Adds analysts' estimates to headline and paragraphs 1,8,9

April 29 (Reuters) - Trucking firm Old Dominion Freight Line's ODFL.O first-quarter profit surpassed analysts' estimates on Wednesday, as improved pricing mitigated the impact of lower shipment volumes.

One of the largest less-than-truckload firms in the U.S., Old Dominion said its revenue per shipment in the LTL segment, a gauge for pricing, rose 5.9% during the quarter.

Earlier this month, contract trucking firm J.B. Hunt JBHT.O said it was seeing signs of a recovery in trucking rates, led by a regulatory tightening of truckload capacity by drastically restricting commercial driver licenses to non-U.S. citizens. That led to the exit of foreign drivers and a handful of small players.

Some analysts, however, noted that companies are unlikely to reap any meaningful gains, with the improvement in truckload rates supply-driven, and not demand-driven.

U.S. trucking firms have been mired in a prolonged lull as excess supply pushed rates down, while operating costs kept climbing. Their challenges deepened over the past year as falling volumes and weakening demand were exacerbated by uncertainties surrounding the Trump administration's evolving trade policies.

Old Dominion's LTL shipments dropped 7.9% during the January-March quarter. The company earns nearly all of its revenue from the LTL services segment.

LTL involves carrying multiple shipments from different customers on a single truck, which are then routed through a network of service centers where they get transferred to other trucks with similar destinations.

The company's overall revenue dropped 2.9% to $1.33 billion. Still, it topped analysts' expectations of $1.31 billion, according to data compiled by LSEG.

Net income also fell to $1.14 per share from $1.19 a year ago, but beat the estimate of $1.05 per share.