The Importance of Tracking your Speed

Driving with excessive speed is one of the main factors in fatal road accidents according to the government’s THINK! road safety campaign, a fact they drove home in their hard-hitting TV ad released in 2009. They state on their website that “in 2013, 3,064 people were killed or seriously injured in crashes where speed was a factor”.

Most importantly, driving at a safe speed can help save lives; but failure to stay within the speed limits can also affect your drivers’ ability to work. The minimum penalty for speeding is a £100 fine combined with 3 penalty points added to the licence of the driver, although the penalty points can be as high as 6 for more serious breaches. These endorsements remain on the driver’s licence for four years, and if a driver builds up 12 or more penalty points within a period of 3 years then they will be disqualified from driving; and for new drivers that are within 2 years of passing their test, 6 or more penalty points will lead to their driving licence being revoked. More details of the endorsement system can be found here.

If a person’s livelihood depends upon driving; it also depends on them staying on the right side of the law, which is where vehicle tracking devices can be of help.

How Accurate are Dashboard Speedometers?

Car speedometers are rarely accurate and can give different readings dependent upon a number of factors. These types of speedometers calculate speed by measuring the number of wheel revolutions over a fixed time, assuming a certain wheel circumference. If the assumed wheel circumference is wrong, then the speedometer reading will also be wrong by the same factor. This can happen for a number of reasons – changing the tyres to a new brand or model, tyre wear over time, tyre pressure and the weight of the vehicle and its load.

In addition to this, car manufacturers tend to calibrate their speedometers to overstate the speed. The UK law with regard to speedometers as laid out in the The Motor Vehicles (Approval) Regulations 2001, schedule 3, item 19 states that “…the true speed shall not exceed the indicated speed” and also that “…the difference between the indicated speed and the true speed shall not exceed V*1.1 + 6.25 mph, where V = the true speed of the vehicle in mph”.

In other words, a speedometer must never read less than the actual speed, and must never read more than 110% of the actual speed + 6.25mph. This means that for a vehicle travelling at 30mph, its speedometer could legally read up to 39.58mph but never less than 30mph. Looking at it an other way, if a speedometer is reading 30mph, the vehicle’s true speed may be anywhere between 21.59mph and 30mph. It’s with these limits in mind that manufacturers calibrate their speedometers – and that’s the reason why the speedometer often suggests a speed that is a few mph faster than that indicated by your satnav or GPS device.

Speedometers typically overstate the true speed of the vehicle

How Accurate are GPS Tracking / Satnav Speedometers

The speed indication given by your satnav receiver or vehicle tracking device is calculated by change in position (as determined by satellite fix) over time. It is inherently more accurate, even more so at higher speeds, than a dashboard speedometer. The accuracy of different units vary, but as a rule of thumb, assuming that there are at least 3 satellites visible in the sky, the GPS reading for speed will be accurate to about ±0.1mph.

Using your GPS for speed data will solve the problem of knowing whether or not you are actually within a stated speed limit, which is something that most people are interested in given the number of speed enforcement cameras employed in the UK today.

What it Means for Fleet Managers

Fleet managers have an interest in keeping their drivers on the road and out of the magistrates courts, and they also want to ensure that their fleet is operating in an efficient and timely manner.

This is where the accuracy of GPS vehicle tracking devices, and their reporting abilities come into their own.

Data reporting in vehicle tracking systems allow fleet managers, amongst other things, to view all instances of speeding across the fleet over any given time period. This data could then be filtered by driver to give an overview of driving style and propensity to exceed the limit. This could be helpful in identifying where training (or a quiet word) may be needed to ensure that speeding penalties are avoided and that the fleet is operating as safely as possible.

A further advantage of recording this data is that in the event of a dispute regarding a speeding ticket or an accident, it can be proven that the vehicle was travelling at a safe speed.

What it Means for Fleet Drivers

Drivers who depend upon GPS for their speed readings will be able to work faster, while staying on the right side of the law.

Moreover, some tracking systems feature audible speed alerts – playing a sound in the cab to warn the driver if a statutory speed limit is exceeded, enabling them to keep within the speed limit while not having to keep an eye on the speedometer all the time. Advanced systems will be aware of individual speed limits on all stretches of road across the entire highway network – further helping to ensure that drivers don’t get caught out.

Choosing a Vehicle Speed Tracking System

While each vehicle tracking system for fleets will vary in features, reporting capabilities and cost, speed tracking and reporting is a principal feature that will be found on all modern systems.

In terms of reporting, some systems will know the local speed limit for any stretch of road – cheaper systems just have one speed limit that is programmable; some systems will report all offences to base in real time (some even have the capacity to set an SMS alert), while others will not. Most systems will have some level of customisability.

Mid-range systems may feature audible speed alerts for drivers, and the higher end systems will be more customisable and will feature real-time speed limit information for each stretch of road.

Before getting getting quotes from suppliers, try to determine which features are most important to you; and which you could do without. Be sure to shop around and get quotes from a number of different suppliers.

Simply complete the form below to get multiple quotes from top suppliers tailored to your needs. There’s no obligation and it only takes a minute.


Author - Nigel Vaughan

Nigel has over 10 years experience in digital marketing, and loves tech and all kinds of electronics. A keen cyclist and cycle-tourist, he has cycled through 25 countries worldwide.

Leave a Reply