signs (MR-RS-20), together with Speed Limit signs (R4-1) shall be placed on both sides of the road, back-to-back with the Speed Limit AREA signs (R4-10). 

 

 

application of area speed zone signs.GIF

Figure 5: Application of Area Speed Zone Signs

 

2.2.2.3 Repeater Signs

Area Speed signs (R4-10) are to be used as repeater speed limit signs and shall be installed within the speed limited area at approximately 500 metre intervals on each continuous street that is longer than 1000 metres.

 

2.2.2.4 Sizes of Area Speed Zone Signs

For sizes of Area Speed Zone signs, refer to Section 2.2.1.2(d).


2.2.3 School Zones

School Zones can be applied to particular roads in the vicinity of pre-primary, primary and secondary schools to reduce traffic speeds at times of the day when school children are likely to be present on or about these roads.

 

2.2.3.1 Speed Limits

The appropriate school zone speed limits are as follows:

    • 40 km/h school zone - within 50, 60 and 70 km/h speed zones.
    • 60 km/h school zone - within 80 and 90 km/h speed zones.

 

2.2.3.2 Times of Operation

To ensure statewide uniformity the following times of operation are used on School Zone signs. These standard times allow for the variations in individual school start and finish times.

- Northern Region:          7.30 AM - 9.00 AM and 2.00 PM - 3.30 PM
- Carnarvon Area:           7.30 AM - 9.00 AM and 2.00 PM - 4.00 PM
- All other areas of WA    7.30 AM - 9.00 AM and 2.30 PM - 4.00 PM

All times of operation within a town or city shall be consistent. Times may vary marginally between towns.

 

2.2.3.3 Length of School Zones

School zones should extend at least the full length of the school frontage.  Generally, school zones extend about 50 m beyond the school frontage to effectively cover children crossing in the vicinity of the school.

The minimum length of a school zone along the main school frontage should generally be not less than:

    • 200 metres where the school zone speed limit is 40 km/h.
    • 300 metres where the school zone speed limit is 60 km/h.

 

Where a school zone is also installed on a secondary school frontage road, the length of the school zone may be considerably less than that specified for the main frontage.

The actual lengths of school zones should be determined from the needs of the individual school, having regard for the type of road, traffic volume, traffic speed, visibility and road conditions. Where possible, the school zone on the main school frontage should be installed such that the point at which most students enter and leave the school is centred within the school zone.

The existence and location of school crossing facilities (such as children's crossings, marked pedestrian crossings, or pedestrian refuges) should be taken into account in determining the length of the school zone.  The school zone should extend over a length sufficient to include any such facilities in the immediate proximity of the school.

Where two schools are nearby, both independently satisfying the selection criteria, one continuous school zone serving both schools shall be applied if the separation distance between separate school zones is 300 metres or less.

2.2.3.4 School Zone Signs

a) Current Practice

The start of a school zone shall be defined by a "School Zone" sign indicating the reduced speed limit and the times and days of operation.  In Western Australia, the preferred practice is that the Australian Standard signs R4-8 (school zone), R4-1 (speed restriction) and R9-1-2 (times of operation) are combined into a single "School Zone" sign. Figure 6 illustrates a typical school zone sign layout. It should be noted that "Enhanced School Zone" signs shall only be used at the start of the zone along those roads which front onto the school site. "Enhanced School Zone" signs have a five-sided fluorescent orange "hat", which may be part of the sign (MR-RS-15B and MR-RS-16B), or which may be attached as a separate plate (MR-RS-17) to a School Zone sign (MR-RS-7B, MR-RS-8B, MR-RS-9B or MR-RS14B).

 

mr-rs-7.GIF

The MR-RS-7B (School Zone - all regions except Northern Regions) sign is used to sign a school zone speed limit of 40 km/h in all areas of Western Australia where the speed zone (outside of school hours) is 50, 60 or 70 km/h, other than the Northern Region (Gascoyne, Pilbara and Kimberley Regions).

This sign may be used in conjunction with a MR-RS-17 "Supplementary Plate to Enhance School Zone Signs" at the start of a school zone on those roads which front onto the school site. This sign may be used at the start of a school zone on roads which terminate on roads which front onto the school site. This sign may also be used on its own as a repeater sign within the school zone.

