1. VEHICLE MOVEMENT
CHAPTER 12

2. NATURAL LAWS
LAW OF INERTIA
FRICTION
GRAVITY
MOMENTUM

3. APPROPRIATE SPEED SPEED AFFECTS VISIBILITY
INCLEMENT WEATHER REDUCES TRACTION
MAKE SURE STOPPING ZONE IS LESS THAN WHAT YOU CAN SEE
MOST DRIVING ACTIONS REQUIRE 1/2 TO 3/4 OF A SECOND
SLOW DOWN TO KEEP A SAFE DISTANCE
MILEAGE IMPROVES BY 20% WHEN SPEED IS 55 INSTEAD OF 65 MPH

4. TOTAL STOPPING DISTANCE
HUMAN PERCEPTION, HUMAN REACTION, VEHICLE BRAKING
YOU TRAVEL FT AT 60 MPH DURING PERCEPTION STAGE
IT TAKES ANOTHER 1/2 TO 3/4 SEC TO REACT
VEHICLE BRAKING TIME IS USUALLY LESS THAN 1/4 SEC.
CHECK FIG ON PG. 255
IT TAKES FEET TO STOP AT 60 MPH

5. THE NATURAL LAWS
INERTIA: MOVING OBJECTS CONTINUE TO MOVE IN A STRAIGHT LINE; OBJECT AT REST STAY AT REST
FRICTION: FORCE BETWEEN TWO SURFACES, TRACTION OR ADHESION(STICKING TOGETHER). IT IS AFFECTED BY TIRE PRESSURE & CONDITION, RAIN (1/12 OF AN INCH AT 55 MPH), SNOW, & ICE, ROAD CONDITIONS.

6. MORE NATURAL LAWS MOMENTUM: COMBINATION OF WEIGHT AND SPEED
KINETIC ENERGY: ENERGY OF MOTION, CHANGES WITH WEIGHT, TAKES LONGER TO ACC. AND BRAKE
GRAVITY (CENTER OF): MORE STABLE IF LOWER

7. STEERING AND BRAKING
SPEED, VEHICLE CONDITION, AND ROADWAY CONDITIONS AFFECT BRAKING DISTANCE.
STEERING IS AFFECTED BY FRICTION AND INERTIA
DIRECTIONAL CONTROL: VEHICLE’S ABILITY TO HOLD A STRAIGHT LINE

8. STEERING AROUND A CURVE
MUST OVERCOME INERTIA
CENTRIFUGAL FORCE: BEING PULLED TOWARD OUTER PART OF A CURVE. PUSHES YOU TO DIRECTION OPPOSITE OF WAY YOU ARE TURNING.
FRICTION ACTS TO OVER COME IT

9. GRAVITY AND THE ROAD
BANKED ROADS: BUILT HIGHER ON THE OUTSIDE. HELPS OVERCOME CENT. FORCE
CROWNED ROADS: HIGHER IN CENTER,GRAVITY WILL PULL YOU RIGHT, SLOWER SPEEDS GIVE MORE CONTROL