Among the five largest automakers in North America composed of the Honda Motor Co., the Toyota Motor Corp. and the Detroit Big Three, which participated in the latest Harbour Report, Toyota led the pack with the best overall manufacturing productivity. Additionally, the Honda of America Manufacturing Inc.'s Marysville assembly plant has received top stamping productivity commendation from an auto researcher.

Honda's Marysville plant, where the company produces the Accord sedan and coupe and Acura TL sedan, topped the list for stamping productivity. According to the Harbour Report, an annual study closely watched by Wall Street and industry analysts, the Japanese automaker also landed in first place for overall assembly performance in North America. The report divulged that each vehicle takes 21.1 hours to assemble.

Marysville-based Honda of America runs plants in Marysville, Russells Point, Anna and East Liberty and a research-and-development center in Raymond. The company makes the Honda Accord, Civic, Element and CR-V models and Acura TL and the RDX vehicles at its Central Ohio plants. About 13,700 workers in the area work on the improvement of its Honda body parts and product lines.

In 2006, General Motors and Honda posted the largest productivity gains among North American automakers, narrowing the gap with industry leader Toyota. GM also had a first with the most efficient plants in three of four categories measured in the study.

Toyota reclaimed the top spot from the Nissan Motor Co. in the Harbour Report. This was despite a two percent rise in the number of labor hours it took Toyota to build a vehicle. GM was fourth overall and highest among domestic manufacturers.

Toyota required 29.93 hours to build a vehicle last year, including stamping body parts, building the engine and transmission, and assembly. Nissan did not participate in this year's study, but Harbour estimated it needed 29.97 hours - 1.5 more than in 2005 - based on the number of workers versus output.

Honda increased by 2.7 percent to 31.63 hours, and GM 2.5 percent to 32.36. DaimlerChrysler improved 2.4 percent, to 32.9 hours, and Ford 1.9 percent, to 35.1. The domestic automakers, meanwhile, continued to narrow the gap with the Japanese automakers. In 2002, GM needed nearly eight more hours than Toyota to build a vehicle, and now it is less than 2.5. GM has knocked nearly 16 hours off the time it takes to build a vehicle since 1997, and Toyota has trimmed less than two.

Ron Harbour, the president of Harbour Consulting of Troy, Mich., predicted that massive job cuts this year at the three domestics would lead to additional productivity gains because fewer workers will build nearly the same number of vehicles. Harbour noted that several UAW locals have adopted such agreements, which also will be an issue this summer in contract talks.

GM was able to improve more because it had further to go, Harbour said. "When you get down to Toyota's level, you're not going to make double-digit improvements," he said. "It's really started to pay off."

Dan Sieger, a spokesman for the Toyota Motor Engineering & Manufacturing North America, would not comment on its productivity slip but said: "We look at a lot of different metrics, including our own studies, and we are always looking for ways to improve."

Toyota has expanded rapidly in North America and elsewhere and produced more vehicles than GM in the first quarter for the first time. Some analysts wonder whether Toyota is stretched too thin, but Sieger said, "There's no doubt our growth is a big challenge, but by all metrics our quality is still good and getting better."