 

 

MR-RS-8B.GIF

 

The MR-RS-8B (School Zone - Northern Regions) sign is used to sign a school zone speed limit of 40 km/h in all Northern Regions of Western Australia (Gascoyne, Pilbara and Kimberley Regions) where the speed zone (outside of school hours) is 50, 60 or 70 km/h, other than in the town of Carnarvon.

This sign may be used in conjunction with a MR-RS-17 "Supplementary Plate to Enhance School Zone Signs" at the start of a school zone on those roads which front onto the school site. This sign may be used at the start of a school zone on roads which terminate on roads which front onto the school site. This sign may also be used on its own as a repeater sign within the school zone.

MR-RS-14B.GIF

 

The MR-RS-14B (School Zone - Carnarvon) sign is used in the town of Carnarvon only to sign a school zone speed limit of 40 km/h where the speed zone (outside of school hours) is 50, 60 or 70 km/h.

This sign may be used in conjunction with a MR-RS-17 "Supplementary Plate to Enhance School Zone Signs" at the start of a school zone on those roads which front onto the school site. This sign may be used at the start of a school zone on roads which terminate on roads which front onto the school site. This sign may also be used on its own as a repeater sign within the school zone.

mr-rs-9.GIF

 

The MR-RS-9B (School Zone) sign is used to sign a school zone speed limit of 60 km/h in all areas of Western Australia where the speed zone (outside of school hours) is 80 or 90 km/h, other than the Northern Region (Gascoyne, Pilbara and Kimberley Regions).

This sign may be used in conjunction with a MR-RS-17 "Supplementary Plate to Enhance School Zone Signs" at the start of a school zone on those roads which front onto the school site. This sign may be used at the start of a school zone on roads which terminate on roads which front onto the school site. This sign may also be used on its own as a repeater sign within the school zone.

 MR-RS-15B.GIF

 

 

The MR-RS-15B (Enhanced School Zone - all regions except Northern Regions) sign is used to sign the start of a school zone speed limit of 40 km/h on those roads which front onto the school site in all areas of Western Australia where the speed zone (outside of school hours) is 50, 60 or 70 km/h, other than the Northern Region (Gascoyne, Pilbara and Kimberley Regions).

 MR-RS-16B.GIF

 

 

The MR-RS-16B (Enhanced School Zone - Northern Regions) sign is used to sign the start of a school zone speed limit of 40 km/h on those roads which front onto the school site in all Northern Regions of Western Australia (Gascoyne, Pilbara and Kimberley Regions) where the speed zone (outside of school hours) is 50, 60 or 70 km/h, other than in the town of Carnarvon.

 

MR-RS-17-s.GIF

The MR-RS-17 (Supplementary Plate to Enhance School Zone Signs) sign may be used with the School Zone signs MR-RS-7B, MR-RS-8B, MR-RS-9 and MR-RS-14B to sign the start of a school zone speed limit on those roads which front onto the school site. The sign is normally used to retrospectively convert an existing "School Zone" sign to an "Enhanced School Zone" sign. This sign may also be used for maintenance purposes where the fluorescent orange "school zone" panel has faded in a MR-RS-15B or MR-RS-16B sign.

 

MR-RS-22B.GIF

 

 

The MR-RS-22B (Enhanced School Zone all regions except Northern Regions) sign is used to sign the start of a school zone speed limit of 60 km/h on those roads which front onto the school site in all areas of Western Australia where the speed zone (outside of school hours) is 80 or 90 km/h, other than the Northern Region (Gascoyne, Pilbara and Kimberley Regions).

R4-9.GIF

The "End School Zone" sign (R4-9) is a regulatory sign and shall be used to identify the end of a school zone. Where the speed limit beyond the school zone is subject to a speed zone greater or less than the general built-up area or rural limit, the "End School Zone" sign shall be installed in conjunction with the appropriate speed restriction sign. Where the speed limit beyond the school zone is the same as the general built-up area or rural limit, the "End School Zone" shall be installed on its own. On two-lane, two-way roadways, the "End School Zone" sign is generally installed back-to-back on the same post as the "School Zone Sign" (refer to Figure 6). It should be noted that the "End of School Zone" sign (MR-RS-13) is no longer used, although it is still supported under the Road Traffic Code 2000.

