Colorado Hazmat CDL Practice Test

This is a free 20-question practice test for the Hazmat portion of the Colorado Commercial Driver's License knowledge exam. Questions are pulled from a pool of 68 drawn from the AAMVA CDL Manual, which is the source document the Colorado Division of Motor Vehicles uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Colorado.

Question 1 of 20

Hazardous materials are products that:

Are heavier than normal cargo
Pose a risk to health, safety, or property during transportation
Can only be hauled at night
Require a special trailer color

Correct. Hazardous materials (hazmat) are products that pose a risk to health, safety, or property during transportation. Hazmat regulations are codified in 49 CFR.

Question 2 of 20

A driver may not carry hazmat aboard a vehicle without:

A current Hazmat (H) endorsement on the CDL
A green light
Two cell phones
A reflective vest

Correct. Hauling placardable hazmat requires the H endorsement, which includes a TSA Threat Assessment background check.

Question 3 of 20

How many hazard classes are there?

Three
Five
Nine
Twelve

Correct. There are nine hazard classes: 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers and organic peroxides, 6 toxic and infectious, 7 radioactive, 8 corrosive, 9 miscellaneous.

Question 4 of 20

The Hazardous Materials Table (HMT) lists:

Only flammable liquids
Each hazardous material with its proper shipping name, hazard class, ID number, packing group, and required label
Only items shipped by air
Only items shipped by truck

Correct. The HMT in 49 CFR §172.101 lists every hazardous material with its proper shipping name, hazard class, identification number, packing group, label requirements, and special provisions.

Question 5 of 20

A hazmat driver must complete which special training?

General awareness, function-specific, safety, security awareness, and in-depth security if a security plan is required
Forklift training
Basic first aid only
Defensive driving only

Correct. PHMSA requires general awareness, function-specific, safety, security awareness, and in-depth security training (when a security plan applies). Carriers document and re-train every three years.

Question 6 of 20

Hazard Class 1 is:

Flammable liquids
Explosives
Corrosives
Radioactive materials

Correct. Class 1 covers explosives, divided into divisions 1.1 through 1.6 by mass-explosion and projection hazard.

Question 7 of 20

Class 1.1, 1.2, or 1.3 explosives must be parked:

Anywhere
In an attended location with a qualified person within 100 feet, awake and able to see the vehicle
At a school
At a gas station

Correct. Division 1.1, 1.2, and 1.3 explosives, and Division 2.3 or 6.1 PIH cargo, must have an attended-vehicle (qualified person within 100 feet, awake, able to see the vehicle).

Question 8 of 20

A vehicle that has been transporting hazmat may need to be:

Decontaminated and re-placarded as required after unloading
Painted
Sold
Inspected by USCG

Correct. After unloading, the vehicle may need decontamination depending on the cargo. Placards may need to be removed unless residue still requires them.

Question 9 of 20

Bulk packaging of certain corrosives requires:

No special markings
Display of the proper shipping name on each side and the four-digit ID number on each side and end
Only one placard
Painted red

Correct. Bulk packaging of corrosives, like other hazmat, requires shipping name on the sides and ID-number marking on each side and end.

Question 10 of 20

The shipping paper for hazmat must include:

Only the destination
Proper shipping name, hazard class, ID number with UN/NA prefix, packing group, total quantity, and emergency contact
Only the weight
Only the carrier name

Correct. A complete shipping paper includes proper shipping name, hazard class or division, UN/NA ID number, packing group (where applicable), total quantity and unit, and a 24-hour emergency contact.

Question 11 of 20

When transporting hazmat, you must check the cargo every:

Mile
100 miles
150 miles or 3 hours, plus changes of duty status
500 miles

Correct. Federal cargo securement: check at the start, then every 150 miles or 3 hours of driving, plus every change of duty status.

Question 12 of 20

A driver is required to carry an ERG (or equivalent) when:

Driving any commercial vehicle
Transporting any quantity of hazardous materials
Only when hauling explosives
Only on weekends

Correct. Whenever hazmat is being transported, the driver must have access to current ERG information for the materials in question.

Question 13 of 20

A "DANGEROUS" placard may be used:

Instead of multiple Table 2 placards when 1,001+ lbs of two or more Table 2 materials are loaded
For any cargo
For non-hazmat
For hazmat below 100 lbs

Correct. When more than two Table 2 materials are aboard with combined weight over 1,001 lbs (none over 2,205 lbs at one stop), a single DANGEROUS placard may substitute.

Question 14 of 20

A leaking package of hazmat:

Should be immediately driven to the destination
Must not be transported; secure and report
Should be wrapped in plastic
Should be ignored

Correct. Never transport a leaking package. Secure the area, report to the carrier, contact emergency services if the leak poses immediate danger.

Question 15 of 20

Placards must be displayed on:

One side
Two sides
Three sides
All four sides of the vehicle

Correct. Placards are displayed on all four sides of the vehicle — front, back, and both sides.

Question 16 of 20

Placards must be at least how many inches on each side?

10.75 inches (273 mm)
5 inches
15 inches
20 inches

Correct. Placards are diamond-shaped, at least 250 mm (about 10.75 inches) on each side.

Question 17 of 20

A driver of a hazmat-loaded vehicle must check the tires:

Once before the trip
At the start of the trip and every time the vehicle is parked
Only at fueling
Never

Correct. Hazmat drivers must check tires at the beginning and again each time the vehicle is parked. A flat or smoking tire must be addressed before continuing.

Question 18 of 20

Electrical equipment in cargo areas of vehicles transporting Class 3 (flammable) liquids must be:

Disconnected
Spark-free or explosion-proof to prevent ignition
Painted red
Made of plastic

Correct. Wiring and electrical fittings in flammable-liquid loading areas must be designed to prevent ignition — spark-free, sealed, or explosion-proof.

Question 19 of 20

When loading or unloading cargo tanks of flammable liquid, the driver must:

Stay alert and within 25 feet of the vehicle, with a clear view
Leave the area
Smoke
Run the engine at high RPM

Correct. During cargo-tank flammable-liquid loading or unloading, the driver must remain attentive and within 25 feet of the vehicle with an unobstructed view.

Question 20 of 20

You must notify your dispatcher and the carrier whenever:

You receive any traffic ticket
Any hazmat incident occurs
Anytime you stop
Anytime you fuel

Correct. Hazmat incidents — spillage, fire, contamination, injury, evacuation, or property damage — require immediate carrier notification.

About the Colorado Hazmat exam

Most states administer 30 Hazmat questions and require 80% to pass. The exam covers hazard classes, the shipping paper, placards and labels, loading and unloading, driving and parking rules, emergency response, and the Emergency Response Guidebook (ERG).

The Colorado Division of Motor Vehicles follows the federal CDL standards established by FMCSA. To earn the Hazmat credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full Hazmat question bank or browse all Colorado CDL practice tests.