Speed Enforcement: Your Questions Answered

Speeding is one of the most common contributing factors in fatal and serious road collisions. Through targeted enforcement and education, we aim to reduce harm, prevent tragedy, and protect communities.

This article answers the questions we’re most frequently asked about how and why we carry out speed enforcement.

Why do you carry out mobile speed enforcement?

A: Excess speed is a lead contributing factor in fatal and serious collisions, with higher speeds directly causing more severe injuries. Mobile enforcement helps prevent harm by encouraging safer speeds and deterring dangerous driving.

Shouldn’t the police be focusing on more serious crime?

A: Road collisions are one of the leading causes of sudden death and serious injury in the UK — more so than many other types of crime. Every 17 minutes*, someone is killed or seriously injured on our roads – and speed is a factor in over half of fatal collisions.** Mobile speed enforcement helps to reduce this harm and protect the public.

*Source: Brake.org.uk (10-year average, 2014–2023)
**DfT RAS0704 (10-year average to 2023)

Are there rules you must follow when enforcing speed limits?

A: Yes. Our officers follow national operational guidance from the National Police Chiefs’ Council (NPCC), ensuring that all enforcement is fair, consistent and legally sound.

Don’t speed enforcement vehicles have to be visible, and with warning signs that enforcement is being carried out?

A: No. There’s no legal requirement for enforcement vehicles to be visible or for warning signs to be used. While some national guidance encourages visibility, we can lawfully use unmarked vehicles where needed – particularly where previous visible enforcement hasn’t reduced speeding.

Do enforcement officers only deal with speeding?

A: No. We use technology to detect other high-risk offences including mobile phone use, not wearing a seatbelt, illegal number plates, and ignoring traffic signs – all linked to serious injury and fatal collisions.

Do you enforce 20mph limits?

A: Yes. We enforce both 20mph limits and zones, especially near schools and in residential areas where pedestrian risk is higher.

Is speed enforcement just about making money?

A: No. The aim is to change driver behaviour and prevent collisions. Any money recovered from speed awareness courses is reinvested into road safety education and enforcement – not into general policing budgets.

What kind of equipment do you use?

A: We use Home Office-approved handheld and vehicle-mounted speed detection devices. These can measure speeds at distances of up to 750 metres.

How are locations for speed enforcement chosen?

A: Locations are chosen using evidence from collisions, community concerns, and data from previous enforcement and Community Speed Watch. We focus on places with proven speeding issues and high collision risk.

Can you carry out speed enforcement at night or in the dark? 

A: Yes. Our enforcement equipment is fitted with infrared technology, allowing us to detect speeding and capture registration plates even in total darkness. 

What can I do if I’m concerned about speeding in my area?

A: You can join our Community Speed Watch scheme to help monitor and raise awareness of speeding where you live. Learn more here → Community SpeedWatch | Avon and Somerset Police

Do you operate as part of a partnership with local authorities?

No. The Avon and Somerset Police Road Safety Enforcement Unit is responsible for enforcement. However, we work closely with local councils and other partners on road safety strategies.

Do you have to be a regular police officer to carry out speed enforcement?

No. Our enforcement officers are trained operational Police Staff. The law allows civilian staff to operate speed detection equipment and issue Notices of Intended Prosecution (NIPs).

What happens if someone deliberately blocks or obstructs a speed camera?

Deliberate obstruction of an officer or camera can be a criminal offence. Under the Police Reform Act 2002, obstructing a designated person in the execution of their duty can result in prosecution and up to 51 weeks’ imprisonment.

Are there rules about where enforcement vehicles can park?

Yes. Police vehicles engaged in operational duties are legally exempt from certain parking restrictions. Locations are always risk assessed to ensure safety.

Do you need a history of collisions on a road to start enforcing?

No. We also take proactive steps based on community feedback and speed data. Enforcement can happen where persistent speeding is detected – even without a history of serious crashes.

Can you enforce speeds from anywhere on the road?

Each enforcement location is pre-surveyed and given a unique site code. Officers can operate within a 1km stretch either side of that code, depending on risk and visibility.

Is there an allowance before speeding penalties apply?

We follow national operational guidance that sets enforcement thresholds starting at 10% + 2mph of the posted speed limit. This is not an official allowance or ‘safe margin’ – it’s a technical threshold used to ensure consistency and account for equipment calibration. However, the law is clear: exceeding the speed limit by any amount is still an offence.

Can you enforce against motorcycles that don’t have front number plates?

A: Yes. Motorcycles are not exempt from speed enforcement. Our vehicles are equipped with additional cameras that record the rear of passing vehicles, allowing us to capture the number plate even when there is no front plate – as is the case with most motorcycles.

What if there are no speed limit signs on the road?

A: If a road has street lighting (lamp posts no more than 200 yards apart) and no repeater signs, it is legally a 30mph limit. In these cases, the presence of streetlights and absence of signs means the default limit applies.

If the road is a 30mph limit without street lighting, repeater signs must be in place.

On roads with other speed limits – such as 20, 40 or 50mph – you’ll see repeater signs at regular intervals, regardless of whether there’s street lighting.

How soon will I receive paperwork after being caught speeding?

A Notice of Intended Prosecution must be sent to the registered keeper within 14 days of the alleged offence. If the vehicle is leased or hired, this time frame applies to the leasing company, not the driver.

🚧 Still have questions?

We’ll continue to update this page with answers to your most common and technical questions about speed enforcement.

To report concerns or get involved in local speed awareness, visit our Community Speed Watch page or get in touch with your local policing team.