To help ensure the safe operation of commercial motor vehicles (CMVs), the Federal Motor Carrier Safety Regulations (FMCSRs) include specific requirements related to the behavior, actions, and physical state of the driver behind the wheel. These requirements are found in 49 CFR Part 392, Driving of Motor Vehicles.

Included are driver requirements related to illness or fatigue, drug/alcohol possession or use, texting, and using hand-held cell phones. Operational requirements related to railroad crossings, speed limits, seat belts, hazardous driving conditions, stopping on the road or shoulder, defensive driving, and other prohibited practices are also discussed.

• Motor carriers and drivers of “commercial motor vehicles” (CMVs) that transport passengers or property on “highways” in “interstate commerce” must comply with federal CMV driving laws and regulations.
• Motor carriers and drivers that are only involved in intrastate (in-state) commerce are subject to that state’s driving-related laws and regulations.

CMV driving regulations apply to motor carriers and drivers who operate CMVs.

A “commercial motor vehicle” is any self-propelled or towed vehicle used on a highway to transport property or passengers in interstate commerce when the vehicle:

• Has a gross vehicle weight rating (GVWR) or gross combination weight rating (GCWR), or gross vehicle weight (GVW) or gross combination weight (GCW), of 10,001 pounds or more, whichever is greater; or
• Is designed or used to transport 9 or more passengers (including the driver) for compensation or 16 or more passengers (including the driver) not for compensation; or
• Is transporting hazardous materials of a type or quantity that requires placarding.

A “highway” is any road, street, or way (whether on public or private property) that is “open to public travel,” meaning that the road or way is available (except during scheduled periods, extreme weather, or emergency conditions) and passable by four-wheel standard passenger cars, and is open to the general public for use without restrictive gates, prohibitive signs, or regulation other than restrictions based on size, weight, or class of registration.

Intrastate operations

A key part of the CMV definition is “interstate commerce,” meaning commerce that crosses state or national borders. Motor carriers and drivers that are only involved in intrastate (in-state) commerce are subject to that state’s driving-related laws and regulations. Under those laws or regulations, the CMV definition may differ from the one described above.

Drivers are prohibited from driving, and motor carriers may not allow them to drive, when the driver’s ability or alertness is so impaired (or so likely to become impaired) that driving would be unsafe. This impairment could come from illness, fatigue, or any other cause. The only exception to this rule is when there is a “grave emergency” and continuing to drive is less hazardous to human life than not driving, in which case the driver can continue to drive to the nearest place of safety.

Note that this prohibition is not found in the Department of Transportation’s hours-of-service (HOS) rules, so even drivers who are exempt from the HOS rules are prohibited from driving while ill or fatigued.

• Commercial motor vehicle (CMV) drivers may not use or be under the influence of alcohol within four hours prior to driving, or at any time while driving.
• CMV drivers may possess or use a non-Schedule I substance only if it was administered or prescribed by a licensed medical practitioner who advised that the substance will not affect the driver’s ability to drive safely.

Drug use

While on duty, CMV drivers may never possess (except as part of a shipment), be under the influence of, or use, any of the following substances:

• Any “Schedule I” substance as listed in 21 CFR 1308.11;
• Any amphetamine or related formulation;
• Any narcotic drug or derivative; or
• Any other substance that renders the driver incapable of safely operating a motor vehicle.

EXCEPTION: Drivers may possess or use a non-Schedule I substance if it was administered to the driver by or under the instructions of a licensed medical practitioner who advised the driver that the substance will not affect the ability to drive safely. (see 392.4)

Alcohol use

CMV drivers may not:

• Use or be under the influence of alcohol within four hours of going on duty, or at any time while on duty (including having any measured alcohol concentration or detected presence of alcohol). A driver’s general appearance, conduct, or other evidence can be used to substantiate alcohol use within the prior four hours.
• Be on duty while possessing wine, beer, or distilled spirits, except when the alcohol is manifested and transported as part of a shipment or possessed by bus passengers.

NOTE: A driver found to be in violation of these rules must be immediately placed out of service for 24 hours. Any driver who is issued an out-of-service order must report the order to the employer within 24 hours and to the state that issued the driver’s license within 30 days. (392.5(d))

• Texting includes text messaging, emailing, and instant messaging.
• Texting does not include inputting, selecting, or reading information on a GPS or navigation system.
• Using at least one hand to hold a mobile phone to conduct a voice communication while driving a commercial motor vehicle (CMV) is prohibited.

Texting

Drivers may not send or read text messages while driving a CMV, including while stuck in traffic. Texting is allowed, however, when legally parked or to contact emergency services. “Texting” is defined as manually entering alphanumeric text into, or reading text from, an electronic device.

Hand-held phone use

Drivers may not use a hand-held cell phone while driving a CMV. Refer to the following chart to see the actions that are and are not allowed:

• Federal Motor Carrier Safety Administration (FMCSA) guidelines suggest that commercial motor vehicle (CMV) drivers should average no more than about 10 mph below the average posted speed limit over a 10-hour period.
• Motor carriers are prohibited from scheduling runs that are impossible for a CMV driver to complete without speeding.
• All commercial motor vehicle (CMV) drivers and passengers on property-carrying vehicles must wear seat belts.

Speeding

CMV drivers are prohibited from exceeding speed limits, and motor carriers are prohibited from allowing speeding or requiring drivers to speed by scheduling runs that are impossible to complete without speeding.

