AutoZone (NYSE:AZO) and O'Reilly Automotive (NASDAQ:ORLY) aren't the only ways to invest in the auto parts boom. After all, somebody has to put in all of these parts. That's where companies such as Universal Technical Institute (NYSE:UTI) come in. Universal Technical Institute describes itself as "a nationwide provider of technical education training for students seeking careers as professional automotive, diesel, collision repair, motorcycle and marine technicians."

Universal Technical Institute's results
Universal Technical Institute reported fourth-quarter results on Dec. 3. Revenue declined 5.4% to $95.8 million. Adjusted net income rose 12% to $1.8 million or $0.07 per share. New student growth jumped 9% during the quarter.

CEO Kim McWaters pointed out that the growth in net income and new students came despite "economic headwinds throughout the year." Universal Technical Institute generated more applications across all student segments, lowered its costs, and still improved its graduation rate. The company expects continued improvement in all three metrics for 2014, for which it believes it will be "able to achieve meaningful growth in operating results."

Conference call
During the call, McWaters explained that there has been an ongoing recovery in the transportation industry that, in turn, is now driving demand for technicians to work in the industry. She stated, "This is a very favorable trend and one that can have a very positive impact on our business. As demand grows, so does the need for employers to compete more effectively with each other to recruit and retain our graduates."

The next trends she sees are higher employment, higher wages, and the domino effect of more employer-paid training for employees to attend schools such as those that Universal Technical Institute provides. The Bureau of Labor Statistics sees 48,000 new job openings per year over the next five years in this industry. This all suggests that as long as the economy continues to improve, Universal Technical Institute's business will be a lagging factor that improves with the economy.

The relationship between Universal Technical Institute and AutoZone and O'Reilly Automotive
Demand for auto parts and demand for auto technicians don't necessarily have a one-to-one relationship. Rather, they are both driven by the rising demand in the transportation business. In other words, both industries benefit from the larger macro trends that are causing demand to trickle down.

AutoZone last quarter saw 5.6% sales growth to $3.1 billion for its fiscal fourth quarter. Same-store sales tacked on another 1%. AutoZone anticipates no slowdown in demand either; the company opened up another 153 stores this year alone. CEO William Rhodes stated, "We continue to see significant opportunities for new store growth." As long as you see demand for auto parts continue to escalate, you can bet this indicates a macro trend that benefits Universal Technical Institute as well.

Meanwhile, O'Reilly Automotive has been no laggard itself. The company saw a staggering 8% jump in sales to $1.73 billion last quarter. Same-store sales leaped 4.6% which CEO Greg Henslee referred to as "industry leading." Just like AutoZone, O'Reilly Automotive sees no sign of things slowing down and it is on pace to open 190 new stores in 2013 followed by 200 new stores in 2014.

Foolish final thoughts
Universal Technical Institute is a great way to play the auto parts boom. The company is looking great for 2014, but the stock itself may have gotten a little ahead of itself. It trades at nearly 40 times the analysts' earnings estimates for next year. Fools may want to take a peek, put Universal Technical Institute on their radar for now, and consider a position on a big pullback, assuming no change in the company's fundamentals.

Nickey Friedman has no position in any stocks mentioned. The Motley Fool owns shares of O'Reilly Automotive. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.