Texas Driver Handbook 2017

Appendix A: Glossary of Terms 

Texas Driver Handbook

- H -

hallucinogen – mind-altering drug that tends to distort a person’s perception of direction, distance, and time

hazard flasher – a device that flashes front turn signal lights and taillights to warn others the vehicle is a hazard

head restraints – specially designed air bag or padded devices on the backs of front seats helping to reduce whiplash injuries in a side or 

rear impact collision

highway hypnosis – drowsy or trance-like condition caused by concentration on the road ahead and monotony of driving

hydroplaning – occurs when a tire patch loses contact with the road by rising up on top of water

highway – the width between the boundary lines of a publicly maintained way any part of which is open to the public for vehicular travel 

- I -

ignition interlock device – a special mechanical control device installed on a motor vehicle’s dashboard. A driver must exhale into the de-

vice to start the vehicle. The court-ordered installation of an interlock ignition device must be performed by a DPS-certified service center

implied-consent law – anyone who receives a driver license automatically consents to be tested for blood-alcohol content and other drugs 

if stopped for suspicion of alcohol or drug usage while driving

intoxilyzer – the breath-test instrument machine commonly used for determining blood-alcohol content

- J -

- K -

- L -

lane change – lateral maneuver moving the vehicle from one lane to another using proper space management procedures

lane signal – a signal, usually overhead, indicating if a lane can or cannot be used at a specific time

liability insurance – provides compensation for damages which the insured is legally obligated to pay; covers others when you are at fault

light truck – a truck with a manufacturer’s rated carrying capacity of not more than 2,000 lbs., including a pick up truck, panel delivery 

truck, and carry-all truck

limited use lanes – traffic flow lanes posted and designed to accommodate special vehicles or carpools

- M -

median – area of ground separating traffic moving in opposite directions

merging area – stretch of road at the end of an acceleration lane on an expressway where vehicles join the flow of traffic

minimum speed limit – speed limit to keep traffic moving safely by not allowing drivers to drive slower than a certain speed

moped – a motor-driven cycle that cannot attain a speed in one mile of more than 30 mph and the engine:

1.  Cannot produce more than two-brake horsepower; and

2.  If an internal combustion engine, has a piston displacement of 50 cubic centimeters or less and connects to a power drive system that 

does not require the operator to shift gears. Two-wheeled vehicle that can be driven with either a motor or pedal.

motorcycle – a motor vehicle, other than a tractor, equipped with a rider’s saddle and designed to have when propelled not more than three 

wheels on the ground

motor-driven cycle – a motorcycle equipped with an engine displacement of 250 cubic centimeters or less. The term does not include an 

electric bicycle

- N -

night blindness – not being able to see well at night

no-fault insurance – covers an insured’s losses and expenses associated with a collision regardless of fault

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Appendix A: Glossary of Terms 

Texas Driver Handbook

- O -

odometer – the device on the instrument panel indicating the total number of miles the vehicle has been driven 

over driving headlights – driving at a speed making your stopping distance longer than the distance lighted by your headlights; low beams 

are limited to 45 mph and high beams are limited to 65 mph for stopping purposes

oversteer – when the rear tire patches lose varying degrees of traction and the front tire patches have more traction causing a spinning 

effect (yaw) around the vehicle’s center of gravity. The vehicle has a tendency to spin to the left or right even though the driver is not 

turning the steering wheel

overtake – to pass the vehicle ahead

over-the-counter medicine – drug that can be obtained legally without a doctor’s prescription

- P -

parallel parking – the vehicle lines up parallel or going the same direction as the curb. When parallel parking, the vehicle must be 6 to 18 

inches from the curb

passive restraint device – a restraint device, such as an air bag or an automatic safety belt, that works without the passenger or driver 

initiating the device

pedestrian – a person on foot

pedestrian signal – a signal used at traffic intersections that indicates when a person should walk or wait 

peer pressure – mental and social influence of others of a similar age on decision-making skills 

perception distance – the distance your vehicle travels during perception time

perception time – the length of time it takes for the driver to make a risk-reduction decision

peripheral vision – the area a person can see that is around the central field of vision

perpendicular parking – the vehicle is parked at a right angle to a curb or parking stripe using visual reference points for entering and 

leaving

prescription medicine – drug that can be purchased legally only when ordered by a doctor

preventive maintenance – routine care and attention to your vehicle

property-damage insurance – protects the driver who is at fault against claims for damages to another person’s property, up to specified 

limits

protected left turn – left turn made on a left-turn, green arrow, or delayed green light while oncoming traffic is stopped

protective gear – the items a motorcyclist wears to protect head, eyes, and body

- Q -

- R -

race – the use of one or more vehicles in an attempt to:

1. Out gain or outdistance another vehicle or prevent another vehicle from passing;

2. Arrive at a given destination ahead of another vehicle(s); or

3. Test the physical stamina or endurance of an operator over a long-distance driving route

reaction distance – the distance a vehicle travels from the point the driver perceives the need to act and the point where the driver takes ac-

tion through braking, steering, or acceleration. Distance your vehicle travels until the driver perceives the need to change speed or position

reaction time – the time the vehicle travels from the point the driver perceives the need to act and the point where the driver takes the 

action through braking, steering, or acceleration. Length of time it takes the driver to execute a reduced-risk action, after a response is 

perceived by the driver

reduced visibility – the inability of a driver to see clearly

reference point – a part of the outside or inside of a vehicle, as viewed from the driver’s seat, that relates to some part of the road which 

allows the driver to estimate position on the road. The road positions (points of reference) of the vehicle assist the driver in determining 

when to start turning, vehicle limitations, or where the vehicle is actually located

regulatory sign – a sign controlling traffic

restraint device – any part of a vehicle holding an occupant in the seat during a collision

restricted interlock license – authorizes an individual to operate a motor vehicle equipped with an ignition interlock device

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