Shares of National Interstate Corp., the Richfield, Ohio-based transportation insurer, climbed Tuesday after first-quarter profit improved on results at the unit covering recreational vehicles and commercial autos.

National Interstate has declined about 25% in the past year. Shares closed up 58 cents, or 3.8%, to $15.87, according to the Akron Beacon Journal.

Shares are down 31.4% from a year ago. For 2009, shares are down 11.2%.

First-quarter net income increased to a record $12.6 million, or 65 cents per share, from $9.6 million, or 49 cents a share, a year earlier. The quarterly earnings reflect a ”favorable” rate of claims per policy, the company said.

”Losses came in lower than expected,” said Robert Paun, an analyst at Sidoti & Co., who has a ”buy” rating for the insurer. ”The initiatives that they’ve implemented in reviewing their book of business late last year in the third and fourth quarters have really come through. We are expecting better underwriting margins going forward.”

Paun increased his full-year earnings-per-share estimate to $1.96 from $1.56. For 2010, he raised his projection 19% to $1.70 a share.