Every four years, the American Society of Civil Engineers issues a report card on the condition of the nation's infrastructure. In 2013, the country received a sad D+ – something that then-candidate Donald Trump highlighted during his presidential campaign. The recently released 2017 report card is no better – another D+.

However, as president, Trump has promised up to $1 trillion in new spending to spruce up the nation's crumbling infrastructure, a prospect that should encourage investors who seek exposure to this niche. (See: How Big Investors Will Profit From Trump's Infrastructure Bonanza.)

It is important to note that infrastructure is an extremely broad category, encompassing transportation, communications, water and electricity – representing hundreds, if not thousands, of equities. Selection is essential to success, since not all "infrastructure" stocks will take off under the proposed spending. (See: Build Your Portfolio With Infrastructure Investments.)

That being said, well-diversified companies positioned to handle major infrastructure projects should do well over the medium to long term, especially if the administration follows through with its spending commitment. Here's a look at four of the most promising infrastructure stocks. All figures are accurate as of December 27, 2017.

AECOM (ACM)

AECOM's business is designing, financing, building and operating infrastructure assets for federal and state governments and businesses. With a market cap of $5.89 billion and fiscal 2016 annual revenue of $17.47 billion, the company is well positioned to handle a large influx of new government projects.

AECOM recently merged with rival URS to enhance its focus on the energy and transportation sectors, areas that are sure to see new spending under the Trump administration if the president can pass his infrastructure package. In fact, AECOM stock surged sharply on Trump's victory, rising from $27.61 on Nov. 8, 2016, to $37.54 a week later, reaching a high of over $40 in December 2016. As of December 27, 2017, the stock was trading at $37.38, up less than 3% year-to-date. The stock has a median 12-month price target of $39.88, suggesting 6% upside potential, and it earns a consensus rating of "Buy." (See also: AECOM to Buy Shimmick, Make Most of Infrastructure Spend.)

Vulcan Materials Company (VMC)

"Construction aggregate" sounds like a boring business, but these little bits of gravel, limestone and sand form the foundation of all sorts of building projects, including high-priority infrastructure items such as bridges, roads and industrial plants. Vulcan is the largest producer of these construction products, and it estimates that 75% of the population growth in the coming years will take place in states currently served by the company.

Vulcan has a market cap of $16 billion and generated annual revenue of $3.59 billion in 2016, which equates to a revenue growth rate of nearly 9% year over year. As of December 27, the stock was trading at $127.48, a year-to-date rise of less than 2%. Its median price target is $140.54 (implying 10% upside potential), and the consensus rating is Outperform. (See also: Vulcan Materials' Inorganic Growth in Full Swing.)

Martin Marietta Materials, Inc. (MLM)

Martin Marietta is a leading manufacturer of cement, asphalt and other building materials, with a strong presence in states such as North Carolina, Texas, Colorado and Georgia that have booming construction economies. The company recently kicked off a massive project in Texas known as the Medina Rock & Rail, strengthening its foothold in the lucrative Texas market. Last year proved to be a record year in terms of the company's revenue, which hit nearly $3.9 billion.

Martin Marietta is based in Raleigh, North Carolina, and it has a market cap of nearly $13.72 billion. Net income was up last year by 47% to $421 million, and earnings per share rose 31% to $6.63. The stock currently trades at $218.20, down 1.5% year-to-date. The average 12-month price target of $239.50 suggests upside potential of nearly 10%. (See also: Martin Marietta to Buy Bluegrass, Boost Aggregates Business.)

Quanta Services, Inc. (PWR)

Quanta is a specialty contractor providing infrastructure services primarily to the oil and gas and electrical power industries, all of which stand to benefit under Trump's infrastructure spending plans. Quanta is also a prime provider of oil and gas pipelines and renewable energy infrastructure, including onshore and inland hydroelectric projects.

Quanta has a market cap of $5.5 billion and posted annual revenue of $7.65 billion in 2016, on par with the previous year's revenue of $7.57 billion. As of December 27, the stock was trading at $39.48, up 13% year-to-date. Its 12-month price target of $44.46 leaves room for over 13% growth. (See also: Quanta Services Q1 Earnings Miss, Revenue Up Y/Y.)

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