Unintended Consequences: Examining the Safety Risks of Wales's New 20mph Rule

With the recent implementation of the law setting 20 mph as the default urban speed limit in Wales, I assumed that many higher standard and main roads would still maintain a speed limit of 30 mph.

I have previously highlighted evidence suggesting that 20 mph limits can be effective on roads naturally suited for lower speeds, as setting limits slightly below engineering recommendations can enhance safety.  20 mph limits on specific sections of higher standard and main roads, like implementing part-time limits outside schools, can also be an option. However, it's crucial that these exceptions remain just that—exceptions—so that motorists take them seriously.

Regrettably, the regulations governing exemptions to the new rule are poorly thought out and far more restrictive than my initial expectations. If there are houses lining the road it has to be 20 even if the houses along the road are ribbon development.

The old guidelines stated "20mph speed limits should only be used for individual roads or for a small network of roads. Research indicates that 20mph speed limits should only be used where mean vehicle speeds are 24mph or below or where traffic calming measures are planned as part of the speed management strategy".
The new guidelines state "Decisions on exceptions should not be influenced by existing traffic speeds." Notice the lack of the word 'research' in the second one.


Local authorities are now compelled to include higher standard main roads without considering levels of compliance, traffic speeds or engineering recommendations.
This approach not only undermines the significance of speed limits but also calls into question the broader importance of adhering to the law. It is difficult to comprehend how including such high standard roads aligns with the goal of making exceeding the speed limit less socially acceptable.
People will are likely to see the limit as wrong, irrelevant or even vacuous, and that attitude will carry over to places where a 20mph limit is more justified.

Considering traffic speeds is a well-established practice in the decision-making process. If there's an academic study supporting the approach of completely ignoring them, I would appreciate anyone sharing the link in the comments. I've submitted a Freedom of Information (FOI) request to the Welsh government, specifically asking for evidence supporting this approach. However, their response stated that they 'do not have this information.'

Monmouthshire made the decision to lower the speed limit and subsequently imposed a 20mph restriction on the entire B4245 that passes through Magor, Rogiet, and Caldicot.
Both the sections through Rogiet and the Caldicot bypass showed levels of non-compliance of 99%!
The average speed is now 12mph over the limit and the 85th percentile speed is 39mph.
Despite this, only the bypass will have its speed limit raised back to 30 mph. Both roads appear more suited for 40 mph limits, and I believe the bypass was originally designed for 40mph.
Previously, both roads already had a 97% non-compliance rate with the 30mph limit. Instead of raising the speed limit, it was lowered even further.
I asked Monmouthshire council why the road through through Rogiet won't also be made exempt, the claimed that it can't be. They also claimed that "changing motorists behaviour/mindsets will take some time". 

This decision appears to overlook the historical context of why the previous 20 mph limit was abandoned in 1930. Furthermore, it comes despite the high levels of non-compliance with the existing 30 mph limit, which was well established on that road.
The notion that people just need 'time to get used to it' fails to recognize that most drivers are already focused on avoiding accidents and ensuring the safety of others. It presupposes that the speed limit functions because people become accustomed to it, rather than existing to identify reckless drivers. There's also an assumption that individuals who drive too fast for the conditions do so because the limit allows them or due to a lack of signage instructing them otherwise.
Moreover, there's an underlying assumption that setting rules with an air of contempt will be reciprocated with respect. The concern here is that a significant number of vocal advocates for this change seem to assume that the majority of drivers don't accurately assess their speed and further assume that these drivers will improve their behaviour solely due to a change in signage

I initially assumed that the implementation would include the use of repeaters. However, under the new rules, all repeaters on current 20 mph roads are set to be removed. The updated regulations state that the limit will be 20 mph wherever there are street-lights, while 30 mph limits will require repeaters.
In contrast, in the rest of the UK, 30 mph repeaters on roads with street-lights are forbidden.
This disparity between Wales and the rest of the UK creates a conflict in the systems, likely to lead to confusion.

From my observations in other parts of Wales, it appears that many high standard main roads, which one would assume should be exempt, are being included in the 20 mph limits. For instance, in Newport, roads like Cardiff Road, with its substantial width and clear design for at least a 30mph limit and Chepstow Road, which had a 40 mph limit until recently, are not being made exceptions.
In Cardiff, the situation is even more remarkable, as they have included some roads that would be allowed to be made exceptions.

And here lies the predicament: the new guidelines prohibit local authorities from taking into account average speeds, levels of compliance, or engineering recommendations when establishing speed limits. It appears as if the assumption is that there was never a valid reason to consider these factors in the past.

