We critique Hampshire County Council's 20mph Review

On 5th June Hampshire County Council published a report reviewing its trial of 20mph limits. Whilst we believe that the trials were poorly implemented they still gathered support from communities and in our eyes were moderately successful. We were disappointed that rather than analysing what it could do better in providing future 20mph limits to communities the report chose to ignore its own failures in implementating best practice and instead recommend against future similar schemes.

Here we critique the report in detail and call on Hampshire County Council to review its policy on 20mph limits.

The following critique may be downloaded here

20’s Plenty for Us calls for Hampshire County Council to withdraw its report on the 20mph Pilot Programme and to press ahead with rolling out 20mph in residential streets across the county.


20’s Plenty for Us has conducted a detailed review of the report dated 5th June 2018 into Hampshire County Council’s 20mphPilot Programme[1].  We draw different conclusions from the Director of Economy, Transport and Environment.  Rather than rejecting 20mph, HCC should recognise the benefits that the pilot schemes have already brought to local communities in Hampshire and extend 20mph to all residential streets, including narrow residential rural lanes and town and village centres in the county.

An example of how Hampshire signs its 20mph limits. This one in Whitchurch

Summary conclusions

The report itself has a number of failings:

  • draws the wrong conclusions from the data provided;
  • local community support for 20mph schemes ignored;
  • latest research on 20mph not considered;
  • inaccurate references to Department for Transport’s guidelines on setting local speed limits; and
  • success criteria of the schemes not set out clearly, making it hard to judge “success”

Most Local Authorities that have introduced 20mph have seen major benefits in terms of community support and engagement, lower speeds, casualties reduced by around 20%[2] and increased levels of cycling and walking.  It is clear that the pilot schemes are supported by the community and have brought benefits.  However, if HCC has not seen the same level of benefits of 20mph as other Local Authorities, then it needs to examine the pilot schemes in detail and learn lessons about how to achieve greater benefits. These could include:

  • ensure that the schemes are sufficiently wide and in appropriate places;
  • more education to drivers and enforcement, including promoting Community Speedwatch;
  • assessing whether more signs or road engineering measures are required; and
  • whether there is sufficient budget.

None of the matters are explored in the report.


  • Withdraw the recommendations to cancel further 20mph schemes;
  • Council officers to investigate lessons learned from the pilot schemes;
  • Council officers to report back with recommendations about how 20mph schemes can be implemented more successfully; and
  • Use the findings to roll out 20mph across all residential streets and in town and village centres.


Detailed comments on the report

Our comments fall into four categories

A. Credibility of report’s provenance, considering HCC poor performance in reducing road danger

B. Report inaccuracies

C. Scheme design and implementation

D. Invalid casualty statistics presented

A.     Report credibility

Given Hampshire CC's record on road safety, it is hard to give credence to the report.  HCC is consistently in the top 3 worst performing Local Authorities in the country for people killed and seriously injured (KSI) on its roads – 757 in 2016. 

In 2016, 757 people were killed and seriously injured (KSI) on Hampshire roads[3], up from 618 in 2005[4] and back to the peak number of KSIs recorded in 2011. The increase of 23% compares with the national picture, where KSIs are DOWN by 20% over the same period.

In comparison, Portsmouth reported a fall of 22% in KSIs following the introduction of wide area 20mph.  Since 2005, KSIs in Portsmouth have risen by just 5%[5] and are 22% below the 2011 peak.

The picture for vulnerable road users (pedestrians, cyclists, motor cyclists), in Hampshire is particularly concerning – 57% higher since 2005.

It is urban roads which would benefit most from 20mph that are the most dangerous - 44% of all KSIs were on 30mph roads in Hampshire in 2016, including 57% of vulnerable road users KSIs.  A further 12% of KSIs occurred on 40mph roads.

