Here at Zacks, our focus is on the proven Zacks Rank system, which emphasizes earnings estimates and estimate revisions to find great stocks. Nevertheless, we are always paying attention to the latest value, growth, and momentum trends to underscore strong picks.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.One company value investors might notice is TravelCenters of America (TA). TA is currently sporting a Zacks Rank of #1 (Strong Buy), as well as a Value grade of A. The stock is trading with P/E ratio of 9.92 right now. For comparison, its industry sports an average P/E of 21.83. Over the past year, TA's Forward P/E has been as high as 23.81 and as low as 9.48, with a median of 12.52.Finally, investors should note that TA has a P/CF ratio of 3.08. This metric takes into account a company's operating cash flow and can be used to find stocks that are undervalued based on their solid cash outlook. TA's P/CF compares to its industry's average P/CF of 10.86. Within the past 12 months, TA's P/CF has been as high as 5.07 and as low as 2.38, with a median of 3.60.Value investors will likely look at more than just these metrics, but the above data helps show that TravelCenters of America is likely undervalued currently. And when considering the strength of its earnings outlook, TA sticks out at as one of the market's strongest value stocks. Zacks Names "Single Best Pick to Double" From thousands of stocks, 5 Zacks experts each have chosen their favorite to skyrocket +100% or more in months to come. From those 5, Director of Research Sheraz Mian hand-picks one to have the most explosive upside of all. It’s a little-known chemical company that’s up 65% over last year, yet still dirt cheap. With unrelenting demand, soaring 2022 earnings estimates, and $1.5 billion for repurchasing shares, retail investors could jump in at any time. This company could rival or surpass other recent Zacks’ Stocks Set to Double like Boston Beer Company which shot up +143.0% in little more than 9 months and NVIDIA which boomed +175.9% in one year.Free: See Our Top Stock and 4 Runners Up >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report TravelCenters of America LLC (TA): Free Stock Analysis ReportTo read this article on Zacks.com click here.Zacks Investment Research