FMCSA guidelines suggest that drivers should be able to average no more than about 10 mph below the average speed limit over a 10-hour period. For example, if the average speed limit is 55 mph, trips between 450 to 500 miles completed within 10 hours would be considered questionable, and trips of over 500 miles may be assumed to involve speeding. Carriers may be asked to prove that questionable runs can be completed without speeding.

Speed limiters: Speed limiters are not required at this time in the United States. However, they are required in parts of Canada.

Seat belts

Under federal regulations, all CMV drivers must wear seat belts while driving. Drivers are not exempted from wearing seat belts due to discomfort or medical conditions like claustrophobia.

Passengers on property-carrying vehicles must also wear their seat belts. Bus and motorcoach passengers are not required to wear seat belts.

Though seat belts must be used only when seat belts are installed by the manufacturer, most vehicles manufactured since 1965 needed to be equipped with seat belts. Removing an installed seat belt is prohibited.

• Buses transporting passengers, certain cargo tanks, and certain vehicles hauling hazardous materials must stop between 15 and 50 feet of all railroad crossings.
• All commercial motor vehicle (CMV) drivers must slow down enough to stop before railroad tracks if the driver sees that the course is not clear.
• Hazardous conditions include snow, ice, sleet, fog, mist, rain, dust, or smoke.

Railroad crossings

Certain CMVs are required to stop between 15 and 50 feet of all railroad crossings, to make sure the tracks are clear. This applies to buses transporting passengers, certain cargo tanks, and certain vehicles hauling hazardous materials, as listed in 392.10. The driver must not change gears while crossing the tracks.

All other CMV drivers, when approaching tracks, must slow down enough to be able to stop before the tracks if the driver sees that the course is not clear.

Finally, drivers may never drive onto a highway-rail grade crossing if there is not enough space to drive completely through the crossing without stopping.

Hazardous driving conditions

The CMV regulations require drivers to slow down and use “extreme caution” in hazardous conditions, such as snow, ice, sleet, fog, mist, rain, dust, or smoke. If conditions become bad enough, drivers must stop driving until it’s safe to drive again, unless stopping is more hazardous to passengers than continuing to the nearest safe area.

• When stopped on the shoulder or traveled part of the roadway, the commercial motor vehicle (CMV) driver must immediately turn on emergency warning flashers and, within no more than 10 minutes, place emergency warning devices on the roadway.
• The use of emergency warning flashers must continue until the emergency warning devices are in place.

CMV drivers who stop their vehicles on the shoulder or the traveled part of a roadway (other than for a normal traffic stop) need to minimize risks and alert other drivers to their presence. This is done by:

1. Stopping as far out of the way of other traffic as is safely possible;
2. Immediately turning on the vehicle’s emergency warning flashers; and
3. Within no more than 10 minutes, placing emergency warning devices.

Warning devices typically consist of 3 reflective triangles, but flares or “fusees” may also be used unless the vehicle is carrying explosives or a flammable gas or liquid, or uses compressed gas as a motor fuel. The following diagrams show how warning devices are to be placed, but see 392.22 for details.

Be aware that special rules apply to the use and placement of flame-producing emergency signals. See 392.22 through 392.25 for details.

Warning devices must be placed in the following order:

• No commercial motor vehicle (CMV), other than a bus, may transport a passenger without written authorization from the motor carrier.
• CMV drivers who wear corrective eye lenses or hearing aids to meet physical qualifications must always wear the lenses or hearing aids while driving.
• Drivers must not operate a CMV equipped with a radar detector.

The following table outlines several prohibited practices related to CMV driving.

• A defensive driver always looks ahead to locate potential hazards and avoid them.
• A defensive driver is aware of what is going on in front, behind, and to both sides of the vehicle.
• A defensive driver maintains a 10-foot cushion on both sides of the truck.

A defensive driver is a safe driver. Driving defensively prevents accidents and injuries as well as unexpected, additional business costs (vehicle repairs, increased insurance premiums, etc.).

Driving defensively means the driver keeps a constant visual scan. The driver stays alert to changes by looking well ahead, to the sides and behind the vehicle — observing the entire situation.

Recognizing potential hazards, deciding on an appropriate response, and carrying out the appropriate response are all key to defensive driving.

Four basic elements

The four basic elements of defensive driving are:

• Good vision — A defensive driver always looks ahead, identifying potential hazards quickly and applying the best way to avoid them. Looking ahead just doesn’t include what is directly in front of a vehicle, but rather 1–2 blocks ahead. Being seen is also just as important as seeing others. Drivers should make sure that lights, signals, and reflectors are in good working order.
• Heightened awareness — A defensive driver always knows what is going on in front, behind, and to the sides of the vehicle. Drivers should get into the habit of doing a constant visual scan around the truck. To do this effectively, drivers must clean and properly adjust the mirrors.
• Proper speed and space management — Maintaining an adequate cushion of safety around the truck is essential to defensive driving. This cushion is the driver’s margin for responding to hazards. It can take up to the length of two football fields to stop a commercial motor vehicle at highway speeds. Successful space management requires proper utilization of speed and following distance. A cushion of 10 feet of space should be on the sides of the truck.
• The right attitude — A good defensive driver assumes that the other drivers on the road aren’t paying attention. Distracted and inattentive drivers are a driver’s toughest challenge. Drivers must get in the habit of imagining “what if” at all times. Defensive driving means having the right attitude when driving. The driver is the only person in charge of safety!