B.     Report inaccuracies

There are many inaccuracies in the report, under four headings:

  1. Misleading references to the DfT’s guidance on setting local speed limits
  2. Wrong conclusions from the data included in the report – 20mph is demonstrated to be an appropriate speed limit for nine out of 14 areas. Four out of the other five areas have seen benefits from 20mph of lower speeds or a reduced range of speeds recorded. We note that one area, Alton, has been excluded altogether
  3. Benefits of relatively small reductions in speeds ignored
  4. Latest air quality research omitted



1.      DfT guidance – misleading references

References to the DfT’s guidance on setting local speed limits from January 2013 [6] are incomplete and, therefore, misleading.

a. HCC erroneously conflates the need to set an appropriate speed limit for a particular road with the measures needed to gain compliance. The DfT guidance is quite clear in separating the two points – guidance on the principles for setting the speed limit for a road is contained in section 2, with the statutory framework outlined in section 4.  Further details for both are provided in sections 6 (urban roads) and 7 (rural roads).

b. In HCC’s recommendations, the report proposes…

“That any future speed limit schemes will be prioritised in accordance with the Traffic Management policy approved in 2016, and thereby limited to locations where injury accidents attributed to speed are identified, with proposals assessed in accordance with current policy and Department for Transport guidance on setting speed limits.”

While we haven’t see the Traffic Management Policy from 2016, we note that the DfT criteria not limited to “locations where injury accidents (sic) attributed to speed are identified”.  In its introduction, the DfT guidance states:

Traffic authorities are asked to keep their speed limits under review with changing circumstances, and to consider the introduction of more 20 mph limits and zones, over time, in urban areas and built-up village streets that are primarily residential, to ensure greater safety for pedestrians and cyclists[7], using the criteria in Section 6.

Not only HCC has failed to ensure greater safety for pedestrians and cyclists as shown earlier, but by rejecting 20mph, the report fails to suggest future improvements.

c. The report omits the numerous benefits of 20mph highlighted in the DfT guidance. Although not mandatory, the clear implication is that DfT expects Local Authorities to introduce 20mph wherever possible. E.g. In the introduction to section 6, which gives the criteria for setting local speed limits, the DfT guidance says:

Traffic authorities can, over time, introduce 20mph speed limits or zones on:

Major streets where there are – or could be - significant numbers of journeys on foot, and/or where pedal cycle movements are an important consideration, and this outweighs the disadvantage of longer journey times for motorised traffic.

This is in addition to

Residential streets in cities, towns and villages, particularly where the streets are being used by people on foot and on bicycles, there is community support and the characteristics of the street are suitable.

As well as residential streets, the DfT expects major streets to be 20mph, unless the disadvantage of longer journey times for motorised traffic can be shown to outweigh the needs of pedestrians and cyclists.  HCC’s decision to cancel all future schemes directly contradicts this expectation.

d. Critically, the table showing how the DfT expects Local Authorities to set the appropriate speed limit for a particular road is missing.

Speed limits in urban areas – summary (mph)

Where limit should apply

20 (including 20 mph zone)

In streets that are primarily residential and in other town or city streets where pedestrian and cyclist movements are high, such as around schools, shops, markets, playgrounds and other areas, where motor vehicle movement is not the primary function.


In other built-up areas (where motor vehicle movement is deemed more important), with development on both sides of the road.


e. Although there has been a benefit at some locations from a drop in the range of speeds, this is not highlighted in the report summary, ignoring the DfT guidance, which says:

The underlying aim should be to achieve a 'safe' distribution of speeds.

f. In deciding on the speed limit for a particular road, HCC ignores many of the DfT factors:

  • history of collisions;
  • road geometry and engineering;
  • road function;
  • Composition of road users (including existing and potential[8] levels of vulnerable road users);
  • existing traffic speeds; and
  • road environment.

While these factors need to be considered for all road types, they may be weighted differently in urban or rural areas. The impact on community and environmental outcomes should also be considered[9].

In basing its recommendation entirely on the history of collisions and traffic speeds, HCC ignores the overwhelming support of residents and, in particular the needs of vulnerable road users.



