Note

Income Taxes

Income tax expense varies from the amount computed by applying the federal corporate income tax rates of

21%

and

35%

2018

and

2017,

respectively, to income before income taxes, primarily due to state income taxes, net of federal income tax effect, adjusted for permanent differences, the most significant of which is the effect of the per diem pay structure for drivers. Drivers who meet the requirements and elect to receive per diem generally receive non-taxable per diem pay in lieu of a portion of their taxable wages. This per diem program increases our drivers' net pay per mile, after taxes, while decreasing gross pay, before taxes. As a result, salaries, wages, and related expenses are slightly lower and our effective income tax rate is higher than the statutory rate. Generally, as pre-tax income or loss increases, the impact of the driver per diem program on our effective tax rate decreases, because aggregate per diem pay becomes smaller in relation to pre-tax income or loss, while in periods where earnings are at or near breakeven the impact of the per diem program on our effective tax rate is significant. Due to the partially nondeductible effect of per diem pay, our tax rate will fluctuate in future periods based on fluctuations in earnings.

Our liability recorded for uncertain tax positions as of

September 30, 2018

has decreased by

$0.1

million since

December 31, 2017.

The net deferred tax liability of

$73.3

million primarily relates to differences in cumulative book versus tax depreciation of property and equipment, partially off-set by net operating loss carryovers and insurance claims that have been reserved but

not

paid. The carrying value of our deferred tax assets assumes that we will be able to generate, based on certain estimates and assumptions, sufficient future taxable income in certain tax jurisdictions to utilize these deferred tax benefits. If these estimates and related assumptions change in the future, we

may

be required to establish a valuation allowance against the carrying value of the deferred tax assets, which would result in additional income tax expense. On a periodic basis, we assess the need for adjustment of the valuation allowance. Based on forecasted taxable income resulting from the reversal of deferred tax liabilities, primarily generated by accelerated depreciation for tax purposes in prior periods, and tax planning strategies available to us, a valuation allowance has been established at

September 30, 2018,

for

$0.1

million related to certain state net operating loss carry-forwards. If these estimates and related assumptions change in the future, we

may

be required to modify our valuation allowance against the carrying value of the deferred tax assets.

Provisional Amounts in the Effective Rate

The Tax Cuts and Jobs Act (the “Act”) was enacted on

December 22, 2017.

We are applying the Securities and Exchange Commission’s guidance in Staff Accounting Bulletin

No.

118

when accounting for the enactment-date effects of the Act. At

September 30, 2018,

we have

not

completed our accounting for all of the tax effects of the Act; however, as described below, we have made a reasonable estimate of the effects. During the

three

and

nine

months ended

September 30, 2018,

we recognized

adjustments to the provisional amounts recorded at

December 31, 2017.

We will continue to make and refine our calculations as additional analysis is completed, and as the states determine how they will coordinate and we receive the results of the federal carry back claim. Our estimates

may

also be affected as we gain a more thorough understanding of the tax law on a federal and state basis.

Deferred tax assets and liabilities: We remeasured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally

21%.

We also analyzed the future deductibility of restricted stock awards for executives and computed the effects of a net operating loss carryback to benefit the loss at

35%

in prior years. We recorded a provisional benefit amount of

$40.1

million as of

December 31, 2017

related to the remeasurement of certain deferred tax balances. For the

three

and

nine

months ended

September 30, 2018,

we have made

change to our analysis. We are still analyzing certain aspects of the Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. The provisional amount is also subject to change based on how states conform to the Act, as that information is

not

readily available for many states at this time.