MUTCD Part 4 Speed Controls
Supplement
Manual of Uniform Traffic Control Devices (MUTCD)
Part 4: Speed Controls
May 2016
Copyright
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© State of Queensland (Department of Transport and Main Roads) 2016
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Manual of Uniform Traffic Control Devices, Transport and Main Roads, May 2016
Contents
4.5.2-1 Speed reduction on approaches to controlled high speed rural intersections ..........7
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8 Circumstances where a 50 km/h speed limit should not be applied --------------------------- 18
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3 Application of criteria based speed limits
3.5 Speed limits in special speed zones
3.5.3 Speed limits on foreshores
3.5.3-1 Setting speed limits on foreshores
1 Purpose
The purpose of this section is to provide guidance for implementing Section 3.5.3 of Manual of
Uniform Traffic Control Devices (MUTCD) Part 4: Speed Controls. It outlines the factors to be considered in setting a foreshore speed limit, speed limit approval process and signage requirements at the foreshore.
2 Background
The foreshore is defined as the land lying between high-water mark and low-water mark and is state controlled. Under Section 936 of the Local Government Act, 1993 (LGA), a local government may seek authority for administration of the foreshore. Where this authority is given, the local government may make a Local Law under Section 66(3) (h) of the Transport Operations (Road Use Management)
Act, 1995 regarding the regulation of the driving of vehicles or animals on the foreshore.
There are many variables on the foreshore that may change over time of day or year. Tidal flows influence the width of the foreshore that is available for driving or for conducting other beach activities.
Similarly, seasonal factors determine the volume of both pedestrian and traffic activity on a foreshore.
Other environmental factors such as washouts etc. also influence driving speeds on the foreshore as well as activities such as camping, hang gliding, the preservation of native and endangered species.
This supplement applies to foreshores where vehicles may be driven on the foreshore and where the
General Rural speed limit (e.g. 100 km/h) may be considered to be inappropriate due to the level of pedestrian and other activities on the foreshore.
3 Speed limit
The speed limit applicable on a foreshore may vary depending on a number of factors including driving conditions on the foreshore, tidal movement, seasonal factors that influence numbers of pedestrians and vehicles on the foreshore, type of activity on the foreshore, and the frequency of activity. If there is no posted speed limit on the foreshore, the General Rural speed limit will apply and drivers will choose a speed that they are comfortable with, depending on the variables.
Where a posted speed limit is to apply on the foreshore, the speed limit should be based on a consideration of the peak pedestrian volume and activity on the foreshore. Setting a speed limit based on pedestrian volume and activity that happens only at certain times of the year or where the activity or foreshore conditions vary significantly may not suit some motorists during non-peak periods and may result in non-compliance with the speed limit during these periods.
The speed limit permitted on the foreshore should be based on the assumption that the conditions on the foreshore are ideal for driving e.g. it is free of washouts and the sand is well compacted. This may not always be the case but the speed limit represents the maximum safe speed under these ideal conditions. The local government must consult with representatives from the Department of Transport and Main Roads and Queensland Police Service. It may also consult with representatives from the departments responsible for managing environment, natural resources, parks and wild life, marine
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Part 4: Speed Controls parks and any other stakeholder. Consultation with other agencies that may have an interest is encouraged.
4 Location of signs
Section 322 of the Transport Operations (Road Use Management) (TORUM) Regulation, 1999 requires traffic control signs to be installed in manner that it is clearly visible to road users to whom it is designed to apply. Under Sections 327 and 340 of TORUM Regulation, 1999 , the speed limit sign only applies to a driver if he faces the sign before passing it.
The MUTCD provides guidelines for the installation of speed limit signs on formed roads. Generally signs are installed on the left hand side of the carriageway on a two way formed road. On a foreshore, it is not practical to install signs on both sides of the area used for driving. If speed limit signs are not readily visible to the driver, compliance with the speed limit may be low and could have a negative impact on the safety of pedestrians on the foreshore.
