DNVT Driving Theory cheat sheet

Red circular border = prohibition; blue circle = mandatory instruction; yellow/amber diamond = warning in most jurisdictions.

Octagon is reserved for STOP only; inverted triangle is reserved for GIVE WAY/YIELD only - shape alone identifies the sign at a distance.

Steady red = full stop before the stop line; flashing red = stop then proceed when clear; flashing amber = proceed with caution, yielding to pedestrians.

A green light does not confer right-of-way; it only permits movement subject to yield rules, signals from a Garda/officer, and lane markings.

Broken white centre line = crossing permitted when safe; continuous white line = no crossing except to avoid an obstruction.

Double yellow lines along the kerb = no parking at any time; single yellow = no parking during posted times.

Zig-zag white lines near pedestrian crossings prohibit parking and overtaking within the marked zone.

Yellow box junction: do not enter unless the exit is clear, except when turning right and blocked only by oncoming traffic.

Signs with a red diagonal slash through a symbol cancel the restriction at that point (end of restriction).

At an uncontrolled junction the general rule is yield to traffic approaching from the right; at a T-junction the road ending yields to the through road.

Turning right: yield to oncoming traffic going straight or turning left; turning left: yield to pedestrians crossing the road you are entering.

A vehicle already committed to a roundabout has priority over vehicles entering; entering traffic yields to traffic from the left (in left-hand-drive jurisdictions, from the right).

Overtake on the right by default; overtaking on the left is permitted when the vehicle ahead is signalling a right turn or in slow-moving lane queues.

Safe overtaking gap: return to the lane only when the overtaken vehicle is fully visible in the interior mirror.

Two-second following rule in dry conditions; double to four seconds in rain, and at least four seconds at night or on gravel.

Stopping distance rises with the square of speed: doubling speed roughly quadruples braking distance.

Never stop or park within 5 m of a junction, within 15 m of a pedestrian crossing, or on a footpath, cycle lane or bus stop clearway.

Motorways: no pedestrians, cyclists, learners (unless accompanied per national law), or vehicles incapable of a minimum speed.

System of car control: Mirrors → Signal → Manoeuvre, with position and speed set before the hazard is reached.

Observation cycle: mirrors every 5–8 seconds on the open road; a shoulder (blind-spot) check before any lateral movement.

Two-second gap is the minimum; the only correct response to a tailgater is to increase the gap ahead, not brake-check.

Defensive rule: assume the other road user has not seen you until eye contact or a clear yielding action confirms it.

Hazard perception: scan 12–15 seconds ahead in urban areas and further at speed; look for brake lights two or three vehicles ahead.

Fatigue: after 2 hours of continuous driving take a 15-minute break; the only cure for drowsiness is sleep, not fresh air or coffee.

In fog use dipped headlights and fog lamps only when visibility is under about 100 m; switch fog lamps off when visibility improves.

Vulnerable road users: give cyclists at least 1 m clearance at up to 50 km/h and 1.5 m above that; pass horses wide and slow.

ABS prevents wheel lock and preserves steering; in an emergency brake firmly and hold, do not pump the pedal.

ESC/ESP detects understeer or oversteer and brakes individual wheels; it cannot exceed the grip available from the tyres.

Tread depth legal minimum is 1.6 mm across the central three-quarters of the tyre around its full circumference; replace at 3 mm for wet safety.

Tyre pressures are checked cold; under-inflation raises rolling resistance, heat and the risk of a blowout, and increases fuel use.

Engine braking on a long descent prevents brake fade; do not ride the brakes downhill.

Aquaplaning: ease off the accelerator, hold the wheel straight, do not brake sharply; grip returns as speed drops.

Skid recovery: release the brake, steer where you want to go, and avoid sudden inputs until the tyres regain grip.

Warning lights: red = stop safely and investigate; amber = caution, check at the next opportunity; blue/green = system active.

Indicate in good time and cancel the indicator after the manoeuvre; a signal does not give priority.

Do not use the horn except to warn of danger; it is prohibited in built-up areas at night in many jurisdictions.

Flash headlights only to warn of your presence, not to assert priority or to signal another driver to proceed.

Thank other drivers only with a brief hazard-light flash or a wave, and only when it is safe.

Keep left (or right, per jurisdiction) except when overtaking; do not hog the middle or outer lane.

At a merge, alternate one-for-one (zipper merge) where traffic is slow; do not block the merging lane.

Dip headlights for oncoming traffic, cyclists and pedestrians, and when following within about 100 m.

Do not splash pedestrians or cyclists; slow down and give clearance at puddles.

Alcohol slows reaction time, narrows attention and impairs judgement of speed and distance before any legal limit is reached.

The body eliminates alcohol at roughly one standard drink per hour; coffee, food and cold air do not speed this up.

A common legal limit is 50 mg per 100 ml blood (22 µg per 100 ml breath); lower limits apply to learner and novice drivers.

A hangover can leave alcohol in the blood; the morning after a heavy night can still be over the limit.

Prescription and over-the-counter medicines can impair driving; check the label and ask the pharmacist.

Illegal drugs and impairing medicines are offences regardless of measured concentration where impairment is shown.

Medical fitness: notify the licensing authority of conditions affecting driving (epilepsy, vision, diabetes with hypoglycaemia, heart conditions).

Minimum eyesight standard is typically a visual acuity of 0.5 (6/12) with or without correction, plus an adequate field of vision.