Navistar International Corp., the world's fourth-largest truckmaker, is offering $2,500 in incentives on heavy-duty trucks as stricter emissions regulations take effect Oct. 1, Bloomberg News reports.

Buyers of International 8000 Series and 9000i models can take the incentive in financing discounts, a trade-in allowance bonus or a parts and service credit. The trucks sell for $80,000 to $125,000 each.

North American heavy-truck orders rose 53 percent this year through August from a year earlier as trucking companies moved up orders, analysts have said. Monthly orders peaked in March at 29,133, but by last month had fallen to 7,071, they said.