5 Frequency of signage
Consideration should be given to installing speed limit signs at more frequent intervals than required under the speed zoning guidelines. However, the road authority may vary the spacing and location of signs to suit with the local foreshore condition considering risks and benefits associated with the installation of signs.
6 Size of signs
It is suggested that the largest signs (D – 1200 x 1600) be considered for installation to ensure that the speed limit is always visible to drivers in the direction of travel. However, this may always not be feasible. Care should be given to the effect of wind on the stability of the signs as formed concrete foundation would not be feasible due to both temporary nature of vehicular path and high cost of such installation. The road authority may choose smaller size signs if it considers that installation of larger signs would not be in the interest of public safety.
7 Approval of speed limit
On foreshores where a speed limit is applied for the safety of beach users, the appropriate speed limit shall be recommended by the relevant road authority. Usual MUTCD process shall apply for the approval of foreshore speed limit.
8 Approval of signage plan
The road authority shall prepare a signage plan in consultation with relevant stakeholders. The signage plan should be endorsed by the local Speed Management Committee before its implementation.
9 Speed enforcement
Where the foreshore speed limit is proposed for enforcement by speed camera, the location of the speed camera zone should be endorsed by the local Speed Management Committee together with the speed signage plan.
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3.7-1 Speed limits at bridges
Where it is necessary to limit vehicle speeds on a bridge or floodway due to structural deficiencies, a reduced speed zone shall be established in accordance with this supplement.
The Speed Restriction (R4-1) with a ‘BRIDGE DAMAGE CONTROL’ sign (TC2224) is used in accordance with Clause 4.6.6.4 MUTCD Part 2. The signs shall be installed on a highly visible fluorescent red / orange target board for increased conspicuity. The target board shall be the same shape as the traffic sign it highlights.
Advance warning of the change in speed limit shall be provided by installing a Speed Restriction
AHEAD (G9-79) sign at a minimum distance of 300 metres in advance of the start of the bridge speed restriction sign (TC2224) in accordance with section 5.1.6 of MUTCD Part 4.
On two-lane two-way roads, the TC2224 sign shall be duplicated on both sides of the road unless exceptional circumstances prevent installation on the right-hand side.
The minimum size of the sign shall be size B unless there are footway / verge width constraints that only permit size A signs.
The speed zone shall commence a minimum of 100 metres before the bridge on the approach side and extend to minimum of 100 metres on the departure side of the bridge to encourage compliance with the reduced speed limit by drivers. Complying with the minimum length requirements of
MUTCD Part 4 Table 4.1 is not required.
In some instances it may be necessary to install pavement markings, for example, Wide Centre Line
Treatment (WCLT), to narrow the lane width and influence the speed changes. If the WCLT is required it shall be installed in accordance with TN155 Wide Centre Line Treatment – Interim Advice .
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4 Speed zoning and speed limit review
4.2 Procedure for establishing speed zones
4.2.6 Crash history
4.2.6-1 Advisory notes on analysis of crash data
1 Purpose
This document provides guidance in implementing the provisions of Section 4.2.6 MUTCD
Part 4: Speed Controls.
2 Background
The sixth issue of MUTCD Part 4, issued on 18th November, 2013, included a revised Appendix E.
Appendix E provides advice on calculating the crash rate of the road section being reviewed. Road sections with high crash rates should be subjected to a safety review.
This document provides clarification of the content of Appendix E. It describes more clearly the critical crash rate and how this is derived. It also provides advice on the critical crash rates given by the
Traffic Accident Remedial Program (TARP) system for Transport and Main Roads (TMR) users.
Appendix E will be updated to reflect the content of this advice note in the next revision of MUTCD
Part 4. In the meantime all users of Part 4 are advised to follow the content of this document and to refer to it, if necessary, when using Appendix E.
3 Changes to Appendix E in Sixth Issue
There were three main changes to Appendix E in the sixth issue, released on 18th November, 2013.
1. The unit for crash risk was changed from crash cost to a standardised crash risk unit. This change avoids the need to revise the crash cost values in MUTCD every year simply to reflect annual inflation rates. The crash risk unit still takes into account of the number and severity of crashes at a particular site. Table E1 provides the values to be used in calculating crash rates for speed limit reviews.
