Roadcraft Definitions Flashcards
What is the system of car control?
The system of car control is a way of approaching and negotiating hazards that is methodical, safe and leaves nothing to chance. It involved careful observation, early anticipation and planning, and a systematic us of the controls to maintain your vehicles stability in all situations.
The system of car control increases your safety in a constantly changing driving environment by giving you time to react to hazards.
Tug?
Take. Use and Give Information.
The purpose of the plan?
To put you…
In the correct position
At the correct speed
With the correct gear engaged
At the correct time
In order to negotiate hazards safely and efficiently
Safe stopping distance rule
Always drive so you can stop safely within the distance you can see to be clear on your own side of the road
When is a moving vehicle most stable?
When it’s weight is evenly distributed, it’s engine is just pulling without increasing road speed, and it is travelling in a straight line.
The tyre grip trade off
If more tyre grip is used for braking or accelerating, there is less available for steering. And view versa.
What affects the tyre grip?
Braking, steering and accelerating alter the vehicles balance and tyre grip
Acceleration sense
The ability to vary vehicle speed in response to changing road or traffic conditions by accurate use of the accelerator, so that you use the brakes less or not at all.
This uses less fuel, causes less wear on the tyres and reduces carbon emissions
Why is the main effect of the gears?
To transform engine revs into usable power
Low gears have greater turning power which affects tyre grip.
The greater the turning power the more likely that the tyres will lose grip.
In slippery conditions use a higher gear so you have more tyre grip
Why shouldn’t you change gear when cornering?
It destabilises the vehicle and requires you to take one hand off the steering wheel
Advantage to abs?
It gives you some steering control during emergency braking. It helps steering while braking.
Accurate steering requires?
Good observation, anticipation and planning
What does the limit point give you?
A systematic way of judging the correct speed to use through a bend
What is the limit point?
The furthest point to which you have an uninterrupted view of the road surface
This is where the right hand edge of the road appears to meet the left hand edge in be distance
Where is thelimit point on a left hand bend?
Where the edge of the road meets the central white line (or centre of the road if no white line)
What are the factors that affect/determine your vehicles ability to corner?
The specification as condition of the vehicle, inc tyres
Your speed
The amount of steering you apply
The amount of acceleration or braking
The slope across the road surface (camber and super elevation)
The road surface and how the weather has affected its grip
How does a camber affect your steering on a left hand bend?
It increases the effect of your steering as the road slopes down in the direction of the turn
How does a camber affect your steering on a right hand bend?
If reduces the affect of steering as he road slopes away from the direction of the turn
What is super elevation?
Where the whole width of the road is banked up towards the outside edge of the bend, making the slope favourable for cornering in both directions
What are the principles of cornering?
Make sure the vehicle is in the correct position on the approach to the corner
Travel at the correct speed for the corner
Be in the correct gear for that speed
Use the accelerator to maintain a constant speed through the bend
Be able to stop safely in the distance you can see to be clear on your own side of the road
What is the following position?
2 second rule
Keep a safe distance behind the vehicle in front of you
How does distance (2 second rule) increase your safety?
Gives you a good view of what is happening on the road ahead - you can increase your vie walking both sides by a slight change of position
You can stop your vehicle safely if the driver in front brakes firmly without warning
You can extend your braking distance so that the driver behind has more time to react
You can see when it’s safe to move into overtaking position
In wet weather you get less spray from the vehicle in front
Front wheel and rear wheel drive - how can affect steering?
Front wheel drive - under steer (tendency to turn less)
Rear wheel drive - over steer (tendency to turn more)
…In response to a given turn of the steering wheel.
Tiredness - when do our reactions tend to be slower?
In the morning
Between what times is the greatest risk of tiredness related collisions?
11pm - 6am
When should you use fog lights?
When visibility is reduced to 100 metres or less
When overtaking at night, when should you put on full beam?
When you are alongside the vehicle you are overtaking
How can you reduce dazzle from oncoming cars headlights at night?
Look towards the nearside edge of the road and reduce your speed.
If you are dazzled then slow down or stop if necessary
What can help you identify curves and the direction of the curves in the road at night?
Roadside market posts that reflect off your headlights
Reflective studs in the road
cats eyes - the more cats eyes there are in the centre of the road, the more hazardous the road
White paint - the more paint the more hazardous the road is.
Brake lights on the vehicle in front of you
How do different cats eyes spacing differ in central white line markings?
Centre lines - one cats eyes spaced in every other one
Hazard lines - one cats eye in every gap
Double white lines - twice as many cats eyes as there are in hazard lines
What is a micro climate?
Areas where frost or wet patches can linger even when they have disappeared elsewhere..
Ie
- Valley bottoms
- Areas of shadow cast by trees or buildings
- Shaded hillsides or slopes
- Bridge surfaces (as they are exposed on all sides)
- patchy fog
On road signs with more than 1 hazard sign on them, which is the hazard closest to you?
The one at the top
OUR - making best use of road signs?
Observe
Understand
React
Observation links:
Cluster of lampposts?
Single lamppost ?
No gap in bank of trees ahead?
Cluster - probable roundabout ahead
Single - look out for exit point of a junction
No gap in trees - look out for road curve to left or right
Driving smoothly can reduce fuel consumption by?
15%
And it reduces wear and tear
Control of your vehicle is dependant on what?
The grip between your tyres and the road
Tyre pressure can affect what
Stability - under inflated tyres defect stability and also increases rolling resistance and fuel consumption
What is tyre grip trade off?
If more tyre grip is used for braking then there is less available for steering and vise versa.
The patch of tyre is contact with the road is about the same size as a hand (this can vary with size of vehicle and width of tyres)
What affects the load between the wheels and therefore the vehicles balance?
