Why The Iconic Semi-Truck Was Discontinued, Although Beloved

With its distinctive cab-over-engine design, the Kenworth K100 was once a symbol of the open road and a favorite among long-haul drivers. Known for its rugged reliability, recognizable style, and for being the semi-truck that inspired Optimus Prime, the K100 was a truly legendary semi-truck. But its disappearance had more to do with shifting industry demands than a decline in popularity.

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The Kenworth K100’s appeal dropped after the maximum allowed length of a semi-truck and trailer changed from 65 feet to 75 feet in 1976. Up to that point, the K100 had been a go-to big rig among trucking companies, as the shorter cab-over design let them save length on the cab and use it for the trailer instead. The increased length limit eliminated this advantage, and Kenworth officially discontinued the K100 line of semi-trucks in 2002. Another iconic Kenworth semi-truck, the W900, was discontinued in 2025, though for different reasons.

Despite discontinuing the K100 in North America, Kenworth kept building the semi-truck for the Australian market. Kenworth followed the K100 with the K200, which was essentially the same truck. Kenworth Australia later introduced the K220, another cab-over semi-truck that serves as the modern equivalent of its iconic predecessor.

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The Kenworth K100 semi-truck became a staple of 1970’s pop culture due to the hit TV series BJ and the Bear, where a red and white version was featured in nearly every episode. The K100 also gained notoriety for moving the Enterprise space shuttle in Alabama, in a showcase of the truck’s power. But the K100’s cab-over-engine design shared the same drawbacks as other similarly built semi-trucks.

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Cab-over semi trucks were typically noisy, as the driver sat above the engine. The cab itself wasn’t very comfortable, and though companies did address this issue, those improvements led to higher-priced rigs. But the biggest problem was safety, as there was very little to protect the driver during a head-on collision, especially when compared to a long-hood truck.

But Kenworth is still one of the most popular semi-truck brands in America, and the K100 remains a popular truck for its nostalgic appeal and its performance. Thanks to business owners keeping the K100 on the road, this iconic rig will undoubtedly remain a presence on American highways for years to come.