Texas Hazmat CDL Practice Test

This is a free 20-question practice test for the Hazmat portion of the Texas 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 Texas Department of Public Safety Driver License Division 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 Texas.

Question 1 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 2 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 3 of 20

When loading a vehicle with hazardous materials, you should:

Set the parking brake, chock the wheels, turn off the engine
Leave the engine running
Smoke if outside the cab
Skip the brake check

Correct. Set the parking brake, chock wheels of cargo tank vehicles, and shut off the engine before loading or unloading flammables.

Question 4 of 20

You discover a leak in a Class 3 (flammable liquid) shipment. You should:

Continue driving until you find a safe place
Stop, secure the area, notify emergency services, do not transfer cargo on the road, do not move the vehicle further than necessary
Drive faster to deliver the load
Open the placards

Correct. Stop in a safe location, secure the area, call 911, and notify your dispatcher. Do not transfer cargo by the side of the road.

Question 5 of 20

Where can a hazmat-placarded vehicle never be parked?

On private property
Within 5 feet of the traveled portion of a roadway, except briefly for vehicle operation
Anywhere
At a truck stop

Correct. Never park within 5 feet of the traveled portion of a road. Avoid populated areas, near open fires, and near places where people congregate.

Question 6 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 7 of 20

When you stop at a railroad crossing in a placarded hazmat vehicle, you must stop:

On the tracks
Between 15 and 50 feet from the nearest rail
Anywhere
Only if a train is visible

Correct. Placarded hazmat vehicles must stop at every railroad crossing 15 to 50 feet from the nearest rail. Look and listen for trains.

Question 8 of 20

When in the cab with the engine running, the hazmat shipping paper must be:

In the trailer
Within the driver's reach — clipped on the driver's door clip or on the driver's seat
In the glove compartment
In the trunk

Correct. When in the seat with the engine running, keep shipping papers within reach (driver-side door clip or on the seat). When out of the vehicle, leave on the seat or in the door pouch.

Question 9 of 20

The "Wetline" rule for cargo tanks of flammable liquid:

Limits the amount of flammable liquid that may be left in product piping during transit
Allows leaks
Bans tankers
Permits unlimited residue

Correct. Wetline regulations restrict residual flammable liquid in cargo-tank product piping during transportation, due to ignition risk if a piping line is breached.

Question 10 of 20

Hazard Class 8 is:

Flammable solids
Corrosives
Radioactive
Gases

Correct. Class 8 is corrosive materials — sulfuric acid, sodium hydroxide, hydrochloric acid, etc.

Question 11 of 20

The Emergency Response Guidebook (ERG) is used to:

Plan routes
Look up the four-digit hazmat ID number to find emergency response procedures
Calculate fuel cost
Find truck stops

Correct. The ERG cross-references the four-digit ID number from the placard or shipping paper to a guide page with isolation distance, response procedures, and first aid.

Question 12 of 20

The four-digit ID number on a placard or shipping paper is the:

UN/NA identification number for the material
The driver's permit number
The truck VIN
The DOT registration number

Correct. The four-digit number is the UN/NA ID — used with the ERG to find emergency response procedures.

Question 13 of 20

Mixing certain hazmat in one shipment is prohibited because:

Of cost
They may react dangerously together; the segregation table specifies prohibitions
It is too heavy
Of regulations on cargo color

Correct. Some classes react dangerously when mixed (e.g., acids with cyanides, oxidizers with flammables). The segregation table prohibits these mixtures.

Question 14 of 20

Hazmat drivers must report any change of:

Address to the licensing agency
Daily route
Diet
Vehicle paint color

Correct. Address changes must be reported to the state licensing agency in line with state CDL requirements; some states require reporting within 30 days.

Question 15 of 20

You should never smoke or carry an open flame near hazmat that is:

Class 1 (explosives), Class 2.1 (flammable gas), Class 3 (flammable liquid), or oxidizers (Class 5.1)
Any class
Class 9
Class 6

Correct. Smoking or open flames are dangerous near explosives, flammable gases, flammable liquids, and oxidizers. The 25-foot rule applies during loading.

Question 16 of 20

A driver of a placarded hazmat vehicle approaching a tunnel that prohibits hazmat must:

Use a designated alternate route
Drive through quickly
Cover the placards
Go around the prohibition sign

Correct. Many tunnels prohibit certain placarded vehicles. Use the designated alternate route. Bypassing the prohibition is a serious violation.

Question 17 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 18 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 19 of 20

When a hazmat shipment crosses international borders:

Documentation may need to comply with both US and Canadian/Mexican regulations
No special documentation is needed
Only US regulations apply
Only foreign regulations apply

Correct. Cross-border hazmat may require documentation in compliance with both jurisdictions, plus customs paperwork.

Question 20 of 20

The Hazmat (H) endorsement requires:

Only a knowledge test
A knowledge test plus a TSA Threat Assessment background check
Just a fee
A skills test only

Correct. Hazmat applicants pass a knowledge test and complete the TSA Threat Assessment (HME), which involves fingerprints and an FBI background check.

About the Texas 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 Texas Department of Public Safety Driver License Division 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 Texas CDL practice tests.