Braking steering and accelerating
When cornering /braking /accelerating etc where does the weight of the vehicle shift to?
The outside of the curve
If cornering and braking then the weight shifts to the outside of the curve and to the front
If cornering and accelerating the weight shifts to the outside of the curve and to the back
Accelerating - weight shifts to back
Braking - weight shifts to front
Definition of acceleration sense?
The ability to vary vehicle speed in response to changing road or traffic conditions by accurate use of the accelerator, so that you use the brakes less or not at all.
This uses less fuel, causes less wear and tear in tyres and reduces carbon emissions
What happens to our speed if you keep the same pressure on the accelerator as you go into an around a bend?
You will lose road speed
When should you use maximum acceleration through the gears?
If there is a pressing need and if the road surface and conditions are safe
Low gear = ? revs / speed?
High gear = ? Revs / speed?
Low gear - Engine can rev more freely, allowing vehicle to accelerate rapidly and climb slopes. Also restrains speed when descending a slope.
High gear - lower revs deliver more speed but less ability to accelerate or climb slopes
Intermediate gears allow progress from one extreme to the other
How does the greater turning power of low gears affect tyre grip?
The Greater the turning power the more likely the tyres will lose grip
High or low gear for slippery conditions?
High
When does engine braking (using acceleration sense) allow you to lose speed in conditions where normal braking might lock the wheels?
On slippery roads.
It is also useful on long descents
What should normal braking be?
Progressive and increased steadily
Tapered braking ?
Gently take up the initial free movement of the pedal
Increase the pressure progressively as required
Relax pedal pressure as road speed is lost
Release pedal just before stopping to avoid jerking
Stopping distance you should allow on narrow and single track lanes?
Twice the overall distance you can see to be clear
Overall stopping distance?
Thinking distance + braking distance
Thinking distance?
The distance travelled in the time between first observing the need for action and acting.
Actual thinking distance varies according to speed of vehicle, your physical and mental condition, your attentiveness and whether or not you are expecting something to hAppen.
Ou need less thinking time if you are what ?
Anticipating events and not just reacting to them
Braking distance ?
The distance you need for braking.
Braking distance depends on?
Vehicle capability, size and weight,
The gradient of the road and the condition of the road surface
What causes a skid?
Excessive speed
Coarse steering
Harsh acceleration
Excessive/sudden braking
Ie: the driver!
How does a skid happen?
When one tyre it more loses grip on the road , causing an involuntary movement of the vehicle.
This happens when the grip of the tyres on row becomes less than the force or forces acting on the vehicle
Minimise skidding?
Check tyre tread and pressure
Check vehicles brakes
Avoid skidding by using observation, anticipation and planning to adjust your driving when road surface may be slippery
Anticipate and plan - adjust your driving to the be road conditions… How?
Leave plenty of room for manoeuvre
Reduce your speed
Increase the distance you allow for stopping to match the road conditions
Use lower revs in slippery conditions to avoid wheel spin and Use higher hear when travelling at low speeds
Use principles of cornering to negotiate corners carefully
Aim to take, steer and change he’s as smoothy as possible so not to brake tyre grip
Weight in the boot will alter a vehicles normal balance and tyre grip
.
How can you increase understeer in a front wheel drive car?
Enter bend too fast
Apply too much power in bend
Steer too sharply
You can reduce this by reducing power and / or steering
Traction control?
Controls excess wheel spin on individual wheels. Applies independent braking to the spinning wheel.
Allows you to make max use of tyre grip (eg where one wheel can grip surface as normal but another slips on ice or snow)
ESP?
Incorporates conventional abs and traction control systems.
Designed to help vehicle stability by detecting when vehicle is driven to limit of its capabilities
Sensors at each wheel and a sensor that monitors the checkers rotation and pitch.. Another sensor on steering detects drivers intended path and If they sense that the vehicle is not following the intended path the system will intervene - applying brakes to individual wheels in order to correct any under it over steer.
It is crucial that you steer in be direction you want to go!
Single track lane with passing places - who has right of way?
Those travelling uphill
3 types of hazard
- Physical features (or roundabouts, junctions etc)
- The position or movement of Other road users
- Weather conditions
Cadence
If not got abs on vehicle cadence is the action of pumping of brakes to help you to steer
Purpose of signals
Inform other road users of your presence or intentions
Give a signal whenever it could benefit other road users
Best position for approach to left hand junction?
Right hand junction?
Left turn - Middle of road
Right turn - towards centre line
If taking left junction that is sharp angled, obstructed view or pedestrian present, how approach corner
From further out than normal from as far back as possible
The greater the element of danger…
The higher priority you should give to it
What is the system?
The system of car control is a way of approaching and negotiating hazards that is methodical, safe and leaves nothing to chance. It involves careful observation, anticipation and planning, and a systematic use of the controls to maintain your vehicles stability in all situations
What is a double apex bend?
A bend which gets tighter as it goes round
Consider 3 things when positioning for cornering
Safety
Stability
View
What would you consider before overtaking?
Clear view ahead Sufficient space Absence of oncoming traffic Safe return gap Relative speed of your own vehicle and the vehicle you intend to overtake
At 70mph you travel 31 metres per second! The equivalent of 3 coach lengths
.
3 exemptions in law for response driving?
Excess speed limit
Contravene red light
Contravene a keep left/ right sign
Must be safe and proportionate to circumstances
What 4 things is the warning equipment primarily used for?
Provide advance warning to other road users
Help your progress through traffic
Protect officers are scene of incidents
Help in stopping motorists by identifying vehicle as a police vehicle
What is the best visual warning equipment in use in daylight?
Flashing headlamps
A roundabout is a one way system for which there is no exemption !
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What is a hazard?
Anything that is an actual or potential danger