2.      Wrong conclusions in report from the speed data shown.

a. Table 1 in the report, which shows the number of vehicles travelling at less than 20mph before and after the speed limits were introduced is a completely irrelevant measure. The question regarding speeds is not only whether there has been a reduction in average speeds, but also the range of speeds and, whether speeds over, say 30mph, have come down. The report contains insufficient details to draw such conclusions and we have submitted a Freedom of Information request for these.

b. Average speeds on their own are unreliable. We constructed the following example (Site 1) to show where the range of speeds had reduced by 10 mph and the top speed reduced by 5mph, but the average has gone up. This example shows success; in the HCC report, it would be shown as a failure


c. Even if we accept HCC’s own methodology and criteria, we draw different conclusions from the data submitted:

  • Using 24 mph as the benchmark misunderstands the DfT‘s position. However, if we accept HCC’s success criteria for 20mph as roads being below 24mph, then the report shows that 9 of the 14 locations are suitable for 20mph.  If the sites are representative of other places in Hampshire, this means that there will be many suitable sites for 20mph in the county;
  • Further benefits exist in 4 of the remaining 5, either through speed reductions or a lower speed range;
  • In 12 of the 14 locations, speeds have fallen or stayed the same;
  • In 10 of the 14 locations, the range has fallen or stayed the same
  • Further interventions may be necessary to reduce speeds or spreads further

d. Detailed analysis of speed data included in report

  • Using HCC’s 24mph criteria, 9 out of 14 locations have the right speed limit (coloured green in the table below);
  • Fleet has benefited from a speed reduction of 2.5mph and a drop in the range of speeds by 1.5mph, although still above 24mph;
  • Of the other 4 locations, average speeds are in the range of 25mph to 27mph but the range of speeds has reduced in 3 locations (coloured orange);
  • Further investigation would show the measures needed to bring average speeds down and to check the reasons for increases in spread at various locations.

We note that the report does not state the number of vehicles exceeding 30mph.

Table of locations, average speeds, range of speeds before and after implementing 20mph limits






1)    Wallington:

17mph both


No material change to avg or range. 

Right speed limit

2)    Eastleigh:

20mph to 18mph


Speed down 2mph; similar range. 

Right speed limit

3)    Stanmore

24mph both

5mph to 4 mph

No material change; range down 1pmh

Right speed limit

4)    Medstead

25.3mph to 23.8mph

11mph to ; 14mph

Speed down 1.5mph; range up 3mph

Right speed limit; investigate increased range

5)    Hythe(*)

23mph to 22mph

6mph to 5 mph

Speed down 1mph; range down 1mph

Right speed limit

6)    Floral Way

22mph both

8mph to 5mph

Same speed, range drop 3 mph

Right speed limit

7)    Whitchurch

27mph both

6.5mph to 5.5mph

Same speed, range down 1mph

Measures needed to reduce speed further

8)    Farnborough

22mph to 21mph

2mph to 4mph

Speed down 1mph; range up 2mph

Right speed limit; investigate why increased range

9)    Fleet

27.8mph to 25.2mph to 26mph

6.4mph to  4.7mph to 5.1mph

Speed down 3mph (2.5mph); range down 1.5mph

Measures needed to reduce speed further

10) Chilbolton

27mph both

3.4mph to 1.8mph

Same speed; range down 1.6mph

Measures needed to reduce speed further

11) Dummer

23.5mph to 25mph

4mph to 0.5mph

Speed up 1.5mph range down 3.5mph

Right speed limit;

12) Micheldever

25mph both

4mph to 6mph

Same speed; range up 2mph

Right speed limit; investigate why increased range

13) Winnal

18mph both

3mph to 6mph

Same speed; range up 3mph

Right speed limit; investigate increased range

14) Highcliffe

21mph both

9mph both

Same speed and range

Right speed limit; investigate large range


(*) report wrongly states that before and average speed are >24mph.

3.      Benefits of relatively small speed reductions.

At section 9, the report states that “signed-only 20mph schemes generally achieve relatively small speed reductions of 1–2mph.”  Even if this were the case, the research evidence is that a 1mph reduction in speeds brings a 6% reduction in casualties, in itself a saving worth having.  It also ignores the recent findings from (e.g.) Bristol which shows an average of 2.7mph and, more importantly, greater reductions on higher speed roads.

