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- and poor signing will make things worse
'Poor road design' means a design that unfamiliar road users will have trouble using or following in the way the designer intended.
Typical problems are unusual road layouts, misleading layouts, unexplained options and not enough time between decisions points.
'Poor signing' means a signing scheme that takes insufficient account of the MUTCD (AS 1742) and is designed with little understanding of how road users will respond.
A. Poor Road Design that Signs Can't Fix
Here, on the right, is a poor road design (in western China), where the exit splits immediately into two different ramps that are out of view to approaching drivers until they are on the exit. An unfamiliar driver has no time after exiting, to decide which ramp to take. There is insufficient time to make the decision.
If such a design was built in Australia, no amount of advance signing could be designed to explain to drivers how to safely negotiate the layout. (Also note the absence of collapsible crash cushions if you can't choose which ramp to use). A better design would provide an extra parallel exit lane for at least 200 m before this point, so the decision to exit is separated in time from the decision about which route to take.
It needn't be a complex freeway. Below are two examples where a divided road (two lanes each way) changes to an undivided two-way road with one lane each way. If a driver makes a mistake about how long they need to overtake, they end up driving into the section of undivided road with oncoming traffic. This will lead to head-on crashes. Signs to get traffic into one lane will not fix this problem: the design should physically force traffic into a single file before the kerbed median ends.
A hazardous exit - too complex for unfamiliar drivers
Overtaking traffic on the dual carriageway can drive straight into the oncoming lane (UK)
No amount of signs (or paint) can prevent head-on crashes in this situation (Victoria)
B. Road Designs that Rely Heavily on the Signs
Many designs rely on clear, unambiguous signing. Here is an example in Carnegie, Melbourne: two closely-spaced left turn lanes. They are separated, but the distance between them is minimal. The first left turn goes into a car park and the second one goes into the arterial cross road (Koornang Road) at the traffic signals.
The sign on the island, pointing to Koornang Road worked adequately before the car park was built. But with two left turn lanes, the sign is ambiguous: does it point into the first or second turning lane? Once the car park opened, many complaints were made by drivers who got in the left turn lane for the car park, thinking that lane led to Koornang Road.
Rob Morgan fixed this problem for the local Council. As a result of this example - and seeing it elsewhere - Rob then developed a standard signing arrangement for closely- spaced turning lanes (left or right hand) and this is now in the MUTCD at Clause 2.4.8 of AS 1742 Part 15 (2019), and it is illustrated in Figures 2.8 and 2.13 of that Standard.
C. Why Project Managers Shouldn't Be Making Traffic Design Decisions
Get Project Delivery Engineers to Deliver a Project, BUT Get Traffic Engineers to Approve the Traffic Elements
It makes some sense that the main objective of road project delivery engineers is to get the project built (on time and within budget): the plan says this, so we build it like this. This is probably OK if the road design is done by others with enough expertise in traffic engineering and signs and lines (though see Basic Rules 2. and 3. below). Where it can - and does - go seriously wrong is when the design is done for a project delivery office and they do the final sign-off without adequate traffic engineering or road safety engineering scrutiny. Project delivery engineers typically have loads of experience about how to build things, but no idea about what an effective traffic layout looks like, once it's completed.
So why are government organisational arrangements like a separate Major Road Projects Victoria established, where design approval is made within the project delivery organisation?
Chandler Highway Bridge Project - an Example
Over the past few years the old two lane Chandler Highway bridge over the Yarra River has been replaced by a six lane divided road (including a new six lane divided bridge) between the Eastern Freeway interchange and Heidelberg Road. Over the Eastern Freeway, the Chandler Highway bridges are two lanes each way, creating a potential squeeze point southbound, at the end of the new works. But before the freeway bridges, the median is wide and there is a left-hand entry ramp onto the freeway that takes about one third of the southbound traffic. The obvious design solution is to widen into the median to retain three lanes, with the left lane being exclusively for the freeway entry ramp. This way, there is no squeeze point.
