CDL driving rules study guide
49 CFR Part 392 sets FMCSA's rules for driving commercial motor vehicles (CMVs). This guide sets out what the rule text states on ill or fatigued drivers, drugs and alcohol, schedules and speed, equipment and cargo checks before and during a trip, railroad-highway grade crossings, hazard flashers and warning devices for stopped vehicles, seat belts, fueling precautions, and texting and hand-held mobile telephones. Many duties fall on both the driver and the motor carrier; where the rule names who the duty falls on, the point says so. These are federal rules, not your State's knowledge test or manual. Every point links to the regulation and quotes its exact words.
Scope, schedules and hazardous conditions
Every motor carrier, and its officers, agents, representatives and employees who manage, maintain, operate or drive CMVs, or who hire, supervise, train, assign or dispatch drivers, must be instructed in and comply with Part 392.
“Every motor carrier, its officers, agents, representatives, and employees responsible for the management, maintenance, operation, or driving of commercial motor vehicles, or the hiring, supervising, training, assigning, or dispatching of drivers, shall be instructed in and comply with the rules in this part.”
A CMV must be operated under the laws, ordinances and regulations of the jurisdiction it is in. If an FMCSA regulation sets a higher standard of care than that local rule, the FMCSA regulation must be followed.
“Every commercial motor vehicle must be operated in accordance with the laws, ordinances, and regulations of the jurisdiction in which it is being operated. However, if a regulation of the Federal Motor Carrier Safety Administration imposes a higher standard of care than that law, ordinance or regulation, the Federal Motor Carrier Safety Administration regulation must be complied with.”
A motor carrier must not schedule a run, or permit or require a CMV trip, in a time that would make the vehicle go faster than the speed limits of the jurisdictions it travels in or through.
“No motor carrier shall schedule a run nor permit nor require the operation of any commercial motor vehicle between points in such period of time as would necessitate the commercial motor vehicle being operated at speeds greater than those prescribed by the jurisdictions in or through which the commercial motor vehicle is being operated.”
Extreme caution is required when hazardous conditions (such as snow, ice, sleet, fog, mist, rain, dust or smoke) adversely affect visibility or traction, and speed must be reduced. If conditions become sufficiently dangerous, operation must stop until the CMV can be safely operated; whenever complying with these provisions increases the hazard to passengers, the CMV may be operated to the nearest point at which their safety is assured.
“Extreme caution in the operation of a commercial motor vehicle shall be exercised when hazardous conditions, such as those caused by snow, ice, sleet, fog, mist, rain, dust, or smoke, adversely affect visibility or traction. Speed shall be reduced when such conditions exist. If conditions become sufficiently dangerous, the operation of the commercial motor vehicle shall be discontinued and shall not be resumed until the commercial motor vehicle can be safely operated. Whenever compliance with the foregoing provisions of this rule increases hazard to passengers, the commercial motor vehicle may be operated to the nearest point at which the safety of passengers is assured.”
Not covered here
Part 392 does not apply to drivers of pipeline welding trucks as defined in 49 CFR 390.38(b); that and the prohibited driving status rule in 392.15 are not detailed here. Part 392 also refers to other parts (for example the cargo securement rules in Part 393 and the definitions in 382.107); those parts are covered in their own study guides. We only write what an official source states, so study these parts with your certifying program's materials.
Ill or fatigued operator and drugs
A driver must not operate a CMV, and a motor carrier must not require or permit it, while the driver's ability or alertness is so impaired, or so likely to become impaired, through fatigue, illness or any other cause that it is unsafe to begin or continue driving.
“No driver shall operate a commercial motor vehicle, and a motor carrier shall not require or permit a driver to operate a commercial motor vehicle, while the driver's ability or alertness is so impaired, or so likely to become impaired, through fatigue, illness, or any other cause, as to make it unsafe for him/her to begin or continue to operate the commercial motor vehicle.”
Exception: in a case of grave emergency where obeying this rule would increase the hazard to occupants of the CMV or other highway users, the driver may continue to operate the CMV to the nearest place at which that hazard is removed.
