I noticed an argument about eco-driving and overuse of the brakes, which is descending into a technical duel of opinions and misconceptions.
Ecosafe driving is a style of driving that is both safe and economical, and this is perceived as being good for the environment. The backbone of ecosafe driving is to plan ahead and know as much about what is happening around you as is possible (without compromising safety, of course). That way you can react early to situations.
Late braking and harsh acceleration are bad techniques – they always have been – and are not part of the ecosafe approach. As Driving: The Essential Skills (TES) says, these tend to increase fuel consumption. Note the word “tend”.
The reason for this is quite simple. It is pushing the accelerator (gas) which primarily affects how much fuel is used, so obviously pushing it hard and to excess (or for longer than needed) is clearly going to use a lot more gas. Harsh acceleration is therefore wasteful.
As for harsh braking, it isn’t the act of braking itself that is the problem – you don’t use more gas just by using the brake. However, if you accelerate to an unnecessary speed (which uses more gas), slamming the brakes on just wastes all that effort. So harsh braking doesn’t use gas, but it does waste it.
Of course, the whole attitude underpinning this chavvy style of driving is also likely to be increasing fuel consumption as well, so it’s a vicious circle.
As a rough guide, ecosafe driving is:
- driving away smoothly without harsh acceleration
- turn off your engine when safe and convenient (if you’re waiting more than a minute or two)
- accelerate smoothly and gently
- when safe and convenient, take your foot off the gas and use the car’s momentum to maintain speed
- miss out gears when possible (block changing) as it requires shorter acceleration times (if done properly)
- use the highest gear possible without making the engine strain
- use engine braking when you can
There’s much more to it, but these are the ones which a driver has continual control over because it is part of their overall style.
You cannot avoid driving up hills, and if you were always going up them then your fuel consumption would be high. The best ecosafe method is to use gravity – and the brakes to stay within the limit using an appropriate gear – going downhill, and use momentum plus gentle gas in the appropriate gear going up.
You can’t get 100mpg going up a steep hill, and not being able to do so does not make you a poor ecosafe driver. Trying to do it in 5th gear would, though.