Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their own strategies, so we are constantly looking at the latest trends in value, growth, and momentum to find strong companies for our readers.

Of these, value investing is easily one of the most popular ways to find great stocks in any market environment. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.

Luckily, Zacks has developed its own Style Scores system in an effort to find stocks with specific traits. Value investors will be interested in the system's "Value" category. Stocks with both "A" grades in the Value category and high Zacks Ranks are among the strongest value stocks on the market right now.

KnightSwift Transportation (KNX) is a stock many investors are watching right now. KNX is currently sporting a Zacks Rank of #2 (Buy) and an A for Value. The stock is trading with P/E ratio of 11.32 right now. For comparison, its industry sports an average P/E of 20.48. KNX's Forward P/E has been as high as 14.71 and as low as 11.32, with a median of 12.68, all within the past year.

Investors will also notice that KNX has a PEG ratio of 0.75. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. KNX's industry has an average PEG of 1.05 right now. Over the past 52 weeks, KNX's PEG has been as high as 0.98 and as low as 0.75, with a median of 0.85.

We should also highlight that KNX has a P/B ratio of 1.49. The P/B ratio pits a stock's market value against its book value, which is defined as total assets minus total liabilities. This stock's P/B looks solid versus its industry's average P/B of 4.31. Over the past 12 months, KNX's P/B has been as high as 1.62 and as low as 1.13, with a median of 1.35.

Finally, we should also recognize that KNX has a P/CF ratio of 8.01. This data point considers a firm's operating cash flow and is frequently used to find companies that are undervalued when considering their solid cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 17.99. Within the past 12 months, KNX's P/CF has been as high as 9.05 and as low as 6.69, with a median of 7.84.

Another great Transportation - Truck stock you could consider is USA Truck (USAK), which is a # 1 (Strong Buy) stock with a Value Score of A.