4.      Air quality

The report states at section 10 that the research on the impact on Air Quality is mixed, but this ignores the latest evidence from NICE and from Wales, which show the benefits of 20mph:

a. NICE, which recommended 20mph as a way to improve air quality. https://ecf.com/news-and-events/news/nice-recommends-speed-limits-20mph-improve-air-quality

b. An analysis on roads in Wales by Jones, S. J. And Brunt, H. (2017) ‘Twenty miles per hour speed limits: a sustainable solution to public health problems in Wales’, Epidimol Community Health http://jech.bmj.com/content/71/7/699 concluded “evidence review suggests benefits in terms of road traffic casualties, air quality, active travel, noise pollution, greater social inclusion, greater community cohesion and local business viability.

C.     Scheme deficiencies

1. Since the success criteria of the tests are unclear, the assessments are invalid E.g. #2.1 states:

The schemes in question were selected in consultation with members of the County Council and the community after initial testing against a set of agreed criteria,

…but the criteria used are not specified.  The report does state:

The decision to start the pilot schemes was taken before the current Traffic Management Policy of 2016 came into being, which requires all future Traffic Management schemes to be led by safety and casualty reduction interventions,

…which implies that safety and casualty reductions were not the criteria used. Yet, Adrian Gray, the Head of Highways at HCC is reported in the Daily Echo of 12th June 2018 as saying

“The decision to implement this pilot was part of our traffic management scheme, in the pursuit of casualty reduction. However, we have found that the impact on traffic speeds were largely minimal”

As well as misleading – small decreases in average speeds can bring significant benefits – the statement contradicts the report in saying that casualty reduction was an objective.  If this were an aim, then alternative sites with more casualties would have been more appropriate.

2. Enforcement:

It is the Police’s job is to enforce all speed limits and we doubt that Hampshire Constabulary would single out 20mph for “lack of enforcement”.  If so, then they need to refer to ACPO (now NPCC) guidance from October March 2013, which stated “We can clearly state that it is incorrect to say that police officers are not enforcing 20mph speed limits.”[10]

However, the Police do not have the resources to enforce all speed limits at all times. It is, therefore, the role of the Local Authority to design schemes in a way that they are likely to achieve the required objective, including implementing Vehicle Activated Speed Limit Reminders and promoting, e.g. Community Speedwatch

3. Schemes omitted from the report. We understand that there is strong support for extending the town centre 20mph limit in Alton to other residential roads, yet there is no mention of Alton in the report.  We understand the scheme is successful, despite concerns that the traffic calming measures were poorly designed.  Local residents were led to believe that the town centre was part of 'a pilot' and that other 20mph limits would be postponed until the trial was finished.

If the trial is now finished, then the extensions should be implemented.  Further, if Alton has been excluded, the questions is whether there are other schemes which have also been omitted.

D.    Casualty statistics

We await the outcome of a Freedom of Information request submitted to HCC to establish the robustness of the quoted conclusions. However, it is clear from the report that 90 casualties over 5 years – 18 per annum - across several schemes are too few to be statistically significant. In addition, some schemes have only been live for a few months and more data would be needed to confirm the impact of 20mph on casualties.  Larger case studies in other areas – Bristol, Edinburgh, Portsmouth – show clear benefits, with reductions averaging 20%.

Critique compiled by Adrian Berendt, 20’s Plenty campaigner for South England

Open PDF


[1] “Review of Residential 20mph Pilot Programme”

[2] E.g. Bristol (casualties down 14%); Calderdale (22%); Edinburgh (24%); Newcastle (25%); Portsmouth (20%)

[3] http://www.travelindependent.org.uk/area_133.html

[4] Earliest available data to the author

[5] http://www.travelindependent.org.uk/area_124.html

[6] https://assets.publishing.service.gov.uk/government/uploads/.../circular-01-2013.pdf

[7] Author’s emphasis

[8] Author’s emphasis

[9] Author’s emphasis

[10] https://www.richardsilver.co.uk/news/police-announce-new-20mph-zone-enforcement-guidelines/

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