Chapter 10: Commercial/ Heavy Vehicle Stabilization Operations

Question 1

Many commercial vehicles equip each axle with ____; rescuers can use these locations for stabilization. In addition, some commercial vehicles have specially designed ____ that can also be used as contact points for cribbing or jacks.

Answer 1

• a piece of tubing welded on the axle near each wheel

* jack plates and engine supports

Question 2

Jacks should be equipped with ____ that allow rescuers to operate them from the outside perimeter of the vehicle.

Answer 2

handles

Question 3

Rescuers must ____ they need to stabilize before beginning stabilization operations.

Answer 3

• calculate the load

Question 4

How can rescuers estimate the weight of the commercial/ heavy vehicles involved in the extrication?.

Answer 4

• 20,000 pounds for each drive axle
• Thin or slim profile tires on a steering axle = 10,000 pounds
• balloon wide profile tires on a steering axle = 25,000 pounds

Question 5

The majority of trucks involved in collisions will be found ____

Answer 5

wheel-resting

Question 6

What makes a trucks center of gravity significantly higher than that of other vehicles?

Answer 6

The distance between the road surface and the bottom of the chassis is significantly greater.

Question 7

On cab over units, rescuers should secure the cab with ____ to prevent it from tilting forward unexpectedly during extrication operations.

Answer 7

• rope, webbing, or chains

Question 8

On truck cabs mounted on air suspension systems rescuers should ____ as part of stabilization.

Answer 8

marry the cab to the chassis to minimize movement from the air suspension system

Question 9

To marry the cab to the frame on a truck with an air suspension system rescuers should ____

Answer 9

• fill the voids on the cab with cribbing and secure the cab to the frame with a tensioning device.

Question 10

To stabilize a trailer attached to the truck requiring extrication operations, rescuers should ____

Answer 10

• chock the wheels of the trailer, confirm the kingpin is locked, and lower the landing gear.

Question 11

Kingpin

Answer 11

Attaching pin on a semitrailer that connects with pivots within the lower coupler of a truck tractor or converter dolly while coupling the two units together.

Question 12

In tractor trailer accidents rescuers should consider ____ as an added means of vehicle stabilization.

Answer 12

applying the air brake system

Question 13

A major portion of applying the air brake system as an added means of stabilization in a tractor trailer incident is ____. Rescuers can ____ to disconnect the air system.

Answer 13

• disconnecting the air system from the tractor trailer.

* disconnect the glad hand connection

Question 14

After the air system has been disengaged during a tractor trailer incident, the trailer brakes will ____

Answer 14

lock with the spring brake mechanism when the pressure falls below 20 - 40 psi.

Question 15

Rescuers should only disconnect glad hands after ____

Answer 15

completing initial stabilization

Question 16

To disconnect glad hand connections rescuers should ____

Answer 16

turn the connection approximately 90 degrees and pull the connections apart.

Question 17

A medium or heavy truck on its side can sometimes ____ to stabilize than other smaller vehicles because ____.

Answer 17

• be easier

* the weight and shape of these trucks often make them relatively stable when they come to rest.

Question 18

To stabilize a side-resting truck, rescuers should ____. Rescuers may need to ____ because of the roundness of the cab’s roof edge.

Answer 18

• install cribbing or other supports at the cab’s door posts.
• invert step chocks before sliding them under the vehicle

Question 19

When deciding how to stabilize a truck that rests in an unusual position, rescue personnel should ____

Answer 19

consider the vehicles center of gravity, mass, cargo, as well as the capabilities of their equipment.

Question 20

If a vehicle is wedged under another vehicle or object, rescuers should ____

Answer 20

attempt to limit if not eliminate the vehicles reaction when they remove the overlying object.

Question 21

If a truck stops on a steep slope or hangs over the edge of a bridge or cliff, rescuers can ____

Answer 21

use cribbing and/or rigging to offset the forces of gravity and secure the vehicle in place.

Question 22

Bombproof Anchor Point

Answer 22

(1) Slang reference to an anchor that is absolutely immovable, such as a huge boulder, a large tree, or a fire engine.
(2) Any anchor point capable of withstanding forces in excess of those that might be generated by the rescue operation or even catastrophic failure (and resultant shock load) of a raising or lowering system.

Question 23

When chocking wheels of a bus, rescuers should use ____

Answer 23

wheel chocks and not pieces of cribbing.

Question 24

Rescuers should only consider an anchor point bomb proof if ____

Answer 24

the weight of any object attached to that anchor absolutely will not move the anchor point.

Question 25

Unless rescuers are positive that a bus has a mechanical suspension system, they should ____

Answer 25

treat the bus as if it has an air suspension system.

Question 26

Because most transit and commercial buses do not have a rigid frame, they have specially designed ____ for use as contact points for cribbing or jacks.

Answer 26

jack plates

Question 27

On transit buses jack plates are located ____

Answer 27

slightly behind each axle, near each wheel.

Question 28

On commercial buses jack plate are located ____

Answer 28

under the body between the two rear axles and in back of the front axle.

Question 29

Rescuers should support ____ jack plates on a bus to completely stabilize the vehicle.

Answer 29

all four

Question 30

If hydraulic jacks are used to lift a bus, jacks of at least ____ capacity should be used.

Answer 30

8 ton

Question 31

Side resting and roof resting vehicles are especially susceptible ____, making ____ a high priority.

Answer 31

• Leaking flammable fluids

* fire protection