“However, in a case of grave emergency where the hazard to occupants of the commercial motor vehicle or other users of the highway would be increased by compliance with this section, the driver may continue to operate the commercial motor vehicle to the nearest place at which that hazard is removed.”
A driver must not be on duty and possess, be under the influence of, or use any 21 CFR 1308.11 Schedule I substance, an amphetamine (including "pep pills" and "bennies"), a narcotic drug or its derivatives, or any other substance to a degree that makes the driver incapable of safely operating a motor vehicle.
“(a) No driver shall be on duty and possess, be under the influence of, or use, any of the following drugs or other substances: (1) Any 21 CFR 1308.11 Schedule I substance; (2) An amphetamine or any formulation thereof (including, but not limited, to “pep pills,” and “bennies”); (3) A narcotic drug or any derivative thereof; or (4) Any other substance, to a degree which renders the driver incapable of safely operating a motor vehicle.”
A motor carrier must not require or permit a driver to break these drug rules.
“No motor carrier shall require or permit a driver to violate paragraph (a) of this section.”
The amphetamine, narcotic and "any other substance" rules (paragraphs (a)(2) to (4)) do not apply to a substance given by or under the instructions of a licensed medical practitioner who has advised the driver it will not affect safe driving. This exception does not list the Schedule I paragraph (a)(1).
“Paragraphs (a) (2), (3), and (4) do not apply to the possession or use of a substance administered to a driver by or under the instructions of a licensed medical practitioner, as defined in § 382.107 of this subchapter, who has advised the driver that the substance will not affect the driver's ability to safely operate a motor vehicle.”
For this section, "possession" does not include a substance that is manifested and transported as part of a shipment.
“As used in this section, “possession” does not include possession of a substance which is manifested and transported as part of a shipment.”
Alcohol prohibition
A driver must not use alcohol, or be under its influence, within 4 hours before going on duty or operating, or having physical control of, a CMV.
“Use alcohol, as defined in § 382.107 of this subchapter, or be under the influence of alcohol, within 4 hours before going on duty or operating, or having physical control of, a commercial motor vehicle;”
While on duty, operating or in physical control of a CMV, a driver must not use alcohol, be under its influence, or have any measured alcohol concentration or detected presence of alcohol.
“Use alcohol, be under the influence of alcohol, or have any measured alcohol concentration or detected presence of alcohol, while on duty, or operating, or in physical control of a commercial motor vehicle;”
A driver must not be on duty or operate a CMV while possessing wine of at least one-half of one percent alcohol by volume, beer or distilled spirits, unless they are manifested and transported as part of a shipment, or possessed or used by bus passengers.
“Be on duty or operate a commercial motor vehicle while the driver possesses wine of not less than one-half of one per centum of alcohol by volume, beer as defined in 26 U.S.C. 5052(a), of the Internal Revenue Code of 1954, or distilled spirits as defined in section 5002(a)(8), of such Code. However, this does not apply to possession of wine, beer, or distilled spirits which are: (i) Manifested and transported as part of a shipment; or (ii) Possessed or used by bus passengers.”
A motor carrier must not require or permit a driver to violate the driver rules in 392.5(a), or to be on duty or drive if, by general appearance, conduct or other substantiating evidence, the driver appears to have used alcohol within the preceding four hours.
“No motor carrier shall require or permit a driver to— (1) Violate any provision of paragraph (a) of this section; or (2) Be on duty or operate a commercial motor vehicle if, by the driver's general appearance or conduct or by other substantiating evidence, the driver appears to have used alcohol within the preceding four hours.”
A driver found violating these rules is placed out of service immediately for 24 hours, starting when the out-of-service order is issued, and must not violate the order.
“Any driver who is found to be in violation of the provisons of paragraph (a) or (b) of this section shall be placed out-of-service immediately for a period of 24 hours. (1) The 24-hour out-of-service period will commence upon issuance of an out-of-service order. (2) No driver shall violate the terms of an out-of-service order issued under this section.”
