DGT Glossary 2026
Key driving theory exam terms, explained in plain language. Each entry includes a definition, key facts and an exam tip.
Adaptive lights
Headlight system that adapts beam shape or intensity to road conditions.
Anti-lock braking system (ABS)
Electronic device that prevents the wheels from locking up during emergency braking.
Bike lane
Lane or path reserved for bicycles and, in some cases, personal mobility vehicles (PMVs).
Blind spot
Area around a vehicle that the driver cannot see using the mirrors.
Blood alcohol limit
Concentration of alcohol in blood or exhaled air, expressed in grams per litre.
Braking distance
Distance the vehicle travels from the moment the brake is pressed until it stops.
Broken line
Dashed white longitudinal road marking that may be crossed.
Bus lane
Lane reserved for bus traffic, sometimes shared with other authorised vehicles.
Central reservation
Longitudinal area that physically separates the two carriageways of a motorway, dual carriageway or expressway.
Centrifugal force
Apparent force that pushes a vehicle outwards in a curve.
Child restraint system (CRS)
Type-approved seat or device that adapts the seat belt to children under 1.35 m tall.
Conventional road
Interurban road that is not a motorway, dual carriageway or expressway.
Default speed limit
Speed limit applied by default to each road type when no sign says otherwise.
Driver drowsiness
State of sleepiness in the driver that reduces attention and reaction time and multiplies crash risk.
Driving licence points
Penalty system for serious or very serious offences that reduces an initial point balance on the licence.
Dual carriageway
Fast road with separated carriageways per direction and at least two lanes each way, no at-grade intersections.
ESP (electronic stability control)
Electronic system that detects lateral skidding and corrects it by braking individual wheels.
Fog lights
Special lights to improve visibility (yours and others') in fog, heavy rain or snow.
Hard shoulder
Longitudinal strip of the road outside the carriageway, separated by a road marking.
Hi-vis vest
Mandatory high-visibility garment the driver must put on before leaving the vehicle on interurban roads.
High beams
Long-range front lights that illuminate about 100 metres ahead of the vehicle.
Level crossing
At-grade crossing between a road and a railway line.
Low beams
Short-range front lights that illuminate the road without dazzling other drivers.
Low-emission zones (LEZ / ZBE)
Urban areas where vehicle circulation is restricted or banned based on the DGT environmental sticker, to reduce pollution.
Minimum speed
Speed below which you may not drive without obstructing other traffic, except for justified causes.
Moped
Two or three-wheeled vehicle with engine displacement ≤50 cc and a top design speed of 45 km/h.
Motorway
Top-grade public road with separated carriageways, no direct property access, restricted to motor vehicles.
Overtaking
Manoeuvre of passing another vehicle going the same direction, temporarily using the opposing lane or a free lane.
Pedestrian crossing
Marked zone of the road for pedestrians to cross, where they have priority over vehicles.
Reaction time
Time from when the driver perceives a hazard until they act on the controls.
Reflector (catadioptric)
Passive reflective device that bounces incoming light back toward its source so it can be seen in the dark.
Reversible lane
Lane whose direction of travel can change according to time of day or traffic demand.
Right of way
Rules that decide which vehicle or road user goes first when several converge at an intersection or manoeuvre.
Road marking
Lines, symbols or text painted on the pavement that regulate or inform traffic.
Roundabout
Circular intersection where vehicles already on the ring have priority over those entering.
Safe following distance
Gap a driver must keep from the vehicle in front to stop without colliding.
School zone
Section of road near a school, signposted and with reduced speed limits.
Seat belt
Mandatory restraint system that keeps the occupant in their seat during a collision.
Semi-trailer
Trailer without a front axle, coupled to a tractor unit so part of its weight rests on the tractor.
Solid line
White longitudinal road marking that may not be crossed or stepped on.
Stop sign (R-2)
Red octagonal sign with the word «STOP» requiring a full stop before the intersection.
Tachograph
On-board device recording driving time, rest periods and speed for heavy and professional vehicles.
Town-crossing road
Section of an interurban road passing through the built-up area of a town.
Traffic light
Luminous device regulating traffic with red, amber and green lights, overriding any other signage except a traffic officer.
Tyre pressure
The internal air pressure of tyres, set by the manufacturer, that drives behaviour, fuel use and safety.
V-16 emergency beacon
DGT-approved luminous beacon that replaces warning triangles to signal an immobilised vehicle.
Vehicle technical sheet (ITV card)
Official document listing the vehicle's technical specs and inspection history.
Vertical signage
Signs mounted on posts or overhead gantries beside or above the road.
Warning triangles (V-12)
Portable triangular signs placed in front of and behind an immobilised vehicle to warn other drivers.
Yield sign (R-1)
Inverted triangular sign requiring you to give way to traffic on the road you're joining, without stopping if no traffic is coming.