2. Crash rates are to be calculated using casualty crashes only. Previously they were calculated using all reported crashes including ‘Property Damage Only’ (PDO) crashes. However, most
PDO crashes occurring after 31st December, 2010 will not be recorded. Therefore crash rates should be calculated for casualty crashes only; that is Fatal, Hospitalisation, Medical
Treatment and Minor Injury crashes.
3. Tables E2 to E5 were introduced so that network wide average and critical crash rates for different road types in Queensland are available for comparison with the average crash rate for the subject section. Before these tables were included, network wide average and critical crash rates had to be calculated by the practitioner. This change reduces the work in undertaking a speed limit review and improves consistency in the speed limit review process in Queensland. The average crash rates for the subject section are still to be calculated by the practitioner manually or using QLIMITS. A numerical example is presented in Section 6 to explain how it is done manually.
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4 Critical crash rate
In Appendix E on page 4-56 there is an explanation of part of the formula used to calculate the critical crash rate. It says:
‘The value of 1.645 in the above formula is a constant related to the normal probability density function. The value of 1.645 has been chosen as the upper 5% of the tail. This probability is chosen such that there is a small likelihood (e.g. 5%) that a normal site is judged as hazardous’.
This paragraph may be misleading some users into thinking that the critical crash rate represents the
95th percentile crash rate and that only the most hazardous 5 percent of sites will exceed the critical crash rate. This is not the case. The critical crash rate is the expected average crash rate plus some measures of variability.
Sites are considered potentially hazardous if they have actual crash rate that is higher than critical.
In calculating the population average, our confidence of determining the average value from a sample of road sections depends on the number of samples. The greater the sample size the greater our confidence. So in calculating the critical crash rate, we determine a value that we have a 95 percent confidence level is not less than the actual average crash rate for all sites on the road network.
This helps to explain and understand why, in many cases, the critical crash rates in tables E4 and E5 are only slightly higher than the corresponding average crash rates quoted in tables E2 and E3. For example, for a 100 km/h trunk collector in a rural area carrying 15,000 vehicles per day, tables E3 and
E5 give the following values:
•
Average casualty crash rate: 5,690,000 ERU per 108 VKT
•
Critical casualty crash rate: 5,870,000 ERU per 108 VKT.
The critical crash rate is slightly higher than the average crash rate. This is consistent with the correct definition above of the critical crash rate.
5 TARP values
For departmental staff there is access to actual, average and critical crash rates through the TARP analysis. This can be found in ARMIS, Chartview and Roadcrash2. However, while the calculations of these values use the same methodology, the formula is not applied in the same way as in Appendix E.
In the TARP analysis the road categories (model road state) and speed bands are different to the categories in Appendix E. Also, the crash rates are calculated using crash costs that currently include
PDO crashes also. This is not consistent with the approach taken in Appendix E. It is essential that, for the purposes of a speed limit review, all practitioners calculate the actual crash rate for the road section being reviewed using the methodology in Appendix E and do not rely on values from other sources.
6 Numerical example
The following numerical example is presented to show the calculation of the Average Crash Rate for a road section.
The section of road for which a speed limit review is being undertaken has the following data required for estimating crash rate:
•
Average Annual Daily Traffic (AADT): 2,000 veh/day
• length of section: 10 km
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• existing posted speed: 80 km/h.
Crash data for five years and corresponding risk scores are given below:
DCA Code
201, 501
305-307, 504
207, 304
609, 905
Description
Head on
Lane change
U-turn
Hit animal
No of crashes
1
4
1
2
Average annual crash rate for the above section of road is calculated as below:
R
= t
20
∑
=
1
C t
* A t
M
* 10
4
= [192*0.2+27*0.8+47*0.2+31*0.4)*104] / (10*2,000*365)
Risk Score
192
27
47
31
= (81.8*104) / (0.073*108)
= 1,120.5*104 / 108 = 1,120.5*104 ERUs per 108 VKT
As this is an arterial road in a rural area, the critical crash rate, taken from Table E5 in Appendix E, is
1,098.7*10 4 ERUs per 10 8 VKT. The actual crash rate is higher than the critical crash rate. Therefore the road section has a high crash rate and a safety review should be undertaken.