A driver who gets such an order must report it to the employer within 24 hours, and to the State official designated by the State that issued the driver's license within 30 days. If the driver requests a review, the State report is due within 30 days of an affirmation of the order.
“(1) Report such issuance to his/her employer within 24 hours; and (2) Report such issuance to a State official, designated by the State which issued his/her driver's license, within 30 days unless the driver chooses to request a review of the order. In this case, the driver shall report the order to the State official within 30 days of an affirmation of the order by either the Division Administrator or State Director for the geographical area or the Administrator.”
A driver may petition for review by submitting a written petition within 10 days of the order's issuance to the Division Administrator or State Director for the area where it was issued.
“Any driver who is subject to an out-of-service order under this section may petition for review of that order by submitting a petition for review in writing within 10 days of the issuance of the order to the Division Administrator or State Director for the geographical area in which the order was issued.”
Not covered here
Section 392.5 itself does not set a 0.04 level: it bars any measured alcohol concentration or detected presence of alcohol while on duty. The alcohol concentration levels used in drug and alcohol testing (such as 0.04 and 0.02) are in Part 382, covered in its own study guide. We only write what an official source states, so study these parts with your certifying program's materials.
Equipment and cargo inspection
A CMV must not be driven unless the driver is satisfied that these parts are in good working order, and the driver must use them when and as needed: service brakes (including trailer brake connections), parking (hand) brake, steering mechanism, lighting devices and reflectors, tires, horn, windshield wiper or wipers, rear-vision mirror or mirrors, coupling devices, wheels and rims, and emergency equipment.
“No commercial motor vehicle shall be driven unless the driver is satisfied that the following parts and accessories are in good working order, nor shall any driver fail to use or make use of such parts and accessories when and as needed: Service brakes, including trailer brake connections. Parking (hand) brake. Steering mechanism. Lighting devices and reflectors. Tires. Horn. Windshield wiper or wipers. Rear-vision mirror or mirrors. Coupling devices. Wheels and rims. Emergency equipment.”
Drivers preparing to transport intermodal equipment must inspect the components listed in 392.7(b) and be satisfied they work before going over the road. A driver who operates the equipment over the road is deemed to have confirmed those components were in good working order when accepting it.
“Drivers preparing to transport intermodal equipment must make an inspection of the following components, and must be satisfied they are in good working order before the equipment is operated over the road. Drivers who operate the equipment over the road shall be deemed to have confirmed the following components were in good working order when the driver accepted the equipment:”
A CMV must not be driven unless the driver is satisfied that the emergency equipment required by 49 CFR 393.95 is in place and ready for use, and the driver must use it when and as needed.
“No commercial motor vehicle shall be driven unless the driver thereof is satisfied that the emergency equipment required by § 393.95 of this subchapter is in place and ready for use; nor shall any driver fail to use or make use of such equipment when and as needed.”
Except as provided in 392.9(b)(4), the driver of a truck or truck tractor must make sure the 392.9(a) cargo and equipment conditions are met before driving, and must inspect the cargo and its securement devices within the first 50 miles after beginning a trip and make any needed adjustments, including adding more securement devices.
“Except as provided in paragraph (b)(4) of this section, the driver of a truck or truck tractor must— (1) Assure himself/herself that the provisions of paragraph (a) of this section have been complied with before he/she drives that commercial motor vehicle; (2) Inspect the cargo and the devices used to secure the cargo within the first 50 miles after beginning a trip and cause any adjustments to be made to the cargo or load securement devices as necessary, including adding more securement devices, to ensure that cargo cannot shift on or within, or fall from the commercial motor vehicle;”
49 CFR 392.9, Inspection of cargo, cargo securement devices and systems
During transportation, the cargo and securement devices must be reexamined, and adjusted as needed, whenever the driver changes duty status, or the CMV has been driven for 3 hours, or for 150 miles, whichever occurs first.
