Nebraska-based truckload fleet Werner Enterprises reported a drop in its third quarter profit amid just a slight increase in business.

Net income fell to $21.3 million from $25.1 million the same time a year ago, a 15% decline.

Total revenue during the same time increased 1% to $512 million from $507 million, but trucking revenue, net of fuel surcharge, fell 1% to $322 million from $326 million.

Werner points out average revenues per total mile, net of fuel surcharge, rose 2.4% in third quarter 2013, compared to third quarter 2012.

“We believe there are several truckload capacity constraints including an older industry truck fleet, the higher cost of new trucks and trailers, significant safety regulatory changes and a challenging driver market,” it said in a release.

Werner says hours of service rules changes that took effect in July negatively impacted miles per truck by 2% to 3%.

For the first nine-months of the year Werner had net income of nearly $65 million, a 16% decline from just over $77 million from the same time last year, while revenue fell 1% to $1.511 billion from $1.527 billion.

More information is on the Werner Enterprises website.