Eco-Driving: how driving style affects accident rates, wear on vehicles and fuel consumption

A sharp start from the lights on Heydar Aliyev Avenue, braking flat to the floor in front of a camera on the M-2, an overtake on the hairpins of the road to Quba. Taken one at a time these are trifles. Over a month a single driver racks up hundreds of them, and each one leaves its mark in fuel consumption, in brake pad wear and in the risk of a crash.

Eco-Driving is often sold as a fuel-saving tool. That is half true: the same report shows which of your drivers regularly end up in dangerous situations. Let us look at how the score is built, where the figures for its effect come from, and how to introduce the system so that drivers do not take it for surveillance.

What Eco-Driving measures

The name comes from the European programmes for reducing CO₂ emissions. In monitoring systems it is taken to mean an automatic assessment of driving style from the data of a GPS tracker.

The tracker records four types of event:

• Harsh acceleration — the pedal to the floor at the lights
• Harsh braking — an emergency stop instead of easing off smoothly
• Speeding — going past a set threshold
• Harsh cornering — lateral loading during manoeuvres

From the total of the events, weighted by severity and mileage, the driver gets a score — in the Eco-Driving module of the Wialon platform this is a scale on which fewer penalty points means a calmer style. The history builds up across every trip, and after a month it is clear whose violations are accidental and for whom this is simply the way they drive.

Speed and risk: where the figures come from

The link between speed and accident rates is well studied. According to the World Health Organization (its speed management materials, based on the Nilsson model), a 1% rise in average speed increases the risk of a fatal crash by roughly 4%, and of a crash with serious injuries by roughly 3%. This is general road traffic statistics, not the result of rolling out monitoring.

The physics of braking is simpler. The stopping distance is made up of the distance covered during the driver's reaction time and the braking distance itself. On dry tarmac at 50 km/h that comes to roughly 25–30 metres; at 70 km/h it is already around 45–55 metres. At a pedestrian crossing that difference decides everything.

Money: how to work out the effect for your own fleet

Fuel. According to the US Department of Energy (the fueleconomy.gov site), aggressive driving reduces the fuel economy of a passenger car by roughly 15–30% on the motorway and by 10–40% in the urban cycle. For lorries and buses the figures are different and depend heavily on the route, so they cannot be carried across directly.

An indicative example for a lorry on the Baku — Ganja run (about 360 km): at a norm of 30 litres per 100 km the trip swallows about 108 litres. If harsh driving adds 10%, that is about 11 litres a trip. Multiply by the number of trips in a month and you get an order of magnitude that you can then check against your own data over the first two or three months.

Maintenance. Harsh braking accelerates the wear of pads and discs; harsh cornering loads the suspension and the tyres. There are no reliable general percentages here. It is more honest to compare the pad replacement intervals of drivers with high and low scores within your own fleet after six months.

How it works technically

A tracker that supports Eco-Driving — one from the Teltonika FMB range, for instance — uses an accelerometer to register loading along each axis. Every event is written down with its time, its coordinates and the speed. The dispatcher sees not just a track but an annotated route: where the harsh braking happened and at what speed.

How to set the thresholds

The factory thresholds are only a starting point. They have to be fitted to the vehicles, otherwise the report will be either empty or red for everyone.

• Different profiles for different vehicles. A loaded tipper and a saloon car physically accelerate in different ways. One threshold across the whole fleet produces false positives on the light vehicles and misses on the heavy ones.
• Calibration for the mounting position. The accelerometer has to know how the tracker is fixed in the vehicle — that is part of the fitting and configuration. Without calibration a corner can be read as braking.
• Speed thresholds by zone. In Wialon you can set different limits for the city, for motorways and for geofences — the grounds of a base or an oilfield, say.
• A trial period. For the first two or three weeks the report is collected without any conclusions being drawn about drivers: you look at how the events are distributed and adjust the thresholds until false positives become rare.

How to introduce the system to drivers

1. Announce it in advance. Explain exactly what is measured and why. In the event of a crash the tracker record can show that the driver was within the limits — an argument in his favour.
2. Show the driver his score. He should see his own total after a shift and understand which event cost him points.
3. Review rather than fine straight away. Harsh braking may be the right reaction to a pedestrian. A disputed event is reviewed against the track and, where it exists, against the camera footage.
4. Combine reward with consequence. A monthly ranking with a bonus for the best drivers is usually accepted better than penalties alone. But systematic gross violations (going 40 km/h or more over the limit, dangerous overtaking) need clear consequences, written into an internal procedure.
5. Revisit it every quarter. The thresholds, the weightings of events and the bonus rules change along with the fleet and the routes.

Eco-Driving on long-distance routes

On runs along the M-2 to Qazakh, along the M-1 towards the Russian border or along the M-3 to Astara, the driver spends many hours at the wheel, often at night. Here a neighbouring function is useful — monitoring of driving and rest time (for international runs this also means working with tachographs): the system counts continuous time at the wheel and sends the dispatcher a notification if the driver goes past the set limit without a break.

The limits of the method

• The score does not see the traffic situation: harsh braking because another car cut in looks exactly like braking through inattention.
• Poor mounting of the tracker, or no calibration at all, produces false events.
• Speeding is measured against a set threshold rather than against the actual sign on that stretch, unless zones are configured in Wialon.
• Fuel savings appear only when someone works with the report — as is also the case with fuel control. The report by itself does not reduce consumption.

A launch checklist

• the trackers are calibrated, and each group of vehicles has its own threshold profile;
• the drivers know what is measured and how the score is worked out;
• someone is appointed to look at the report once a week and review disputed events;
• the rules on rewards and consequences are written into an internal document;
• after 2–3 months, consumption and the number of events have been compared with the period before launch.

There is more about the function on the driving style monitoring page. If the fleet includes rental vehicles or taxis, the breakdown of the hidden losses of a fleet is a useful companion, and on choosing the tracker itself there is GNSS versus GPS.