 

With reference to Figure 6, the following installation principles apply to School Zones:

    • For two-lane two-way roads leading directly past the school, the start of a School Zone should have "Enhanced School Zone" signs on both sides of the road. The end of the school zone should have "End School Zone" signs on both sides of the road, fixed back to back on a single post with the "Enhanced School Zone" signs. 
    • For two-lane, two-way roads with a raised refuge island, or for four-lane divided roads with a narrow median (smaller-equal.GIF 2m) leading directly past the school, the start of a School Zone should have "Enhanced School Zone" signs on the left hand side and the central median. The end of a School Zone should have "End School Zone" signs on the left hand side and the central median. The signs in the central median shall be fixed back to back on a single post.
    • For four-lane divided roads with a wide median (> 2m) leading directly past the school, the start of a School Zone should have "Enhanced School Zone" signs on the left hand side and the central median. The end of a School Zone should have "End School Zone" signs on the left hand side and the central median. All signs shall be mounted on their own posts.
    • For roads joining onto roads leading directly past the school, the start a School Zone is indicated by a School Zone sign installed on the left hand side of the road. The End of School Zone sign is attached back to back on the same post.
    • Signs are not required on loop roads that have both ends within the school zone and which fronts onto the school site or cul-de-sacs less than 200 m long.
    • School Zone signs may be repeated to reassure drivers that they are still within the school zone if the lengths of the frontage roads are greater than 300m.
    • Size 'B' School Zone signs shall be used in all cases, unless only one size is available.

 

typical-school-zone-sign.GIF

Figure 6: Typical School Zone Sign Layout

 

b) Signing Practices that are no longer current

The following signing practices are no longer current, although there may still be installations employing these practices on the road network. Any such installations should be replaced with signs complying with current practice, when these signs become due for replacement under the Term Network Contract maintenance agreements.

Where the preferred practice of combining the individual Australian Standard signs R4-8 (school zone), R4-1 (speed restriction) and R9-1-2 (times of operation) into a single "school zone" sign indicated in clause (a) above, is not adhered to, the following has been applied. 

 

 mr-rs-11.GIF

The MR-RS-11 sign has been used in the past in lieu of the Australian Standard "Times of Operation" sign 9-1-2 and in conjunction with the Australian Standard "School Zone" sign (R4-8B) and Speed Restriction sign (R4-1B) to indicate the times a school zone speed restriction applies in all regions of Western Australia, other than the Northern Regions (Gascoyne, Pilbara and Kimberley regions). Current preferred practice is to use the Main Roads signs MR-RS-7B and MR-RS-9B.

mr-rs-12.GIF

The MR-RS-12 sign has been used in the past in lieu of the Australian Standard "Times of Operation" sign 9-1-2 and in conjunction with the Australian Standard "School Zone" sign (R4-8B) and Speed Restriction sign (R4-1B) to indicate the times a school zone speed restriction applies in all Northern Regions of Western Australia (Gascoyne, Pilbara and Kimberley regions). Current preferred practice is to use the Main Roads sign MR-RS-8B.

mr-rs-10.GIF

The "Direction Arrow" sign (MR-RS-10) was used in the past in conjunction with signs MR-RS-7B, MR-RS-8B, MR-RS-9 and MR-RS-14B to indicate to drivers approaching a School Zone from a side road that the road they are joining is zoned as a "School Zone". The sign was positioned opposite the T-junction, facing terminating traffic. This practice is no longer necessary (Figure 6 refers) and is being phased out. 

