(

) Business Segments

We aggregate our

five

current operating segments into

four

reporting segments (Truckload, Dedicated, Intermodal and Brokerage) for financial reporting

purposes.

The primary source of our operating revenue is provided by our Truckload segment through a combination of regional short-haul and medium-to-long-haul ful

l-load transportation services. We transport food and other consumer packaged goods that require a temperature-controlled or insulated environment, along with dry freight, across the United States and into and out of Mexico and Canada.

Our Dedicated segment provides customized transportation solutions tailored to meet individual customers

’ requirements, utilizing temperature-controlled trailers, dry vans and other specialized equipment within the United States. Our agreements with customers range from

three

five

years and are subject to annual rate reviews.

Our Intermodal segment trans

ports our customers’ freight within the United States utilizing our temperature-controlled trailers on railroad flatcars for portions of trips, with the balance of the trips using our tractors or, to a lesser extent, contracted carriers.

Our Brokerage s

egment develops contractual relationships with and arranges for

third

-party carriers to transport freight for our customers in temperature-controlled trailers and dry vans within the United States and into and out of Mexico through Marten Transport Logistics, LLC, which was established in

2007

and operates pursuant to brokerage authority granted by the DOT. We retain the billing, collection and customer management responsibilities.

The following table sets forth for the periods indicated our operating r

evenue and operating income by segment. We do

not

prepare separate balance sheets by segment and, as a result, assets are

not

separately identifiable by segment.

	Three Months				Nine Months
	Ended September 30,				Ended September 30,
(Dollars in thousands)	2017		2016		2017		2016
Operating revenue:
Truckload revenue, net of fuel surcharge revenue	$	81,836	$	85,469	$	251,127	$	253,514
Truckload fuel surcharge revenue		10,172		9,726		31,453		25,771
Total Truckload revenue		92,008		95,195		282,580		279,285

Dedicated revenue, net of fuel surcharge revenue		39,154		37,669		114,654		109,833
Dedicated fuel surcharge revenue		2,995		2,967		9,274		7,175
Total Dedic ated revenue		42,149		40,636		123,928		117,008

Intermodal revenue, net of fuel surcharge revenue		17,423		16,381		51,111		48,353
Intermodal fuel surcharge revenue		2,472		1,979		7,085		4,990
Total Inter modal revenue		19,895		18,360		58,196		53,343

Brokerage revenue		16,627		16,273		50,645		48,847
Total opera ting revenue	$	170,679	$	170,464	$	515,349	$	498,483

Operating income:
Truckload	$	5,764	$	6,509	$	19,249	$	20,400
Dedicated		4,514		5,505		14,075		14,963
Intermodal		1,588		1,645		5,777		5,396
Brokerage		1,156		1,210		3,428		3,011
Total operating income	$	13,022	$	14,869	$	42,529	$	43,770

In the

three

-month periods ended

September 30, 2017

and

2016,

Truckload segment depreciation expense was

$14.1

million in each period, Dedicated segment depreciation expense was

$5.6

million and

$5.2

million, Intermodal segment depreciation expense was

$1.2

million and

$995,000,

and Brokerage segment depreciation expense was

$328,000

and

$400,000,

respectively. Truckload segment depreciation expense was

$43.1

million and

$41.7

million, Dedicated segment depreciation expense was

$16.4

million and

$15.3

million, Intermodal segment depreciation expense was

$3.4

million and

$2.9

million, and Brokerage segment depreciation expense was

$1.0

million and

$1.3

million, in the

nine

-month periods ended

September 30, 2017

and

2016,

respectively.