Fuel Consumption Optimization

Optimizing fuel consumption means working on one of a fleet's largest expenses. Three levers drive it: how vehicles are driven, how many kilometers they cover, and what condition they are in.

Fuel is a variable cost: it follows every kilometer, every start and every minute of idling. That is why a fleet manager can bring it down without renegotiating a single contract. To see its real weight, put it back into each vehicle's total cost of ownership.

First lever: driving

In town, aggressive driving, with sudden acceleration and repeated braking, uses up to 20% more fuel than smooth driving, according to France's environment agency (ADEME, in French). Over-revving the engine can also use up to 20% more, and idling for more than 10 seconds uses more fuel than switching off and restarting (ADEME).

Telematics makes these habits visible, trip by trip: acceleration, braking, speed and idle time. The eco-driving entry covers the right habits, and the driving behavior entry covers what gets measured. An employee's driving data is personal data: in France, monitoring it follows the framework set by the CNIL, summarized in our telematics and GDPR guide.

Second lever: kilometers

A kilometer avoided burns no fuel. Route optimization sequences stops, accounts for traffic and time windows, and removes detours. Good planning also cuts empty runs.

Speed matters too. Driving 10 km/h slower on the highway saves between 1 and 3 liters over a 500 km trip, depending on the engine and the vehicle (ADEME). The trade-off: a Lyon–Paris trip takes 18 minutes longer.

Third lever: vehicle condition

A poorly maintained vehicle uses more fuel. Three points come first:

• Tire pressure. Under-inflation by 0.3 bar increases consumption by 1.2%, and by 2.4% at 0.5 bar. ADEME recommends checking it at least once a month with cold tires, and puts the saving from low-rolling-resistance tires at up to 5% of fuel (ADEME).
• Unneeded equipment. A roof box, roof rack or bike carrier left in place causes 10 to 20% overconsumption (ADEME).
• Engine maintenance. Filters, oil and settings follow the manufacturer's schedule. Preventive maintenance keeps a missed service from showing up as extra liters.

Air conditioning weighs in as well: it increases consumption by 1 to 7% depending on climate, vehicle and use (ADEME).

Measure before you act

Each lever starts from a baseline: each vehicle's consumption in liters per 100 km, matched against its fuel card statements. A gap between the fuel paid for and the kilometers driven points to a driving, maintenance or fraud problem. Start with the lever where the gap is largest.

How Dadycar helps

Fuel consumption tracking brings together cards by supplier, the history of fill-ups and charging sessions, and fuel level and fuel theft alerts. The fuel card connectors import transactions from your suppliers and detect consumption anomalies.

Driver tracking calculates an eco-driving score and flags risky behavior, within the framework set by the CNIL. Due-date reminders warn you before each service.

Frequently asked questions

Which lever should come first?

Often driving, because it does not require changing vehicles. In town, aggressive driving uses up to 20% more fuel than smooth driving (ADEME). It takes trip tracking and driver training.

Does tire pressure really make a difference?

Yes. Under-inflation by 0.3 bar increases consumption by 1.2%, and by 2.4% at 0.5 bar (ADEME). A monthly check with cold tires is enough to avoid it.

How do you spot a vehicle that uses too much fuel?

Compare its consumption per 100 km with vehicles of the same model and the same use. Fuel card statements matched against mileage bring the gaps to light.