 

2.2.3.5 Road Markings

    • For school zones "40" or "60" pavement markings, comprising a yellow rectangle with black numerals, are only installed on the main entry points to the school zone, adjacent to the first school speed zone sign where warrants are met (refer to the Approval and Application Guidelines).
    • On multi-lane carriageways, separate patch pavement markings shall be provided in each lane. 
    • Patch pavement markings shall not be installed on a curve, or within the swept path at intersections.
    • Markings shall conform to the layout shown below and detailed in Main Roads standard drawing nos. 200631-0022 and 200731-0037 for 40 km/h and 60 km/h respectively.

school-zone-40-60.GIF

Figure 7: School Zone "40 km/h" and "60 km/h" Pavement Markings

 


2.2.4 Shared Zones

2.2.4.1 General

A Shared Zone is a length of carriageway or a network of roads in an area on which vehicular traffic must give way to pedestrians, where the road environment has been adapted for low vehicle speeds and on which the speed limit is 10km/h by law. 

2.2.4.2 Signs

Signs should be installed in accordance with AS1742.4-2008, Section 3.2.6.


2.2.5 Heavy Vehicle Speed Zones

2.2.5.1 General

The Road Traffic Code 2000 allows the implementation of Heavy Vehicle Speed Zones, restricting the speed of heavy vehicles to the speed limit indicated by numbers shown on the 'heavy vehicle speed zone' sign. The Code defines a heavy vehicle as 'a vehicle, other than a bus, that has, or together with any attached trailer and its load has, a Gross Combined Mass (GCM) that is 22.5 t or more'. In the context of this definition, the speed restriction would also apply to a vehicle having a Gross Vehicle Mass (GVM) of 22.5 t or more.

The preferred speed zone restriction for heavy vehicles is 40 km/h, but this may be varied depending upon the situation. Conditions applicable for the installation of Heavy Vehicle Speed Zone signs are given in Section 3.3 of the Approval and Application guidelines.

 

2.2.5.2 Signs

MR-RS-18.GIF

    

Sign MR-RS-18 (Heavy Vehicle Speed Zone) shall be erected at the start of a length of carriageway to which a heavy vehicle speed zone applies. 

 

mr-rs-19.GIF 

Sign MR-RS-19 (End of Heavy Vehicle Speed Zone) shall be erected at the end of a length of carriageway to which a heavy vehicle speed zone applies.  

 

R4-1B.GIF

 

Signs R4-1B and MR-RA-21 shall be used as repeater signs for Heavy Vehicle Speed Zones and shall be located at approximately 1.0km intervals, or 50m past any repeater signs indicating the speed limit for other vehicles.


2.2.6 Advisory Speed Signing

Advisory speed signing shall be limited to horizontal and vertical curves (including LATM devices) on sealed roads. These are signed with curve warning and advisory speed signs in accordance with AS 1742.2 - 2009 Section 4.4, unless otherwise directed in this guideline. Advisory speed signing for freeway exit ramps is to be in accordance with Clause 2.2.1.2(g) of these guidelines.

Wherever possible it is preferable to determine advisory speeds by field assessment. For existing roads, the determination of advisory speeds for substandard curves shall be undertaken in accordance with the methods given in Appendix F of AS 1742.2-2009. Where there is a need to determine safe operating (advisory) speed from design drawings, the following formula shall be used, and the advisory speed shall be set at the nearest 5km/h increment below the calculated safe operating (advisory) speed. 

V2 = R x 127 x (e + f)

Therefore,

 equation3.GIF

Where:

V = Speed in kilometres per hour.
R = Radius of curve.
e = superelevation in m/m.
f = side friction factor.

If not known, the side friction factor should be determined by referral to the following document: Austroads - Guide to Road Design - Part 3: Geometric Road Design.

Where there is a series of more than two closely spaced horizontal curves, some or all of which are substandard, the symbolic "Winding Road" sign (W1-5) shall be used at the beginning of the series of curves. The winding road sign used shall indicate the direction of the first substandard curve and the advisory speed sign shall indicate the advisory speed of the slowest curve. However, if the series of curves extends over a distance of one kilometre or more and the slowest curve is more than 10 km/h slower than the others, the slowest curve is to be signed separately.

If the crash level on a section of speed zoned road with advisory speed signing becomes greater than the network average for that type of road, then that road section may be speed zoned at a lower value, as indicated in Clause 3.1.4.3 of the Approval and Application guidelines.