All too often, both sides of the speed limit debate miss the mark. I've heard opponents of these changes argue about the increase in travel time, but I find this irrelevant when over 90% non-compliance is likely, and free-flowing traffic speeds only decrease by 1-2 mph.

It's crucial to distinguish between speed limits and actual traffic speeds, and that's the real challenge for most people. Traffic speeds are primarily influenced by road design and conditions at the time, not by speed limits. This phenomenon stems from how our brains process information and respond to the driving environment, rather than a deliberate disregard for the law. Therefore, it's essential to consider traffic speeds when setting speed limits.

However, this conclusion, rooted in real-world human behaviour and traffic dynamics, often faces opposition from proponents of lower speed limits, especially in areas advocating for 20 mph limits. It seems that concerns are dismissed regardless of the level of non-compliance or if the average speed exceeds the limit. This dismissal can hinder addressing the root issue, which is the need for improved road design to ensure safer and more efficient traffic flow.

I tried to send a Cardiff councillor Dan De'Ath a link to a video from a road safety organisation on the importance of taking account of real world human behaviour in the setting of speed limits and this is what happened. I he just bocked me, this is argument from ignorance as it's finest.

What's perplexing about this approach is its lack of evidence. There seems to be an assumption that speed limits are something you can set and expect everyone to follow, rather than viewing them as a legal tool to identify reckless drivers. However, there's a significant contingent of people who expect or want them to function in that manner. The problem is, even if you try, they don't. I'm not saying you have to like it.

If non-compliance rates are reaching up to 99%, with over 90% being the new normal, it raises a critical question: what am I missing here? This approach not only poses dangers by normalizing speeding and making it socially acceptable but is also insidious because its proponents claim to want the opposite.

Speed limits are designed to assume ideal conditions; hence, we have other laws such as reckless, dangerous, and careless driving. No one can cause harm at an unsafe speed and use 'I wasn't speeding' as a defence.

Driving significantly slower than the majority of other traffic, causing a tailback, is normally a violation of rule 169 of the highway code and is considered a major fault on a driving test. There's a good reason for this.
Individuals attempting to strictly adhere to the speed limit inadvertently increase their risk of accidents by driving much slower than the flow of traffic. This slower pace can lead to traffic bunching up behind them, introducing distractions and potential hazards on the road.

I encounter a challenge when attempting to delve into great detail to offer a comprehensive explanation of the myriad factors contributing to speed limit non-compliance, particularly when these limits don't align with road engineering. For some individuals, no matter how effectively I articulate these reasons and highlight the exacerbating factors, real-world human behaviour is often met with hasty generalization, appeal to motive, appeal to the law, ad hominem, appeal to the stone, and Bulverism.
This makes engaging in a nuanced discussion about the complexities of traffic behaviour and road safety very challenging.

There is a common belief that if you set the limit lower, people who drive too fast only exceed the posted limit by 5 or 10 mph. I have seen three different councillors make this claim, I normally retort by asking them if that's how they drive or if they could drive safely if their speedo were to brake.
According to DfT Circular Roads 1/80 "It is a common but mistaken belief that drivers allow themselves a set margin over the prevailing speed limit, and that if a limit is raised by 10 mph, they will travel 10 mph faster. In fact, an increase in an unrealistic speed limit rarely brings an increase in traffic speeds.
It is much more likely that there will be no change, or even a fall. It seems that drivers relieved of the frustrations of too low a limit rarely abuse the higher one."
I've seen plenty of more recent data that backs up this and I wrote about it previous.
So, not only is it untrue, the reality is the opposite when the limit is set artificially low.

Far from limits targeting unsafe drivers more effectively, this approach prohibits the behaviour of some of the safest drivers on the road and forces the police to focus on them.
This comes at the expense of addressing the behaviour of motorists who are not only the least likely to slow down when limits are lowered but also the most likely to cause harm.
Moreover, these laws may exist to shift responsibility, as when almost all motorists exceed the speed limit, every accident becomes the driver's fault, and the government is no longer held responsible for poor road design or maintenance.
This is before I even address issues such as vulnerable road users such as pedestrians and cyclists having false expectations of actual traffic speeds, satellite navigation systems no longer considering main roads as faster and people overtaking.

If you complain about this, the assumption seems to be you must be some kind of uncaring petrol head. Nope, I understand how speed limits are meant to function, I genuinely think it's dangerous.
If you really want to make the roads safer you need to spend money on changing the design of the road, and for arterial roads you need to provide safe places for people to cross and be sure pedestrians know realistically what speed traffic is likely to be going.