Investors looking for stocks in the Transportation - Truck sector might want to consider either Knight-Swift Transportation Holdings (KNX Quick QuoteKNX - Free Report) or Old Dominion Freight Line (ODFL Quick QuoteODFL - Free Report) . But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.

There are plenty of strategies for discovering value stocks, but we have found that pairing a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system produces the best returns. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.

Knight-Swift Transportation Holdings and Old Dominion Freight Line are sporting Zacks Ranks of #1 (Strong Buy) and #3 (Hold), respectively, 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. However, value investors will care about much more than just this.

Value investors also try to analyze a wide range of traditional figures and metrics to help determine whether a company is undervalued at its current share price levels.

Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.

KNX currently has a forward P/E ratio of 14.81, while ODFL has a forward P/E of 35.23. We also note that KNX has a PEG ratio of 0.99. 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 2.26.

Another notable valuation metric for KNX is its P/B ratio of 1.16. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, ODFL has a P/B of 7.30.

These metrics, and several others, help KNX earn a Value grade of A, while ODFL has been given a Value grade of C.

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.