Imagine a tire manufactured with material that will enable it to last two to five times longer than the one on your car today.

Imagine the same tire will retain its durability, be more round and more balanced even as it rolls off the assembly line. Now imagine that if the tire is punctured, it can travel about 200 miles before it needs replacing.

Amerityre Chief Executive Richard Steinke imagined such a tire -- a tire made out of polyurethane instead of rubber. And on April 22, Boulder City-based Amerityre received approval from the U.S. Department of Transportation to manufacture the tire.

"I had thought about different uses for polyurethane for at least 15 years," Steinke said. "And then after the Firestone problems, I set out to solve the inherent problems of rubber by making a better, rounder and more balanced tire," Steinke said.

Amerityre began testing a prototype tire in January for resistance, strength, endurance and high-speed performance. Results showed the material met minimum federal motor vehicle safety guidelines for new pneumatic tires.

From late 2000 through 2003, Amerityre began the initial stages of producing a series of prototype polyurethane tires. The tires were tested on a pickup at the Las Vegas Motor Speedway in late 2003. Government testing began in January.

Amerityre already manufactures more than 3 million flat-free polyurethane tires a year for bicycles, golf carts and other items.

The company is 9 years old and has 35 employees and more than $1 million dollars in annual revenues. The tire industry generates $23 billion a year.

Steinke said the company could begin manufacturing automotive tires today but instead will take on partners and license the technology to another manufacturer. He said that will allow Amerityre to conduct additional research and development tests.

Already, Goodyear has shown an interest in working with Amerityre to jointly develop a polyurethane tire for automotive use. The product will be featured in an upcoming episode of "Dateline NBC."

Steinke said the lack of heat buildup distinguishes the polyurethane tire from its rubber competitors. In a typical speed test over 80 mph, the temperature in a rubber tire can average 165 to 175 degrees.

"Heat buildup in a tire destroys the tire. The polyurethane tire reduces the heat by 30 degrees in speed tests conducted so far," Steinke said.

Production costs should be cheaper, he said, because the equipment to manufacture polyurethane tires will run one-tenth the cost of equipment needed to produce rubber tires.

Steinke also said the polyurethane tire is recyclable.

"We want our tires back after they are replaced. Our entire product line can be recycled," Steinke said, adding the polyurethane can be found in items such as bowling balls, surgical gloves and baby pacifiers. Consumer automotive officials hope to see polyurethane tires in the market within a year at prices comparable to traditional rubber tires. Steinke said the tires may be priced at a premium at first because of their uniqueness.