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4.5 Length of speed zones
4.5.2 Speed zones approaching intersections
4.5.2-1 Speed reduction on approaches to controlled high speed rural intersections
1 Purpose
The purpose of this document is to provide guidance for implementing Section 3.6 of MUTCD
Part 4: Speed Controls.
2 Background
Speed zones with speed limits reduced as per Section 3.6 of MUTCD Part 4 may be implemented on approaches to intersections, which have either a high crash history or high potential of crash risk.
Pavement bars can be used on side roads of such intersections to assist with greater compliance of the reduced speed.
Pavement bars are raised blocks that may be used to augment painted islands and painted median strips to discourage, but not prohibit, traffic movements across the islands or median strips.
The objectives of these pavement bars are to:
• act as a visual and tactile cue that different driving conditions apply
• discourage through traffic
• reduce speed and provide a traffic calming function
• improve safety.
Pavement bars should be 200 mm wide and 400 mm long. They shall have an approximate hemispherical cross-section with rounded ends.
Pavement bars shall be painted or otherwise coloured yellow and they shall be reflectorized.
Bars shall be arranged inclined to the direction of travel so as to increase motor cycle safety and minimize the possibility of loss of vehicular control if traversed.
Their application shall be limited to the following: a) Where the 85th percentile approach speed is less than 75 km/h, the height of the bar used shall be a maximum of 50 mm.
3 b) Where the 85th percentile approach speed exceeds 75 km/h pavement bars shall not be used.
Raised retro reflective pavement markers arranged in transverse rows shall be used instead
(see Clause 5.6.5.2(f) and Figure 5.25 of AS 1742.2 - 2009).
Speed zones approaching intersections
Reduced speed limits may be applied on approaches to intersections with speed limits of 80 km/h or greater, which have either a high crash rate history or high potential risk (determined by road safety review, and Section 4.2.6 of MUTCD Part 4) as follows:
• controlled approach - speed limit may be reduced to 60 km/h
• uncontrolled approach - the speed limit may be reduced by up to 30 km/h.
To ensure compliance with the reduced speed limit the following is required:
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• at least "B" sized Speed Restriction signs shall be installed
• signs shall be duplicated on both sides of the roadway
• signs shall have a fluorescent red/orange target board
• the length of the speed zone shall not exceed 300 m, and
•
Speed limit AHEAD signs shall be used in accordance with Clause 5.1.6 of MUTCD, and
• consideration to additional warning signs on the approaches has been given.
4 Application – pavement bars serving traffic controlling function
Typical arrangements of pavement bars are as follows: a) Control of turning movements at intersections (see Figure 4.5.2-A).
Figure 4.5.2-A – Pavement bars for control of turning movements at intersection b) Lane control (see Figure 4.5.2-B).
Figure 4.5.2-B – Pavement bars for lane control c) Supplementing barrier lines where frequent and hazardous infringements occur, except on substandard curves. d) Replacing raised islands where these are undesirable or not considered effective because of the absence of street light or restricted pavement width. e) Replacing a raised island where, but for limitation on minimum size, it would otherwise be used. f) Approach treatment to median or other central obstruction (see Figure 4.5.2-C).
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Figure 4.5.2-C – Pavement bars at a median approach g) Replacing a narrow median (see Figure 4.5.2-D).
Figure 4.5.2-D – Pavement bars used as a median h) Islands traversable by over-dimension vehicles.
Pavement bars shall not be installed on a two-way roadway less than 6.8 m in width, or on substandard curves.
Installations of pavement bars should be outlined with single unbroken lines. If the installation is in the form of a median dividing opposing traffic, the outline markings may consist of barrier lines.
Appropriate road lighting in accordance with Transport and Main Roads Specifications shall be considered.