When the final project design included the squeeze point, with three lanes reducing to two on the before the freeway entry ramp (and on the approach to a set of traffic signals), I proposed to the Project Office that they widen into the median and avoid the squeeze (see sketch at right).
This was rejected. The primary reason, I was told, was that the ability of the 'Existing Bridge' before the entry ramp (see sketch) to carry the load of an extra lane of traffic was unknown. It was not that it was too weak; it was that it had not been investigated and was unknown. This bridge is over a ramp that was never built. It could easily be strengthened or given additional support. So a $110 million project to ease congestion ends at a squeeze point with road safety implications that could have been avoided if the project scope had been adequately considered traffic and safety.
Now consider the traffic signs. After my success with Item B (above) at Carnegie, I brought to the attention of the Project Office a similar problem in Heidelberg Road, on the approach to the Chandler Highway: this time with two closely spaced right turns. A very poorly designed right turn lane into Coate Avenue had been created in the 1980s. Here was an opportunity to make that design safer (insert a median to the right of the right turn lane, not to its left !) AND make the direction signs to the new Chandler Highway unambiguous. My sketch proposal is here > >
What happened? Absolutely nothing. It's one thing to end up with the old arrangement at Carnegie, because no one thought about it. It is an entirely different situation where the Project Office is told of the problem and its solution and decides to ignore that advice.
So, the signs that were installed as part of this project and which now mislead drivers on Heidelberg Road are shown below. Compare them with what is now in AS 1742 Part 15, following my experience at Carnegie (shown in the diagram after the photos).
The advance direction sign, pointing to the next right turn. The 'HR' type right turn arrow should be 'ERS type' - see Table 1.4 in AS 1742 Part 15 (2019)
The big G2-1 sign for right turns into Chandler Highway / Kew / M3 directs drivers into the right turn lane to Coates Avenue. Old posts obstruct the sign. Who cares?
How the location in the right hand photo (above) should have been signed. This is a modified extract from Figure 2.13 in AS 1742 Part 15 (2019). Clause 2.4.8 and Figure 2.8 also describe how to sign this arrangement for closely spaced left turns or right turns. It looks similar to my 2016 advice to the Project Office.
D. Signs Pulled Out of a Hat (No reference to the MUTCD, AS 1742)
Here is a signs and line marking plan at the start/end of a major road duplication on the urban fringe. Westbound, the old road drops down to a poorly aligned creek crossing.
The numbers and notes are from Rob Morgan's road safety audit of the plan. Here are just a few of the issues Rob identified (Clause references below are to AS 1742 Part 2):
8. There was no signing at all for the westbound lane drop (Clause 4.7.2 applies)
9. Ford and Floodway are two different conditions: you can't sign for both (Clause 4.10.6). The location of these signs is too close to the hazard (Clause D2.2). No depth indicators were included (Clause 4.10.6). Two warning signs must not be put on the same post (Clause D2.2). Bicycle Lane signs are not needed by the Road Rules: they add to clutter. Their removal allows the correct 'Floodways' signing to be installed.
12. The CREST sign is not warranted (Clause 4.5.4.1).
13. The Traffic Signals Ahead warning sign is not warranted (Clause 6.1.2(g))
The above signing scheme was not designed by a small engineering outfit; it was designed by one of Australia's biggest engineering consulting companies. Yet none of the four engineering professionals named on the Signs and Linemarking Plan (for drafting, checking, etc.) claims any experience or expertise with traffic signs. Interestingly, one of the most senior engineers in the company has been one of the few professionals to support the mandatory licensing of professional engineers in Victoria (RPEV). This example illustrates that the main problem around the integrity of professional engineers is not that non-engineers are claiming to be professional engineers; it is that professional engineers are acting outside their own areas of expertise. Once RPEV registration is mandatory, any new signing scheme like this will deserve to be brought to the attention of the Registrar: it is quite evident that the engineers involved have breached the professional engineers' Code of Conduct by acting outside their area of engineering expertise. Which brings me to my three Basic Signing Rules for Road Designers . . .