“Reexamine the commercial motor vehicle's cargo and its load securement devices during the course of transportation and make any necessary adjustment to the cargo or load securement devices, including adding more securement devices, to ensure that cargo cannot shift on or within, or fall from, the commercial motor vehicle. Reexamination and any necessary adjustments must be made whenever— (i) The driver makes a change of his/her duty status; or (ii) The commercial motor vehicle has been driven for 3 hours; or (iii) The commercial motor vehicle has been driven for 150 miles, whichever occurs first.”
49 CFR 392.9, Inspection of cargo, cargo securement devices and systems
These truck and truck tractor inspection rules do not apply to the driver of a sealed CMV who has been ordered not to open it, or of a CMV loaded in a way that makes inspecting its cargo impracticable.
“The rules in this paragraph (b) do not apply to the driver of a sealed commercial motor vehicle who has been ordered not to open it to inspect its cargo or to the driver of a commercial motor vehicle that has been loaded in a manner that makes inspection of its cargo impracticable.”
49 CFR 392.9, Inspection of cargo, cargo securement devices and systems
A CMV must not be driven when any lamp or reflective device/material required by Part 393, Subpart B is obscured by the tailboard, the load or its covering, dirt, or added equipment. The exception: conspicuity treatments on the trailer's front end protection devices may be obscured by part of the load.
“No commercial motor vehicle shall be driven when any of the lamps or reflective devices/material required by subpart B of part 393 of this title are obscured by the tailboard, or by any part of the load or its covering, by dirt, or other added vehicle or work equipment or otherwise. (b) Exception. The conspicuity treatments on the front end protection devices of the trailer may be obscured by part of the load being transported.”
49 CFR 392.33, Obscured lamps or reflective devices/material
Not covered here
The cargo securement standards that 392.9 points to (49 CFR 393.100 to 393.136) are covered in the cargo securement study guide. We only write what an official source states, so study these parts with your certifying program's materials.
Railroad-highway grade crossings
Except as provided in 392.10(b), the driver of a CMV listed in 392.10(a)(1) to (6) must not cross railroad tracks at grade unless the driver first stops within 50 feet of, and not closer than 15 feet to, the tracks, then listens and looks in each direction along the tracks for an approaching train, and makes sure no train is approaching.
“Except as provided in paragraph (b) of this section, the driver of a commercial motor vehicle specified in paragraphs (a) (1) through (6) of this section shall not cross a railroad track or tracks at grade unless he/ she first: Stops the commercial motor vehicle within 50 feet of, and not closer than 15 feet to, the tracks; thereafter listens and looks in each direction along the tracks for an approaching train; and ascertains that no train is approaching.”
When it is safe, the driver may cross in a gear that lets the CMV complete the crossing without a change of gears, and must not shift gears while crossing the tracks.
“When it is safe to do so, the driver may drive the commercial motor vehicle across the tracks in a gear that permits the commercial motor vehicle to complete the crossing without a change of gears. The driver must not shift gears while crossing the tracks.”
The stop rule covers every bus transporting passengers and every CMV transporting any quantity of Division 2.3 chlorine.
“(1) Every bus transporting passengers, (2) Every commercial motor vehicle transporting any quantity of a Division 2.3 chlorine.”
It also covers every CMV required by DOT rules to be marked or placarded with one of the classifications listed in 392.10(a)(3), which include Division 1.1, Division 1.2 or 1.3, Division 2.3 Poison gas, Division 4.3, Class 7 and Class 3 Flammable, among others.
“(3) Every commercial motor vehicle which, in accordance with the regulations of the Department of Transportation, is required to be marked or placarded with one of the following classifications: (i) Division 1.1 (ii) Division 1.2, or Division 1.3 (iii) Division 2.3 Poison gas (iv) Division 4.3 (v) Class 7 (vi) Class 3 Flammable”
It also covers every cargo tank motor vehicle, loaded or empty, used to transport any hazardous material; every cargo tank motor vehicle carrying a commodity that is above its flashpoint at loading; and every cargo tank motor vehicle, loaded or empty, carrying a commodity under an exemption under Part 107, Subpart B.
