How Aggressive Driving Wastes Fuel: What the US Government Data Says
The numbers
The US Department of Energy and EPA site fueleconomy.gov says aggressive driving, meaning speeding, rapid acceleration and braking, wastes gas. It can lower gas mileage by roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic.
Speed
Each vehicle reaches its best fuel economy at a different speed, but fueleconomy.gov says gas mileage usually decreases rapidly at speeds above 50 mph (about 80 km/h). It adds that observing the speed limit is also safer.
Driver feedback
The same page says driver feedback devices can help you drive more efficiently. A study it cites suggests they help the average driver improve fuel economy by about 3%, and those who use them specifically to save fuel can improve gas mileage by about 10%.
Practical habits
- Accelerate smoothly and look ahead so you can ease off instead of braking hard.
- Keep a steady speed on open roads.
- Sensible driving is also safer for you and others, so you may save more than fuel money.
A caution
These are US government figures from vehicles and roads that differ from Sri Lankan conditions. Treat the percentages as a range to expect rather than a promise for your own car.
Fact-checked on 30 October 2026 against the sources listed below. Tax rules and prices change by gazette, so confirm with Sri Lanka Customs or the Ministry of Finance before you pay.
Frequently asked questions
How much fuel does aggressive driving waste?
Roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic, according to fueleconomy.gov.
At what speed does fuel economy fall quickly?
Usually above 50 mph, though each vehicle differs.
Do fuel-saving devices work?
A study cited by fueleconomy.gov suggests driver feedback devices help the average driver by about 3%, and about 10% for those using them to save fuel.