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Basic Rules About Traffic Signs that Road Designers Need to Know
Basic Rules About Traffic Signs that Road Designers Need to Know
1. ACT EARLY
At the Concept Design Stage and Preliminary Design Stage,
you need to know what types of signs will be needed and where they will be located
1. ACT EARLY
At the Concept Design Stage and Preliminary Design Stage,
you need to know what types of signs will be needed and where they will be located
Signs are typically considered near the end of the design process (at 'Detailed Design') for road and traffic projects. But that's too late if:
- you haven't left enough space for the signs and their supports, or
- the road design is poor and the signs will be too complicated for drivers to understand
These signs are in the wrong place. The Stud Road EXIT sign should be at the start of the exit taper, as the approach is around a left-hand curve. The big sign should be located after the exit, so the curved arrow to Police Road is not confused with this exit. These two requirements had been in AS 1742.15 for years before this project was designed
The Stud Road EXIT sign can be relocated, but the big sign can't be easily moved: it requires a major support structure in the median. Also, a new location may conflict with the new overhead speed limit signs.
These issues need to be thought through at the early design stages, so sign structures can be sited correctly.
This site is an example of not getting the right people with the right experience involved early enough (also see my Rules 2 and 3 below). When this freeway was originally designed (in the 1960s), exit signs were installed halfway along the painted exit gore markings. But that changed with AS 1742.15 in 2007, which required the exit sign to be placed at the start of the exit taper. Any additional signs for the next exit were required to be installed beyond this first exit. (For example, see Figure 3.12 in AS 1742.15 (2007)). It appears that no one involved with this freeway widening project appreciated this, and the new gantry was located where the old one was. This is despite Eastlink having been built and the signing in this area consequently being more complicated. The unfathomable thing is that the old gantry was demolished in 2017 and new ones could have been positioned anywhere.
(There are also serious problems with how 'POLICE RD' and 'M3 Ringwood' are signed: does the left lane only go to Police Road? The 2019 edition of AS 1742.15 has resolved this problem).
Basic Rules About Traffic Signs that Road Designers Need to Know
Basic Rules About Traffic Signs that Road Designers Need to Know
2. TRAFFIC SIGNS ARE A SPECIFIC EXPERTISE
You wouldn't leave the design of a bridge to an engineer with no structural expertise.
Why imagine an engineer with no signing experience can design a traffic signing scheme?
2. TRAFFIC SIGNS ARE A SPECIFIC EXPERTISE
You wouldn't leave the design of a bridge to an engineer with no structural expertise.
Why imagine an engineer with no signing experience can design a traffic signing scheme?
Traffic signing fundamentals are contained in the MUTCD, AS 1742. There are 14 Parts to AS 1742, so there are a lot of fundamentals!
Designing effective signing schemes also requires an understanding of 'human factors' or road user behaviour- how will drivers respond to the signs you install?
The impacts of poor signing can be minor or severe: drivers ignore the signs (as they're unreliable); drivers make wrong decisions;
drivers miss decisions; drivers miss information. As a result they can be distracted and take actions that lead to collisions.
Signing expertise and experience costs money. But so too do road crashes and patch-up works. So the initial use of the right expertise is cost-effective.
Who in their right mind would imagine this advance sign is an effective way to get this information across to drivers? (The 'Fun Facts' below may help answer this question).
Here are some obvious issues:
The sign is on the wrong side of a wide road (out of the field of view; lettering too small for the offset).
The sign is too close to the inter-section (not enough time to respond).
The sign face is too complicated to separate the information (drivers will make mistakes).
It's a multi-million dollar project. Why skimp on the quantity and size of signs and have the signing scheme designed by someone without the right expertise?
Fun Facts About This Project:
This is at the Duncans Road Interchange on the M1 Princes Freeway, on the west side of Melbourne. It's part of the Western Roads Upgrade. According to https://bigbuild.vic.gov.au/projects/western-roads-upgrade, the Western Roads Upgrade:
is a $1.8 billion investment to improve roads in the western suburbs
includes a 20-year maintenance contract, which guarantees the ongoing care of 260 km of road from Footscray to Werribee
is being delivered through a Public Private Partnership (PPP) between the Victorian Government and project consortium, Netflow.
