Adverse Conditions and Driver Fitness

Everything steals time or distance

This part of the course looks like two lists to memorise. One is weather and light: fog, ice, snow, rain, strong wind, darkness, low sun. The other is the driver: tiredness, alcohol, drugs, illness, strong emotion, eyesight. They are the same problem. Almost everything that makes driving dangerous works by stealing one of two things. Rain, ice and worn tyres lengthen the DISTANCE a vehicle needs in order to stop. Fog, darkness and low sun shorten how far ahead anything can be SEEN. Tiredness, alcohol, illness and strong emotion lengthen the TIME between noticing something and doing anything about it. ⭐ And only one thing gives any of it back: SPACE. More room to the vehicle in front and a lower speed buy back both the seeing and the stopping, which is why the sensible response to almost every item on both lists turns out to be the same response. So carry one question through the whole module: what has this taken away, time or distance, and how do I give it back? How far a vehicle actually travels while stopping is arithmetic, and it belongs to another module on this course.

Five words used exactly

Two of these are commonly used loosely, and one of them is a legal term with a precise meaning that is worth having.

Two that do not feel dangerous

Five driving conditions. Tap the TWO that most people do not slow down for, even though they should.

• Torrential rain with standing water across the road
• Bright low sun straight ahead on a clear winter morning
• Heavy falling snow that is settling
• The first few minutes of light drizzle, after a fortnight of dry weather
• Thick fog reducing visibility to a few car lengths

The driver who says they are fine

Somebody has been awake since very early and is driving home. They say they feel a bit tired but are fine to continue. Why is that judgement particularly unreliable?

• Because the thing being impaired includes the judgement about whether they are impaired, so a tired person is the worst available assessor of a tired person
• Because people usually lie about being tired
• Because there is a legal limit on how long anybody may drive
• Because tiredness can always be fixed with caffeine or fresh air

Two things a condition can take

Sorting a condition into one of these two columns tells you what it is doing, and both columns have the same remedy, which is the useful part.

Five conditions, five different things taken

As conditions worsen

Conditions deteriorate on a journey. Put the adjustments in the order they make sense.

• Notice that conditions have changed, which is the step most often missed
• Reduce speed, because everything else is easier at a lower one
• Increase the gap to the vehicle in front, so there is time to use
• Use lights appropriately, so you can see and, just as importantly, be seen
• Make steering, braking and acceleration gentler, so less is asked of the available grip
• If it is still not manageable, stop somewhere safe and wait

Four things stated accurately

On alcohol and drugs: there is a legal limit, it is set in law, and it is not the same everywhere in the United Kingdom. The figure is not the useful part and would be wrong for some readers anyway. The part that is true everywhere is that impairment begins well below any limit, so being under one is not the same as being unaffected. On medicines and illness: this is a question for a doctor or a pharmacist, who will say whether something affects driving. Nothing in a revision module can tell anybody what any medicine will do to them. On age and disability: fitness to drive is assessed individually, and it is about specific capacities at a specific moment rather than about groups of people. Vehicle adaptations are common and effective, and a great many disabled people drive. The honest version of this topic is about conditions and capacities, never about categories. ⭐ On colour vision: a colour vision deficiency does not stop anybody driving. Road signs are designed to be told apart by SHAPE AND POSITION as well as by colour, which is good design rather than a concession, and it is exactly what makes them still readable in fog, in low sun and at dusk for everybody.

What does each one take

For each factor, decide what it mainly takes away. Three lives.

Your own stairs in the dark

Think about coming downstairs in your own house at night without putting the light on. Almost everybody does it, and almost nobody thinks about it. It feels completely safe, and that is exactly the problem. You know those stairs. You have used them thousands of times. So you come down at your normal speed, without a hand on the rail, thinking about something else entirely. Now put one unexpected thing on the fourth step. A bag somebody left there. In daylight you would step round it without registering it. In the dark, at normal speed, with your mind elsewhere, the first you know about it is your foot arriving. Nothing about the stairs changed. What changed is how late the news arrives. ⭐ And notice what somebody does in an unfamiliar house: slower, one hand out, feeling for each step. Not because those stairs are worse, but because they know they are not going to get early warning. That is the whole adjustment, and it costs about four seconds.

What actually gives time back

Conditions have worsened on a journey. Select every action that genuinely reduces the risk rather than only feeling as though it does.

• Increasing the gap to the vehicle in front
• Reducing speed
• Making steering and braking gentler
• Gripping the wheel harder and concentrating more fiercely
• Turning the radio up to stay alert

Finish the conditions sentences

When a layer of water builds up between a tyre and the road so that the tyre is no longer touching it, that is _____, and steering and braking do very little until contact returns. How easily other people can see you, which is mostly within your own control, is your _____. Any reduction in the ability to drive safely, from any cause, is _____, and it is a state rather than a type of person. Whether somebody is in a condition to drive safely at this moment is their _____ to drive, and where a medical condition is involved that is assessed individually by qualified people. What you can see to the sides while looking ahead is your _____ vision, and it narrows as speed rises. Almost every condition on this topic is taking away either time or distance, and the single thing that gives either of them back is _____.

Build the explanation

A question asks why light rain after a long dry spell can be more dangerous than heavy rain. Assemble the answer.

One journey, four decisions

A driver is making a familiar journey home. Each stage sets out what has changed and hands you the decision.

• It begins to drizzle after a fortnight of dry weather. The road looks barely wet. Decide.
• The sun drops low and comes straight down the road ahead. For a few seconds almost nothing is visible. Decide.
• The driver has been awake since very early and notices they have no memory of the last few miles. Decide.
• A friend says they only ever drive after a drink if they are under the limit, so there is nothing to discuss. Decide what to say.

Explain the one idea

Explain why weather conditions and the driver's own condition, which look like two separate topics, are really one problem.

• State what almost every condition on both lists takes away
• Give ONE weather condition and say which of the two it takes, and why
• Give ONE driver condition and say which of the two it takes, and why
• Explain why the response to almost all of them turns out to be the same
• Explain why some of the most dangerous conditions are ones drivers do not slow down for
• Finish by explaining why a tired driver is a poor judge of whether they are too tired