5 Application – pavement bars serving traffic calming function
Where pavement bars are implemented to serve solely a traffic calming function, adequate measures must be implemented to ensure pedestrians do not perceive and use it as a zebra crossing.
These pavement bars must:
• not be located on a pedestrian desire line
• not include a pram ramp or pedestrian refuge
• have the pedestrian footpath physically separated by pedestrian barriers (use fences or landscaping as appropriate)
• include appropriate warning signs together with advisory speed signs as necessary to warn road users, and
• not have any perception of pedestrian priority.
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Where pavement bars cannot meet these requirements, they must be treated as though they serve both traffic calming and a pedestrian crossing function in accordance with Transport and Main Roads
Specifications.
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4.5.3 Speed zones at high crash sections
4.5.3-1 Speed limit reductions in high crash zones
1 Purpose
The purpose of this section is to provide guidance for implementing Section 4.5.3 of MUTCD
Part 4: Speed Controls. It reinforces the criteria for speed limit reduction set out in the MUTCD, describes the process of approval, zoning and signage requirements and provides advice on evaluation.
2 Background
The MUTCD allows speed limits to be reduced on roads where a road section has a high crash rate and a road safety review has been conducted. This document describes the measures that are required to be implemented under the circumstances when there will be a delay in the commencement of the required works to address the road safety deficiency.
If there are no feasible remedial treatments to address the safety problems identified by a safety review, the MUTCD suggests the following: a) if the speed limit review has suggested a higher speed limit, retain the existing speed limit b) discuss with the Queensland Police Service the potential for increased enforcement, and c) reduce the existing speed limit to attempt to reduce the number and severity of crashes.
Historically, this provision within Part 4 of the MUTCD has not been widely exercised. Due to the imperative of reducing road trauma in Queensland it is necessary to consider a more pro-active application of speed zoning.
3 Criteria for speed limit reduction
Following a speed limit review, a reduction in speed limit may be considered if the casualty crash rate for the road section is significantly higher than the critical crash rate and: a) remedial measures recommended through a road safety review cannot be implemented in a reasonable time, or b) there are no feasible remedial treatments to address the road safety problem.
Refer Section 1.6 Glossary of Terms, Section E2 of Appendix E for the definition of high crash rates.
4 Speed limit
A speed zone that a majority of motorists perceive to be credible will ensure maximum levels of voluntary compliance by motorists and offer maximum road safety benefits by reducing speed disparities and encouraging uniform travel speeds. Therefore, where the speed limit is reduced it may be necessary to change the speed environment to encourage compliance with the reduced speed limit.
The use of wide centreline marking to reduce the width of through lanes should be considered. Where the road geometry restricts vehicle speeds, the guidelines in Section 4.2.4 of Part 4 of the MUTCD should be applied.
To ensure drivers are able to differentiate between the speed environment in the reduced speed zones and the speed environment in a regular speed zone, specific signage shall be installed to warn
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Part 4: Speed Controls drivers that they are entering a speed zone where the speed limit has been reduced due the safety performance of the section of road.
These signs must be installed in accordance with the signage requirements given below.
5 Speed zone signage
The Speed Restriction sign TC1797 at the start of the speed zone shall be a minimum "B" size (refer
Table 4.5.3-A).
Speed Restriction sign TC1797, including all repeater signs, will be on high visual impact (red/orange) target board.
In some instances it may be necessary to supplement the Speed Restriction sign TC1797 at the start of the speed zone with pavement markings (numerals).
Advance warning of the change in speed limit shall be provided by installing a Speed Restriction
AHEAD (G9-79) sign a minimum distance of 300 metres in advance of the start of the speed zone. At the start of the speed zone and at regular intervals, sign TC1559 should also be installed to inform motorists of the reason for the reduced speed limit.
On two lane two way roads, all signs shall be installed on the left hand side of the roadway facing traffic in the direction of travel. On divided roads where the width of the median permits, signs shall be duplicated on the right hand side in the median. Where there are intersections and junctions within the speed zone that have high traffic volumes, repeater speed limit signs shall be spaced so that they are installed close to the intersection for the benefit of turning traffic.
