Driving smoothly has a number of benefits. It keeps your passengers more comfortable (especially children in the back seat), it puts less stress on the car, you use less fuel, in general it’s safer, and you can make more rapid progress down the road. Before we find out how to drive smoothly, let’s look in more detail about what problems erratic driving causes.
Passengers perceive g-forces more than drivers as they don’t have a steering wheel to hold on to and, if in the back, can’t always see where the road is turning, therefore can be surprised by a car’s movement.
Leaning into a curve tends to make travel more pleasant; being thrown around by unexpected curves, or having to brace yourself, doesn’t. If car sickness ensues, you’ll spend much longer getting to your destination.
Vehicle wear and tear
Greater g-forces mean more wear and tear on tyres, brakes and suspension components. Sharp turns load up the suspension and put more pressure through the tyres
Driving smoothly means anticipating braking and acceleration points, using appropriate acceleration and carrying more speed through corners without increasing the g-forces. As a result you’ll use less fuel.
Less margin for error
Even though you may be travelling more slowly than you could theoretically drive, erratic and harsh movements give you less margin for error, particularly when the road conditions are more challenging such as in the wet. Greater g-forces equate to more chance of causing a skid.
Driving less smoothly is slower
When you drive more smoothly it often means you can make more rapid progress, and this is primarily because cornering technique will allow you to maintain a great speed through the corners, but without increasing the maximum g-force.
How do you drive more smoothly?
Look as far up the road as possible and this will allow you to see when corners are coming, and also if there are other vehicles that you might need to overtake or brake for. A really common occurrence is to see a driver zoom rapidly up to the rear of a car on the motorway and slam on the brakes as if they didn’t see them. This just uses up your petrol and brakes. Start slowing down slightly earlier and moderate your speed so that you catch up with the vehicle in front at a time when they are able to pull back into the left. Or, if you are in a place where you can’t overtake, there’s no reason to come barrelling up behind someone as you can catch them up gradually.
Anticipation can be used when approaching traffic lights. If the lights have been green for a while as you are approaching them, it’s likely they will turn red by the time you get there. Similarly, if they’ve been red a long time as you’ve been approaching, they could turn green. This is more effective if you know the road and the phasing of the lights.
Using the accelerator and brake correctly
You should only ever need the accelerator’s full travel in two situations: overtaking, or getting out of danger that requires you to speed up. You should only need your brake’s full potential if there is imminent danger that means you have to stop as quickly as possible.
If you are driving a manual car, make sure you are in the right gear for the amount of acceleration you need in relation to the speed you are going. If you are driving an automatic car then you will eventually learn how much you can push the throttle down before it kicks down a gear.
Taking the smoothest line
There are two main methods of cornering and there pros and cons to each method. The Institute of Advanced Motorists will teach you a slightly different way of cornering when you can’t see around the corner because of the ‘vanishing point’ (I’ll explain this in another post). Technically, the smoothest way around a corner is the racing line. This is best explained in a diagram (below). Approaching the corner you stay near the outside, i.e. if you’re approaching a right-hand bend, move to the left of the road. Brake mostly in a straight line. You can use a little trailing brake (very gentle braking) as you start to turn, and this will be necessary if the corner has a decreasing radius (i.e. gets sharper). Aim the car at the apex of the bend (but not crossing the centre line); ideally your inside wheels will be just to the left of the centre line. Then let it drift out towards the outside of the curve. With practice you will start to feel the smoothest line through the corner. Driving this line is the most gentle curve between the change in direction.
For a left-hand bend you will move to the right of your lane (don’t cross the centre line). The apex is on the inside of the corner. Try not to cross any edge lines as there may be rough patches, bumps or objects that could damage your tyres. Then let it drift out to the right hand of your lane. If there’s an approaching vehicle (particularly a heavy one), then you would not do this because you want to maintain a safety margin, but if there is no traffic it is safe to smooth out the corner.
This line creates the least stress on the car, the least g-forces and allows you to maintain a greater speed through the corner, thus saving fuel. It also gives you a better margin of error mid-corner.
The other benefit is that as you approach the bend from the opposite side of your lane (i.e. the left of your lane for a right-hand bend), you can actually see slightly further around the bend.
Taking the safest line
The IAM way of cornering will see you only brake in a straight line and turn in towards the apex only when you can see through the corner. You don’t cut as close to the centre line (or inside of the curve), and you drive into your lane directly rather than letting it drift out. This is safer when you can’t see through the corner, and on narrower roads. The car is also more stable under a small amount of throttle which will enable you to keep your speed constant around the corner.
Remember, it’s not what you drive, it’s how you drive it. A relatively thirsty car can still be driven in a manner that’s very smooth and efficient and perhaps will beat a frugal car driven by a bad driver. This segment on top gear (the second one in the video, regarding the Prius vs BMW M3) shows that – jump to 3:33.