Parents of this year's high school seniors have saved only 13% on average of the estimated $100,000 needed to pay for their child's four-year college education, says Fidelity Investments.

   And the three million seniors graduating this year who will go on to four-year schools will rely on public and private student loans to cover 17% of their total college expenses, according to Fidelity's research. And this at a time when student loans are getting harder to come by and might pack higher interest rates and stiffer terms.

   Add up it up, and Fidelity estimates this year's high school seniors could rack up a ton of debt to pay for four years of higher education, which could significantly impact their ability to begin their own savings plans after they graduate.

   One way to mitigate the problem is to invest in 529 plans, those tax-advantage investment vehicles designed to encourage saving for higher education expenses.

   Fidelity's research shows that parents of children ages 15-18, who currently utilize a 529 plan, are on track to cover almost half of their college expenses, says Joe Ciccariello, vice president of college planning, Fidelity Personal & Workplace Investing.

   At the same time, 60% of parents surveyed by Fidelity don't fully understand the impact that money in a dedicated college savings account can have in the financial aid formula. In fact, money in 529 plans has relatively little impact on financial aid because 529 assets are considered those of the parent, not the child.