Driving Tips to Save Fuel

From www.greatdriver.co.uk: "Always try and use the vehicle controls as smoothly as possible, with particular attention to:

• starting and moving away
• accelerating
• using gears
• driving at an appropriate speed

This reduces wear and tear on your vehicle and will help in reducing CO2.
Planning
Reduce harmful emissions by anticipating road traffic conditions and acting in good time, rather than reacting to them at the last moment, especially:

• showing hazard awareness and planning
• making use of engine braking
• stopping the engine when appropriate

Tips for ‘eco-safe’ driving and riding
Follow these tips as a guide to safe driving or riding for economy:

• check your tyres regularly and keep at recommended pressure
• don’t carry unnecessary weight
• remove roof-rack or luggage boxes when not needed to reduce air resistance
• don’t exceed speed limits
• accelerate briskly
• consider using cruise control where it would be appropriate
• turn off your engine if you’re likely to have a prolonged wait
• use air conditioning only when you need to
• plan your route to avoid known congestion points
• try to travel during off-peak times

Further information on eco-safe driving and riding is available in leaflet ‘Eco-Safe Driving - a guide to safe driving/riding for economy’."

One aspect of vehicle acceleration that is counter-intuitive until it is correctly explained is this: your engine is at its most efficient when the throttle is wide open, because the "throttle" is there to starve the engine of air, such as when the engine is idling, i.e. the engine is running in its least efficient state.
When you put your foot on the accelerator it uses more fuel, but the engine is at its most efficient, so the idea is to accelerate briskly until you reach the desired speed, and then change to a high gear so it uses the least amount of fuel. Obviously accelerating too fast puts strain on the car, but accelerating too slowly uses extra fuel, because you are accelerating and the throttle is partially closed so the engine is not being efficient.
So if you accelerate rapidly for a short period of time the engine is being used efficiently and you aren't using up too much fuel. Weird, but true.