I just looked up the Requirements in the CDL handbook for Texas.
Who needs a Commercial Driver License?
All drivers who operate a commercial motor vehicle (see
definition on page 1-1) will be required to have a
Commercial Driver License (CDL) by April 1, 1992. The law
does provide for some exemptions. If the driver meets one
or more of the criteria listed below, he will not be required to
have a CDL. However, the driver will be required to have a
Class A, B, or C Non-CDL License.
Who is exempt from a CDL? (Certification form CDL-2
required)
Persons operating the following vehicles are exempt from a
Commercial Driver License:
1. A vehicle that is controlled and operated by a farmer;
and used to transport agricultural products, farm machinery, or farm supplies to or from a farm; and not used in
the operations of a common or contract motor carrier; and
used within 150 air miles of the person’s farm.
2. A fire-fighting or emergency vehicle necessary to the
preservation of life or property or the execution of emergency governmental functions, whether operated by an
employee of a political subdivision or by a volunteer fire
fighter (this includes operators of industrial emergency
vehicles);
3. A military vehicle, when operated for military purposes
by military personnel, members of the Reserves and
National Guard on active duty, including personnel on
full-time National Guard duty, personnel on part-time
training, and National Guard military technicians; or
4. A recreational vehicle that is driven for personal use.
5. A vehicle that is owned, leased, or controlled by an air
carrier, as defined by Texas Transportation Code (TRC),
Section 21.155, and that is driven or operated exclusively by an employee of the air carrier only on the premises
of an airport, as defined by the TRC, Section 22.001, on
service roads to which the public does not have access.
6. A vehicle used exclusively to transport seed cotton
modules or cotton burrs.
Page 1-1
There is a federal requirement that each state have minimum standards for the licensing of commercial drivers. This
manual provides driver license testing information for drivers
who wish to have a commercial driver license (CDL). This
manual does NOT provide information on all the federal and
state requirements needed before you can drive a commercial motor vehicle (CMV). You may have to contact your
state driver licensing authority for additional information.
You must have a CDL to operate:
1.A single vehicle with a gross vehicle weight rating GVWR
of more than 26,000 pounds.
2.A trailer with a GVWR of more than 10,000 pounds if the
gross combination weight rating is more than 26,000
pounds.
3.A vehicle designed to transport more than 15 persons
including the driver.
4.Any size vehicle which requires hazardous materials
placards.
(Your state may have additional definitions of CMVs.)
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The way I interpret #2 is this, if you have a trailer that has a GVWR of 10,400 pounds( >10K) and your tow vehicle has a GVWR of 16,000 pounds (> 26K gross combined weight), the driver needs a CDL.
BTW, A 2012 Ford F350 has a GVWR of 13,300 lbs, 2012 Dodge Ram 3500 has a GVWR of 12,200 lbs, and a 2013 Chev\GMC has a GVWR of 13,025 lbs. So if your trailer has a GVWR of 14,000lbs, a CDL is required.
http://www.txdps.state.tx.us/DriverLicense/documents/DL-7C.pdf