“(4) Every cargo tank motor vehicle, whether loaded or empty, used for the transportation of any hazardous material as defined in the Hazardous Materials Regulations of the Department of Transportation, parts 107 through 180 of this title. (5) Every cargo tank motor vehicle transporting a commodity which at the time of loading has a temperature above its flashpoint as determined by § 173.120 of this title. (6) Every cargo tank motor vehicle, whether loaded or empty, transporting any commodity under exemption in accordance with the provisions of subpart B of part 107 of this title.”
A stop is not needed at a streetcar crossing, or railroad tracks used exclusively for industrial switching, within a business district; when a police officer or crossing flagman directs traffic to proceed; at a functioning highway traffic signal showing green that, under local law, permits crossing without slowing or stopping; at an abandoned crossing marked with a sign; or at an industrial or spur line crossing marked "Exempt" (erected only by or with the consent of the State or local authority).
“(b) A stop need not be made at: (1) A streetcar crossing, or railroad tracks used exclusively for industrial switching purposes, within a business district, as defined in § 390.5 of this chapter. (2) A railroad grade crossing when a police officer or crossing flagman directs traffic to proceed. (3) A railroad grade crossing controlled by a functioning highway traffic signal transmitting a green indication which, under local law, permits the commercial motor vehicle to proceed across the railroad tracks without slowing or stopping. (4) An abandoned railroad grade crossing which is marked with a sign indicating that the rail line is abandoned. (5) An industrial or spur line railroad grade crossing marked with a sign reading “Exempt.” Such “Exempt” signs shall be erected only by or with the consent of the appropriate State or local authority.”
Every other CMV must approach a railroad grade crossing at a speed that lets it stop before reaching the nearest rail, and must not go onto or over the crossing until due caution shows the course is clear.
“Every commercial motor vehicle other than those listed in § 392.10 shall, upon approaching a railroad grade crossing, be driven at a rate of speed which will permit said commercial motor vehicle to be stopped before reaching the nearest rail of such crossing and shall not be driven upon or over such crossing until due caution has been taken to ascertain that the course is clear.”
49 CFR 392.11, Railroad grade crossings; slowing down required
No CMV driver may drive onto a highway-rail grade crossing without enough space to drive completely through it without stopping.
“No driver of a commercial motor vehicle shall drive onto a highway-rail grade crossing without having sufficient space to drive completely through the crossing without stopping.”
Not covered here
The full list of 18 placard classifications in 392.10(a)(3) is not reproduced here; read it in the regulation. We only write what an official source states, so study these parts with your certifying program's materials.
Stopped vehicles and warning devices
When a CMV is stopped on the traveled portion or the shoulder of a highway for any cause other than necessary traffic stops, the driver must immediately turn on the hazard warning flashers and keep them flashing until the warning devices are placed. The flashers must also be used while the devices are picked up before moving.
“Whenever a commercial motor vehicle is stopped upon the traveled portion of a highway or the shoulder of a highway for any cause other than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places the warning devices required by paragraph (b) of this section. The flashing signals shall be used during the time the warning devices are picked up for storage before movement of the commercial motor vehicle.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
The flashers may be used at other times while stopped, in addition to the warning devices but not in place of them.
“The flashing lights may be used at other times while a commercial motor vehicle is stopped in addition to, but not in lieu of, the warning devices required by paragraph (b) of this section.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
Under the general rule (except as provided in the special rules of 392.22(b)(2)), whenever a CMV is stopped on the traveled portion or the shoulder of a highway for any cause other than necessary traffic stops, the driver must place the warning devices required by 393.95 as soon as possible, but in any event within 10 minutes.
“Except as provided in paragraph (b)(2) of this section, whenever a commercial motor vehicle is stopped upon the traveled portion or the shoulder of a highway for any cause other than necessary traffic stops, the driver shall, as soon as possible, but in any event within 10 minutes, place the warning devices required by § 393.95 of this subchapter”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
General placement: one device on the traffic side, 4 paces (approximately 3 meters or 10 feet) from the CMV toward approaching traffic; one at 40 paces (approximately 30 meters or 100 feet) in the center of the lane or shoulder the CMV occupies, toward approaching traffic; and one at 40 paces in the center of that lane or shoulder, away from approaching traffic.