The Netflow consortium (https://netflowjv.com.au/projects/western-roads-upgrade/) advise that 'WBHO Infrastructure [act] as design and construction lead'.
On 27th December 2020 the Sunday Age reported 'the head contractor on the [Western Roads Upgrade] project, South-African headquartered and Perth-based WBHO, has reported $133 million in losses after it admitted to under-bidding to win the work, and its executive chairman, Louwtjie Nel, conceded the project was the company’s “biggest error in 50 years” '.
Major Road Projects Victoria (https://roadprojects.vic.gov.au/projects/westernroadsupgrade/duncans-road-interchange) advises that the benefits of this Duncans Road Interchange project include 'reduced congestion and increased safety by improving the busy K Road intersection'.
Basic Rules About Traffic Signs that Road Designers Need to Know
Basic Rules About Traffic Signs that Road Designers Need to Know
3. VERY FEW TRAFFIC ENGINEERS
AND VERY FEW ROAD SAFETY AUDITORS
HAVE AN IN-DEPTH UNDERSTANDING OF TRAFFIC SIGNS
Just because a scheme has been 'road safety audited',
that doesn't mean the traffic signs are appropriate or effective.
3. VERY FEW TRAFFIC ENGINEERS
AND VERY FEW ROAD SAFETY AUDITORS
HAVE AN IN-DEPTH UNDERSTANDING OF TRAFFIC SIGNS
Just because a scheme has been 'road safety audited',
that doesn't mean the traffic signs are appropriate or effective.
FIRST ISSUE: Project delivery people are inclined to say a scheme 'has been road safety audited', as justification for accepting poor signing.
Typically, these people don't have the expertise and experience themselves and they don't appreciate what effective signing looks like.
SECOND ISSUE: There are a lot of big engineering consultancies that tell clients they can do anything (and they tend to believe their own publicity).
I know of not a single one of these big companies that has the expertise to design a signing scheme for any complex traffic arrangement.
There are also a lot of traffic engineers who are good at other aspects of traffic engineering, but lack fundamental skills about signs and lines
(for example, see Item 4 under The Oops! File > Ways I Can Help You, showing the obviously substandard signs at Melbourne Airport's T4 Terminal).
Here is a simple 12-page download (click on this underlined title) on what Rob Morgan sees as the ten most popular mis-uses of traffic signs and lines in Australia. It also provides advice on how to avoid these common mistakes and use the signs and lines correctly. This includes references to the particular clauses in AS 1742 - our Manual of Uniform Traffic Control Devices.
EXAMPLE 1: Northconnex in Sydney
This is the northern entry to the Northconnex motorway (and the M1) in Sydney, off Pennant Hills Road. The two-lane entry ramp curving to the left has been open for several years. The extra lane, exiting to the right (to Sydney and Canberra), was opened in early 2021. It was reported at the time that police had attended a number of crashes on this section of road soon after the right hand ramp opened. A concerned member of the public contacted me.
Firstly, this layout sits firmly in the 'poor road design' category. The main decision point (to exit right or not) is immediately after a location requiring concentration (a double lane right turn) and the decision point is out of view until the last moment. Part of the reason may be the limited space available and the reluctance to acquire extra land.
Access to this two lane ramp is via a right turn off Pennant Hills Rd (or the left turn slip lane in the photo - at least they get an extra sign).
Note that there is only one sign on this road, directing to Sydney & Canberra. It's 2/3 along the ramp. There is no other confirmation sign, or advance sign.
Northern entry off Pennant Hills Road onto the M1 and Northconnex (Image; Google Street View, 9/23)
This road design is actually worse than item 'A' above, in western China, because here drivers in the wrong lane (i.e. the left-hand lane in the above photo) have to cross another stream of traffic to reach the ramp they want to use. The most obvious signing need, to compensate for this poor road design, is to have enough signs to ensure that all drivers wishing to go to Sydney or Canberra are in the right-most lane on Pennant Hills Road, before they turn right onto the ramp. Being caught in the other right turn lane is likely to lead to a crash or a near miss.
