Speed Limits and Review Process

​Posted speed limits on the county network account for one of the greatest causes for public complaint. When requests are received, Northamptonshire Highways and Northamptonshire Police undertake a formal review which involves a panel of relevant officers, chaired by the Road Safety Manager, and includes the Highways Community Liaison Officer for the area in question; the Principal Highways Engineering Officer; safety engineers; road safety practitioners and the Safer Roads Team Leader for Northamptonshire Police. He has delegated authority from the Chief Constable in speed limit consultations. The Panel is therefore able to provide a consensus decision from both organisations.

In general, we are mindful that determining an appropriate speed limit is not an exact science and can often divide opinion, particularly when the road characteristics and environment changes rapidly over relatively short distances. During our monthly meetings, the Panel takes an evidence led approach and evaluates all the available speed, volume and collision data, supporting information, environmental impacts and road characteristics. In addition, members of the panel will have visited the identified locations prior to the meeting in order to experience, first-hand, the current restriction in place so as to form an opinion regarding any proposed amendment. The Panel also takes account of range of other factors, which include, but are not limited to:

  • criteria and guidance ‘Setting Local Speed Limits’ developed by the Department for Transport (DfT)
  • Association of Chief Police Officers (ACPO) Speed Enforcement Policy Guidelines NOTE: ACPO has now been superseded by the National Police Chiefs Council
  • it should be obvious to a careful and competent motorist why a speed limit is in place and should reflect the function of the road, geometry and environment
  • a speed limit should seek to reinforce people’s assessment of what is a safe speed to travel to encourage self-compliance
  • the potential for reducing collisions and casualties in areas with a known history
  • any use of traffic calming features must be proportional, aesthetically acceptable and supported by the emergency services
  • there should be no expectation of the police to provide additional enforcement beyond their routine activity

It should be noted that this speed assessment process does not imply that speed limits will automatically be reduced. Indeed, in some cases, the assessment may suggest that the existing speed limit may already be inappropriately set too low, and an increased limit could be considered.

For further advice regarding a speed limit review please contact your Highways Community Liaison Officer: 


20mph Speed Limits

In order to have a meaningful impact Northamptonshire County Council is supportive of 20mph restrictions but generally in areas where vulnerable road users tend to be at risk. This means that the vast majority of new 20mph restrictions in the county have been in relatively localised areas outside primary schools and the traffic calming element is normally in the form of vehicle activated signs.

20mph limits covering a wider area tend to be contentious, and also more expensive as they generally require physical traffic calming measures in the form of speed humps, raised platforms or chicanes in order to gain compliance.  These can often have a detrimental aesthetic and visual impact on a village environment.  A signed only scheme will have little effect and the police are keen to emphasise that there should be no expectation on them to provide speed deterrent activity in schemes that should be self-enforcing.

With limited funding available it is also essential that we direct our resources to where they are most needed.  We would therefore have some expectation that a speed reduction measure has potential to deliver a collision and casualty reduction benefit.

At present we know that the evidence contained in studies into schemes around the UK is inconclusive in terms of the benefits delivered. However, the Department for Transport has commissioned research into the effectiveness of 20mph speed limits in order to support and inform future policy development.

The project will set out to evaluate the effectiveness of 20mph speed limits in terms of a range of outcomes including speed, collisions, injury severity, mode shift, quality of life, community, economic public health benefits and air quality. It will also examine drivers’, riders’ and residents’ perceptions of 20mph speed limits and assess the relative cost and benefits to specific vulnerable road user groups including children, cyclists and the elderly. The study is a three-year project with a final report anticipated late 2018 or early 2019.

We are therefore naturally cautious in terms of implementing 20mph speed restrictions and are hopeful that this research will deliver a clear insight, and evidence led approach into the most effective intervention.