“One on the traffic side of and 4 paces (approximately 3 meters or 10 feet) from the stopped commercial motor vehicle in the direction of approaching traffic; (ii) One at 40 paces (approximately 30 meters or 100 feet) from the stopped commercial motor vehicle in the center of the traffic lane or shoulder occupied by the commercial motor vehicle and in the direction of approaching traffic; and (iii) One at 40 paces (approximately 30 meters or 100 feet) from the stopped commercial motor vehicle in the center of the traffic lane or shoulder occupied by the commercial motor vehicle and in the direction away from approaching traffic.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
The driver of a CMV equipped with only fusees must place a lighted fusee at each of the general-rule locations, and there must be at least one lighted fusee at each location for as long as the CMV is stopped; the driver must extinguish and remove each fusee before moving.
“The driver of a commercial motor vehicle equipped with only fusees shall place a lighted fusee at each of the locations specified in paragraph (b)(1) of this section. There shall be at least one lighted fusee at each of the prescribed locations, as long as the commercial motor vehicle is stopped. Before the stopped commercial motor vehicle is moved, the driver shall extinguish and remove each fusee.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
Except as provided for business or residential districts, during the period lighted lamps are not required, three bidirectional reflective triangles or three lighted fusees must be placed as in the general rule within 10 minutes.
“Except as provided in paragraph (b)(2)(iii) of this section, during the period lighted lamps are not required, three bidirectional reflective triangles or three lighted fusees shall be placed as specified in paragraph (b)(1) of this section within a time of 10 minutes.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
Within the business or residential district of a municipality, warning devices are not required, except during the time lighted lamps are required and when street or highway lighting is not enough to make the CMV clearly discernible at 500 feet.
“The placement of warning devices is not required within the business or residential district of a municipality, except during the time lighted lamps are required and when street or highway lighting is insufficient to make a commercial motor vehicle clearly discernable at a distance of 500 feet to persons on the highway.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
If the CMV is stopped within 500 feet of a curve, crest of a hill or other obstruction to view, the driver must place the warning signal in the direction of the obstruction 100 feet to 500 feet from the CMV.
“If a commercial motor vehicle is stopped within 500 feet of a curve, crest of a hill, or other obstruction to view, the driver shall place the warning signal required by paragraph (b)(1) of this section in the direction of the obstruction to view a distance of 100 feet to 500 feet from the stopped commercial motor vehicle so as to afford ample warning to other users of the highway.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
If a CMV is stopped on the traveled portion or shoulder of a divided or one-way highway, the driver must place one warning device at 200 feet and one at 100 feet toward approaching traffic in the center of the lane or shoulder the CMV occupies, plus one at the traffic side within 10 feet of the rear of the CMV.
“If a commercial motor vehicle is stopped upon the traveled portion or the shoulder of a divided or one-way highway, the driver shall place the warning devices required by paragraph (b)(1) of this section, one warning device at a distance of 200 feet and one warning device at a distance of 100 feet in a direction toward approaching traffic in the center of the lane or shoulder occupied by the commercial motor vehicle. He/she shall place one warning device at the traffic side of the commercial motor vehicle within 10 feet of the rear of the commercial motor vehicle.”
49 CFR 392.22, Emergency signals; stopped commercial motor vehicles
No driver may attach, or permit anyone to attach, a lighted fusee or other flame-producing emergency signal to any part of a CMV.
“No driver shall attach or permit any person to attach a lighted fusee or other flame-producing emergency signal to any part of a commercial motor vehicle.”
Flame-producing emergency signals must not be used for a CMV carrying Division 1.1, 1.2 or 1.3 explosives, a cargo tank motor vehicle used for Class 3 or Division 2.1 (loaded or empty), or a CMV using compressed gas as a motor fuel. Reflective triangles, red electric lanterns or red emergency reflectors are used instead, placed as in 392.22(b).