Table 4.5.3-A – Sign size and location
Speed limit
Size of speed limit AHEAD (G9-79) sign
Size of TC1797 sign at start of speed zone
Size of signs on on-ramps
Size of repeater speed limit signs
Location of first repeater sign within speed zone
Location of subsequent repeater signs
Equal to or greater than 70 km/h
A typical signage treatment at high crash zone is shown in Figure 4.5.3.
6 Lengths of speed zones
B
B
B
B
300 m
1 km
In order to achieve compliance and to avoid frequent changes in speed limits, the minimum length of speed zones where speed limits have been reduced shall meet the requirements given in
Table 4.5.3-B.
Table 4.5.3-B – Length of speed zones
Speed limit after reduction (km/h)
90
80, 70
Minimum length of speed zone (km)
5
2
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7 Approval of speed reductions
MUTCD Part 4 approval process shall apply.
8 Evaluation
Speed data shall be collected prior to implementation and analysed to that of post implementation data collected at six monthly intervals to ensure the effectiveness of the speed reduction measure implemented in accordance with this Supplement.
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Figure 4.5.3 – Typical signage treatment
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4.5.4 50 km/h speed zones on state controlled roads through rural towns
4.5.4-1 Guidelines for the application of signed 50 km/hr speed limit on state controlled roads through rural towns
1 Purpose
The purpose of this section is to provide guidance for implementing Section 4.5.4 of MUTCD
Part 4: Speed Controls. It also assists in:
• identifying circumstances where a 50 km/h speed zones could be applied on state controlled roads through rural towns, and
• establishing the minimum length and signing requirements for such speed zones.
2 Background
State controlled roads through rural towns are generally signed at 60 km/h. However, the increased pedestrian activity and the speed environment through some rural towns suggest that a speed limit lower than 60 km/h should be established to increase the safety for pedestrians while still maintaining mobility for through traffic and amenity for adjacent land users.
3 Minimum requirements
A 50 km/h speed limit may be applied to state controlled roads through rural towns with strip shopping centres, commercial areas and activity centres. This reduced speed limit should only be considered for roads with an existing speed limit of 60 km/h. Roads considered for the 50 km/h speed limit shall satisfy the following criteria:
• the speed environment through the town supports a speed limit of 50 km/h
• there is increased pedestrian activity throughout the length of the speed zone, or
• there is a history of pedestrian related crashes which cannot be addressed by other engineering treatment.
To encourage maximum voluntary compliance with the 50 km/h speed limit, it is essential that the speed environment is compatible with the speed limit. Where the speed environment is not compatible with the speed limit, the speed environment through the town shall be physically changed. The following physical treatments should be considered to change the speed environment through the town:
• provide narrow traffic lanes for through traffic
• provide kerbside parking and/or centre parking
• installation of kerb extensions at the start of the speed zone and within the speed zone
• provide adequate landscaping
• installing threshold treatments to identify the start of the speed zone.
Strip shopping centres and commercial areas which may be considered for application of a 50 km/h speed limit are those that have regularly/closely spaced premises along a road. This would generally occur where the traffic carrying road passes through the main shopping centre and/or commercial area of a town that is through the town centre.
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Where there are only scattered/isolated shopping/commercial premises along a state controlled road, a 50 km/h speed limit should not be applicable.
4 Signing requirements
Where a 50 km/h speed limit is applied to state controlled roads through rural towns the following shall apply:
•
"C" size 50 km/h Speed Restriction (R4-1) signs shall be installed on the left hand side of the carriageway at the start of the speed zone
• consideration is given to supplementary pavement markings
• the Speed Limit AHEAD (G9-79) sign shall be installed 300 m to 500 m in advance of the start of the 50 km/h speed zone in accordance with the requirements of Part 4 of the MUTCD.
5 Length of speed zones
The minimum length for a 50 km/h speed zone should comply with the requirements of Table 4.1 of
Part 4 of the MUTCD. Accordingly, wherever possible, a minimum length of 500 m should apply to
50 km/h speed zones on roads through strip shopping centres and commercial areas.
