Driver's Education: Vehicle Dynamics, Restraints, and Stopping Distances

Vocabulary practice flashcards covering vehicle physics, physical roadway forces, restraint systems, reaction times, and stopping distances based on driver education materials.

Gravity

The force that pulls vehicles toward the earth.

Friction

The gripping action that keeps tires from slipping.

Passive restraint device

A restraint device, such as an air bag, that works automatically and that the vehicle occupant does not need to fasten.

Active restraint device

A safety belt that a vehicle's occupant must manually adjust.

Traction

The friction that allows tires to grip the roadway surface.

Tread

The grooved surface of a tire that grips the roadway.

Banked curve

A roadway curve that is engineered higher on the outside edge than on the inside.

Force of impact

The force with which one moving object strikes another object.

Blowout

A sudden loss of tire air pressure that can be caused by driving on a bald tire.

Energy of motion

The kinetic energy an object possesses when it moves, acting as one of the two main forces on a vehicle in a curve along with traction.

Center of gravity

The point around which an object's total weight is evenly balanced and distributed.

Restraint device

Any part or mechanism of a vehicle designed to hold an occupant securely during a collision.

Perception time

The length of time required for a driver to identify, predict, and decide to slow down for a roadway hazard.

Perception distance

The distance a vehicle travels while the driver is identifying a roadway situation.

Reaction time

The length of time a driver takes to execute an action in response to a hazard after identifying it.

Reaction distance

The distance a vehicle travels while the driver identifies and reacts to a detected hazard.

Braking distance

The distance traveled by a vehicle while stopping.

Total stopping distance

The distance a vehicle travels from the time the driver applies the brakes until the vehicle comes to a complete stop, calculated as the sum of perception distance, reaction distance, and braking distance.

Roadway conditions for high traction

Roadway surface characteristics that must be clean, dry, level, and smooth to maintain optimal grip.

Bridges and overpasses

Specific highway structures and areas where roadway ice tends to form first.

Cold tire pressure check

The required state of tire temperature when checking tire inflation pressure to ensure an accurate reading.

Common collision threshold

The statistical range in which most traffic collisions occur: at speeds under $40\text{ mph}$ and within $25\text{ miles}$ of home.

Effect of gravity uphill

The opposing downward pull of gravity that causes a vehicle's speed to decrease when driving up an incline.

Vehicle weight and impact relationship

When traveling at identical speeds, heavier vehicles strike with greater force; doubling the weight of a vehicle causes it to strike an object twice as hard.

Speed (in collision impact)

The single most important determining factor in how hard a vehicle strikes an object during a collision.

Stopping distance at $55\text{ mph}$

A total stopping distance of $297\text{ feet}$, consisting of an $81\text{ feet}$ perception distance, a $60\text{ feet}$ reaction distance, and an approximate $156\text{ feet}$ braking distance.