Pennant Hills Road, ~120 m before the right turn
(Image: Google Street View, June 2024)
But here is the last sign on Pennant Hills Road that gives any advice about how to reach Sydney and Canberra (There is also one more overhead sign on the median, before the two right turn lanes develop). So the sign here is the only one giving advice about which lane to use.
This breaks a basic signing rule about repeating complex or critical information.
For many drivers, this sign may simply say that Sydney and Canberra are via the right turn.
The sign should also have four arrow shafts (not just two), as there are four lanes at this position. Are some drivers thinking that either of the right hand lanes will reach Sydney and Canberra? The sign is already too complex.
What is needed is signs at intervals on the median between here and the intersection advising 'Sydney Canberra RIGHT LANE' and a sign confirming 'Newcastle BOTH LANES'. Signs over each right turn lane is another option. But the median is too narrow to accommodate any signs or sign supports.
This scheme fails to provide drivers with the critical message: for Sydney & Canberra you must be in the right-hand lane.
Despite this glaring design deficiency - and the reported crashes - Northconnex responded to the concerned member of the public (in relation to another sign on the project) as follows (inter alia):
"All road signage for the project has been developed by the project designer and reviewed by the independent certifier and TfNSW. As the regulatory authority, TfNSW has designed all the large directional sign faces for the project and the signs that have been installed are consistent with the certified drawings. Furthermore an independent Road Safety Audit has been carried out on the project and this sign [on another ramp] was not raised as a concern by the Auditors.
So there!
EXAMPLE 2: North East Link in Melbourne
This example illustrates:
how important it is to consider at a very early stage, how a project will be signed (Rule 1), and
that a road safety audit, no matter how well it's done (and it was done well in this case) can miss significant items if the audit team's experience is limited in particular areas (Rules 2 and 3).
The yellow arrows on the diagram show where it is proposed to make 'Bulleen Road' a right hand exit off the freeway-to-freeway interchange ramp between the Eastern Freeway (eastbound) and the North East Link (NEL, northbound). Before this right hand exit, the NEL will have split off the Eastern Freeway with a dedicated left lane to the NEL and a second lane that splits between the two freeways.
Having a right-hand arterial exit off a freeway-to-freeway ramp is very poor road design. The NEL Project does not accept this, noting that such a layout is not prohibited by any Austroads guideline.
The other question is: How might this sequence of closely spaced left and right exits be effectively signed?
North East Link / Eastern Freeway / Bulleen Road interchange, looking to the north east
(Image by NELA, April 2018) with yellow arrows added by Rob Morgan.
A letter to the NEL Project by Rob Morgan in November 2019, describes how the proposed layout (known as the Reference Design) cannot be effectively signed: any signing for Bulleen Road at the diverge off the Eastern Freeway and in advance of that point will either be wrong, deficient, misleading, unreasonably complex or ambiguous.
This highlights how important it is to consider the details of direction signs at a very early stage on any complex project. The letter can be downloaded here. (It's a safe pdf).
The letter describes how the solution will need to be to either:
Make Bulleen Road a left-hand exit off the freeway-to-freeway ramp to NEL, with a braided ramp to reach the ramp terminal (i.e. replace the poor road design),
Make Bulleen Road a separate left-hand exit off the Eastern Freeway, an adequate distance after the exit to the NEL (i.e. replace the poor road design), or
Widen the approach on the Eastern Freeway from five lanes to six lanes (including two fully developed lanes to NEL) well before the interchange (i.e. improve the poor road design), so a right-hand exit off the NEL ramp can be effectively signed. Without this change, a right-hand exit cannot be signed.
Due to secrecy around this project (all involved have had to sign confidentiality agreements - see my North East Link webpages) I have no idea what the final design decision has been.
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