However, if the length of a strip shopping or commercial area is less than 500 m, the 50 km/h speed zone may be shortened accordingly. Permitting the use of 50 km/h speed zones shorter than 500 m is intended to encourage maximum levels of voluntary compliance by motorists who are unlikely to comply with the lower speed limit unless the speed environment is compatible with the speed limit.
The absolute minimum length shall be 200 m.
Figures 4.5.4-A and 4.5.4-B show examples of the preferred sites for the application of a 50 km/h speed zone in rural towns.
Figure 4.5.4-A – Preferred application of a 50 km/h speed zone for a shopping or commercial area in rural towns – Example 1
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Figure 4.5.4-B – Preferred application of a 50 km/h speed zone for a shopping or commercial area in rural towns – Example 2
6 Alternative treatment for small towns
Where the following exists, it may be appropriate to extend the 50 km/h speed zone to include the full length of the road within the town limits:
• there are no other 60 km/h speed zones within the town
• the shopping or commercial area extends to within 300 m of the town limits, and
• the 50 km/h speed zone will be at least 500 m long.
Figure 4.5.4-C shows the application example of a 50 km/h speed zone for small towns.
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Figure 4.5.4-C – Alternative application of a 50 km/h speed zone for a shopping/commercial area in small rural towns only
7 Traffic volume considerations
Traffic volume is generally not a criterion for determining the suitability of a 50 km/h speed limit through a town. However, on lower volume roads through small towns in more remote areas, a significant percentage of the vehicles will be using the road to access the town facilities. That is, the road will be providing more of a local traffic function. In such cases, a 50 km/h speed limit could be considered if it does not adversely affect the performance of the state road network and the road environment could be altered.
8 Circumstances where a 50 km/h speed limit should not be applied
Circumstances in which a 50 km/h speed limit would generally not be appropriate include:
• roads with an existing speed limit greater than 60 km/h
• roads with an existing speed limit less than 40 km/h
• roads with isolated shops or commercial properties
• where the speed environment is not compatible with the 50 km/h speed environment, and
• where shops and commercial properties are located on service roads and there is no parking on the through route.
9 Approval requirements
Usual MUTCD Part 4 approval process shall apply.
10 Illustrations
Photographs 1, 2, 3, 4 and 5 illustrate typical rural town environment where a 50 km/h speed limit sign could be applied in accordance with this document (see Section 3: Application of criteria based speed limits).
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Photographs 7 and 9 are typical examples where a 50 km/h speed limit should be supported after the change in road environment by implementing additional measures for traffic calming (see Section 3:
Application of criteria based speed limits).
Photographs 6 and 8 show typical example sections of a traffic carrying road through a town where a
50 km/h speed limit would not be appropriate (see Section 3: Application of criteria based speed limits).
Note: These illustrations are for guidance only. Applicability of a reduced speed limit should be assessed against the criteria of this document (see Section 3: Application of criteria based speed limits).
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5 Speed limit signs
5.2 Sign application
5.2-1 Placement of speed limit awareness signs on local streets
1 Purpose
The purpose of this section is to provide guidance for implementing Section 5.2 of MUTCD
Part 4: Speed Controls. It defines the requirements for installing speed limit awareness signs on wheelie bins in local streets with a default speed of 50 km/h.
2 Background
The speed of vehicles in local streets is often raised as a concern by communities. An initiative to combat speeding on local streets is the use of placing speed limit awareness signs on wheelie bins on local streets. This initiative was trialled successfully by Ipswich City Council in 2006.
50 km/h is the default general urban speed limit and generally applies to streets with a local access function. These streets are not sign posted as the speed limit applies by default.
The 50 km/h speed limit for local streets was introduced in South East Queensland in 1999 and to regional Queensland in 2003. An extensive education campaign was conducted when the lower speed limit was implemented.
Some councils have advised that residents often complain of drivers speeding on their local street.
Studies have shown that there is a greater compliance with the speed limit if the speed environment is compatible with the speed limit.