“No driver shall use or permit the use of any flame-producing emergency signal for protecting any commercial motor vehicle transporting Division 1.1, Division 1.2, or Division 1.3 explosives; any cargo tank motor vehicle used for the transportation of any Class 3 or Division 2.1, whether loaded or empty; or any commercial motor vehicle using compressed gas as a motor fuel. In lieu thereof, emergency reflective triangles, red electric lanterns, or red emergency reflectors shall be used, the placement of which shall be in the same manner as prescribed in § 392.22(b).”
Not covered here
The rule on leaking flammable liquid or gas (392.22(b)(2)(vi)) is not summarized here. Sections 392.20 and 392.21 are reserved in the current text. The required warning equipment itself is listed in 49 CFR 393.95. We only write what an official source states, so study these parts with your certifying program's materials.
Seat belts, fueling and other practices
A driver must not operate a CMV that has a seat belt assembly at the driver's seat unless properly restrained by it, and a motor carrier must not require or permit it.
“No driver shall operate a commercial motor vehicle, and a motor carrier shall not require or permit a driver to operate a commercial motor vehicle, that has a seat belt assembly installed at the driver's seat unless the driver is properly restrained by the seat belt assembly.”
In a property-carrying CMV that has seat belt assemblies at the seats for other occupants, the driver must not operate it (and the carrier must not require or permit it) unless all other occupants are properly restrained.
“No driver shall operate a property-carrying commercial motor vehicle, and a motor carrier shall not require or permit a driver to operate a property-carrying commercial motor vehicle, that has seat belt assemblies installed at the seats for other occupants of the vehicle unless all other occupants are properly restrained by such seat belt assemblies.”
No driver or any employee of a motor carrier may: fuel a CMV with the engine running, except when running the engine is necessary to fuel it; smoke or expose any open flame near a CMV being fueled; fuel a CMV unless the fuel hose nozzle is continuously in contact with the intake pipe of the fuel tank; or permit, insofar as practicable, any other person to do things likely to cause fire or explosion.
“No driver or any employee of a motor carrier shall: (a) Fuel a commercial motor vehicle with the engine running, except when it is necessary to run the engine to fuel the commercial motor vehicle; (b) Smoke or expose any open flame in the vicinity of a commercial motor vehicle being fueled; (c) Fuel a commercial motor vehicle unless the nozzle of the fuel hose is continuously in contact with the intake pipe of the fuel tank; (d) Permit, insofar as practicable, any other person to engage in such activities as would be likely to result in fire or explosion.”
Unless specifically authorized in writing by the motor carrier, no driver may transport any person, or permit any person to be transported, on a CMV other than a bus. The authorization must state the person's name, where the transportation begins and ends, and the date it expires. No written authorization is needed for employees or other persons the motor carrier assigns to the CMV, anyone transported while aid is given in an accident or other emergency, or an attendant caring for livestock.
“Unless specifically authorized in writing to do so by the motor carrier under whose authority the commercial motor vehicle is being operated, no driver shall transport any person or permit any person to be transported on any commercial motor vehicle other than a bus. When such authorization is issued, it shall state the name of the person to be transported, the points where the transportation is to begin and end, and the date upon which such authority expires. No written authorization, however, shall be necessary for the transportation of: (1) Employees or other persons assigned to a commercial motor vehicle by a motor carrier; (2) Any person transported when aid is being rendered in case of an accident or other emergency; (3) An attendant delegated to care for livestock.”
No driver may use a radar detector in a CMV or operate a CMV that is equipped with or contains one, and no motor carrier may require or permit it.
“(a) No driver shall use a radar detector in a commercial motor vehicle, or operate a commercial motor vehicle that is equipped with or contains any radar detector. (b) No motor carrier shall require or permit a driver to violate paragraph (a) of this section.”
Not covered here
Not covered here: the reserve fuel and materials of trade limits in 392.51, the bus rules in 392.62 and 392.63, closed-body exits in 392.64, the carbon monoxide rule in 392.66, open flame heaters in 392.67, and the 392.60(b) exclusion for farmers' vehicles carrying agricultural commodities or farm supplies. We only write what an official source states, so study these parts with your certifying program's materials.
