Drivers Ed

Anti-lock braking system (ABS)

Prevents any of the wheels from locking during hard braking

Blood alcohol content (BAC)

The concentration of alcohol in the bloodstream as measured by a breathalyzer or another test

Blind spot

An area over your left or right shoulder that is not visible in any mirror

Braking distance

The distance it takes your particular car to stop once the brakes have been applied

Center of gravity

The point around which the vehicle’s weight is evenly distributed

Central vision

A five-degree cone of vision that provides detail of objects and conditions; used in targeting

Closed zone

Space not open to you because of a restriction in your line-of-sight or intended path-of-travel

Compromising

When faced with more than one hazard at the same time that cannot be separated, give as much space as possible to the one with the greatest risk.

Contact patch

The area of a tire that is actually in contact with the road

Controlled braking

Smooth, consistent application of pressure to the brake pedal

Creeping speed

The speed a car with an automatic transmission travels when in gear using idle acceleration with no pressure applied to the brake or accelerator

Danger Zone

The space 4 – 6 seconds ahead of your vehicle; this is the last opportunity to control your path of travel

Following Distance

The time or space between two vehicles traveling the same direction in the same lane

Fringe vision

The area surrounding one’s central vision; used to judge depth and position; gives information about objects close to the path of travel and reference points

Gap

A space between vehicles on a roadway

Ground viewing

Searching the visual scene near the ground to detect important information to support safe driving

Guide sign

Provides information about routes, exits and distances; also indicate points of interest, recreational and medical facilities, and roadside services, gasoline stations, lodging & restaurants; often rectangular and green, blue, or brown

Hand-over-hand steering

Pulling the steering wheel down with one hand while the other hand crosses over to pull the wheel down further

Hole

A space between two traffic clusters

Idle acceleration

In a car with an automatic transmission, using the idling of the engine to propel the car forward without pressure applied to the accelerator pedal

Implied consent

Anyone who receives a driver license automatically consents to be tested for blood-alcohol content and other drugs if stopped for suspicion of drug or alcohol use while driving

Inching speed

Very slow movement of the vehicle using idle acceleration and controlling speed with the brake pedal – literally moving inch by inch

Inertia

Newton’s 1st law of motion; The tendency of an object to resist changes in motion. An object in motion stays in motion at the same speed in the same direction until acted upon by another force. An object at rest stays at rest until acted upon by another force

Intersection

Any place where two or more roadways meet or cross

Inattention blindness

A type of cognitive distraction in which a driver’s brain does not process the information the eyes take in

Legal stop

Stop made at the stop line, crosswalk, implied crosswalk, or curb line as required by law

Light acceleration

To maintain slow forward motion or allow speed to increase with minimum weight shift

Line-of-sight

The imaginary line that extends from your eyes to the point of focus

Momentum

A measure of inertia; the amount of momentum an object is equal to its mass multiplies by its velocity

Open zone

Space where you can drive without a restriction to your line-of-sight or path-of travel

Path-of-travel

Space that your vehicle will occupy as you travel on the roadway toward the target area

Perception distance

The distance your car travels before you realize the need to brake

Peripheral vision

The area beyond one’s fringe vision; used to notices changes in light and shape; gives information about objects that could threats along one’s path-of-travel; strongly affected by drugs, fatigue, and high speed

Point of no return

Point beyond which a driver can no longer stop safely without entering an intersection

Progressive acceleration

Firm accelerator pressure used to increase speed

Protected left turn

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

Push-pull steering

A method of steering while turning where your hands pass the wheel from hand to hand and do not cross in front of the airbag

Reaction distance

The distance your car travels before your foot engages the brake pedal

Reference point

A point on the vehicle, viewed from the driver’s seat, that relates to some part of the roadway

Regulatory sign

Tells drivers what they may or may not do at a given time and/or place; often rectangular-though not always; white and black and/or red

Risk

Chance of injury, damage, or loss; risk is always present

Safety stop

Stop made after making a legal stop as needed to overcome a line-of-sight blockage

Separating

For situations involving multiple risks, effective timing allows you to meet each risk separately, and provides a chance to meet a moving object at a place with better space margins or visibility

Staggered stop

Stop made 15 feet before the stop line

Synergistic effect

Chemical interaction between two or more drugs, which may have an effect greater and/or different than either drug alone

Target

An object that appears in the center of the intended path-of-travel as far ahead as one can see

Target area

The area around the target

Target path

The area leading to the target

Threshold braking

Maximum braking pressure without locking the wheels or engaging the ABS

Thrust acceleration

Full engagement of the accelerator for increased acceleration, shifting more weight to the back wheels for traction, or rapid speed gain; may also initiate an automatic downshift

Total stopping distance

Made up of Perception Distance, Reaction Distance, and Braking Distance

Traction

Friction between the tire and the road

Trail braking

Slight decrease in of braking pressure, which does not change speed but allows driver to maintain control and balance when stopping or turning

Transition point

A place on the car seen in relation to the target area that is used to determine the precise moment to make a change in steering, acceleration, or braking action when exiting a turn or curve.

Uncontrolled intersection

Intersection with no signs or signals to regulate traffic, including railroad crossings that do not have flashing red lights or crossing gates

Visual control zone

The space 12 – 15 seconds ahead of your vehicle; identify risks and escape paths

Visual lead

The distance you look ahead; you should search 20-30 seconds ahead of your current position

Warning sign

Alerts drivers of specific road, environmental and traffic conditions a short distance ahead; normally diamond shaped and yellow or orange in color

Zero-tolerance

It is illegal for any driver under 21 to drive with any measurable BAC