Local streets which have long unbroken sections and wide pavements often have a lower level of compliance with the speed limit. In such cases, engineering treatment, such as changing priority at intersections, kerb extensions, installing chicanes or threshold treatments to change the speed environment should be considered.
In situations where other measures to reduce the speed of vehicles have previously been implemented without success and the speed of vehicles in local streets is raised as a concern by communities, the road authority may consider implementation of speed limit awareness signs on wheelie bins.
3 Installation criteria
The following criteria apply to the installation of speed awareness signs on wheelie bins: a) signs shall only be installed on local streets with a speed limit of 50 km/h b) signs should only be used on streets that have an 85% percentile speed in the range of
58 km/h to 65 km/h, and c) the Annual Average Daily Traffic (AADT) on the street should not exceed 1000 vehicles per day.
4 Signage requirements
Where the above criteria are met, the TC1638 sign is approved for use on wheelie bins as a speed limit awareness sign. Installation of this sign is to be in accordance with the approved condition on
TC1638 without variation.
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5 Sign installation
The speed limit awareness signs are intended to remind drivers of the speed limit. It is not necessary to install signs on every wheelie bin in the street.
It is essential that the signs are not overused as this will reduce their effectiveness. It is recommended that the signs be installed on wheelie bins in selected local streets in a precinct that will have the largest impact on speed awareness. Where approved, following requirements apply for sign installation: a) all signs shall be installed by a person authorised by the council to install official traffic signs b) only one sign shall be installed per wheelie bin c) the sign shall be placed on the side of the bin facing oncoming traffic
6 d) signs shall not be installed on wheelie bins of houses that are at a junction or intersection e) signs shall not be installed on wheelie bins of houses that are within a school zone or within a speed zone of less than 50 km/h.
Other considerations
If road works are being conducted on a local street with speed limit awareness signs and the speed limit has been reduced, it is the responsibility of the authority conducting the road works to minimise confusion of the speed limit.
To ensure that motorists are aware of the reduced roadwork speed limit, it may be necessary to install additional regulatory speed limit signs with road works signs along the length of the roadwork.
7 Monitoring and evaluation
Speed surveys should be conducted prior to and after the use of the signs to monitor performance and effectiveness.
If after a period of six months of installation there is only minimal impact on driver compliance with the speed limit other engineering solutions should be considered.
Figure 5.2-A – TC1638: Wheelie bin – speed reminder sticker
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Figure 5.2-B – TC1638: Wheelie bin – speed reminder sticker application
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5.2.6 Motorway ramp zones
5.2.6-1 Speed limit signing on ramps
1 Purpose
The purpose of this section is to provide guidance for implementing Section 5.2.6 of Manual of
Uniform Traffic Control Devices (MUTCD) Part 4: Speed Controls. It aims to clarify the speed limit to motorists at interchanges where there is confusion between ramp speed limits and through road speed limits.
2 Background
At certain installations, speed limit signing occurs on both sides of a ramp as well as the through road.
For example, an off-ramp speed limit may be 60 km/h while the through road may be 100 km/h. In this case the through traffic sees both signs side by side if the ramp is at a similar level to the through road.
Although signs on the right-hand side perform an important function (particularly on multilane exits), the action to remove any confusion has been to remove the speed limit sign from the right-hand side.
Figure 5.2.6-A – Typical speed limit signing on ramps (derived from Figure 3.1, Part 2: MUTCD)
3 Accepted practice
Speed limit signs should only be provided on the left-hand side of on and off ramps.
Where there is a requirement to duplicate speed signs on the right-hand side (e.g. on multi-lane ramps) the supplementary sign plate (TC1331) should be provided on both signs on the ramp.
Any existing speed limit signs provided on the right-hand side should be relocated to the left-hand side and in situations where these signs are duplicated, should be removed from the right-hand side.
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Figure 5.2.6-A shows the typical speed limit signing on ramps. Figure 5.2.6-B provides details of supplementary sign plate.
Figure 5.2.6-B – TC1331: Details of supplementary sign plate
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