Texting and hand-held mobile telephones
No driver may engage in texting while driving, and no motor carrier may allow or require its drivers to.
“(a) Prohibition. No driver shall engage in texting while driving. (b) Motor carriers. No motor carrier shall allow or require its drivers to engage in texting while driving.”
For the texting rule only, driving means operating a CMV with the motor running, including while temporarily stationary because of traffic, a traffic control device or other momentary delays. It does not include operating a CMV, with or without the motor running, after the driver has moved it to the side of, or off, a highway and halted where it can safely remain stationary.
“For the purpose of this section only, driving means operating a commercial motor vehicle, with the motor running, including while temporarily stationary because of traffic, a traffic control device, or other momentary delays. Driving does not include operating a commercial motor vehicle with or without the motor running when the driver moved the vehicle to the side of, or off, a highway, as defined in 49 CFR 390.5, and halted in a location where the vehicle can safely remain stationary.”
Texting while driving is permitted when necessary to communicate with law enforcement officials or other emergency services.
“Texting while driving is permissible by drivers of a commercial motor vehicle when necessary to communicate with law enforcement officials or other emergency services.”
No driver may use a hand-held mobile telephone while driving a CMV, and no motor carrier may allow or require its drivers to.
“(1) No driver shall use a hand-held mobile telephone while driving a CMV. (2) No motor carrier shall allow or require its drivers to use a hand-held mobile telephone while driving a CMV.”
For the hand-held phone rule only, driving means operating a CMV on a highway, including while temporarily stationary because of traffic, a traffic control device or other momentary delays. It does not include operating a CMV after moving it to the side of, or off, a highway and halting where it can safely remain stationary.
“For the purpose of this section only, driving means operating a commercial motor vehicle on a highway, including while temporarily stationary because of traffic, a traffic control device, or other momentary delays. Driving does not include operating a commercial motor vehicle when the driver has moved the vehicle to the side of, or off, a highway and has halted in a location where the vehicle can safely remain stationary.”
Using a hand-held mobile telephone is permitted when necessary to communicate with law enforcement officials or other emergency services.
“Using a hand-held mobile telephone is permissible by drivers of a CMV when necessary to communicate with law enforcement officials or other emergency services.”
Not covered here
Part 392 does not define "texting", "mobile telephone" or "use a hand-held mobile telephone"; those definitions are elsewhere in the FMCSA rules and are not quoted here. We only write what an official source states, so study these parts with your certifying program's materials.
Sources
- eCFR: 49 CFR 392.1, Scope of the rules in this part (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.2, Applicable operating rules (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.6, Schedules to conform with speed limits (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.14, Hazardous conditions; extreme caution (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.3, Ill or fatigued operator (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.4, Drugs and other substances (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.5, Alcohol prohibition (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.7, Equipment, inspection and use (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.8, Emergency equipment, inspection and use (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.9, Inspection of cargo, cargo securement devices and systems (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.33, Obscured lamps or reflective devices/material (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.10, Railroad grade crossings; stopping required (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.11, Railroad grade crossings; slowing down required (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.12, Highway-rail crossings; safe clearance (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.22, Emergency signals; stopped commercial motor vehicles (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.24, Emergency signals; flame-producing (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.25, Flame producing devices (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.16, Use of seat belts (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.50, Ignition of fuel; prevention (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.60, Unauthorized persons not to be transported (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.71, Radar detectors; use and/or possession (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.80, Prohibition against texting (as of Nov 3, 2026)Checked November 6, 2026
- eCFR: 49 CFR 392.82, Using a hand-held mobile telephone (as of Nov 3, 2026)Checked November 6, 2026
Other CDL study guides: License standards, Driver qualifications, Hours of service, Inspection and maintenance, Brakes, Cargo securement, Drug and alcohol testing, Hazmat classes and definitions, Hazmat shipping papers and emergency information, Hazmat marking, Hazmat placarding, Hazmat highway carriage, loading and segregation, Hazmat driving, parking and training