Investors interested in stocks from the Transportation - Truck sector have probably already heard of Knight-Swift Transportation Holdings (KNX Quick QuoteKNX - Free Report) and Old Dominion Freight Line (ODFL Quick QuoteODFL - Free Report) . But which of these two stocks offers value investors a better bang for their buck right now? We'll need to take a closer look.

We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The proven Zacks Rank emphasizes companies with positive estimate revision trends, and our Style Scores highlight stocks with specific traits.

Knight-Swift Transportation Holdings has a Zacks Rank of #2 (Buy), while Old Dominion Freight Line has a Zacks Rank of #3 (Hold) right now. This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that KNX is likely seeing its earnings outlook improve to a greater extent. But this is just one piece of the puzzle for value investors.

Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.

The Value category of the Style Scores system identifies undervalued companies by looking at a number of key metrics. These include the long-favored P/E ratio, P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that help us determine a company's fair value.

KNX currently has a forward P/E ratio of 12.54, while ODFL has a forward P/E of 32.85. We also note that KNX has a PEG ratio of 0.84. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. ODFL currently has a PEG ratio of 1.45.

Another notable valuation metric for KNX is its P/B ratio of 1.35. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, ODFL has a P/B of 9.42.

These are just a few of the metrics contributing to KNX's Value grade of A and ODFL's Value grade of D.

KNX has seen stronger estimate revision activity and sports more attractive valuation metrics than ODFL, so it seems like value investors will conclude that KNX is the superior option right now.