It was race night at the NASCAR track in Richmond, Va., four years ago and Terri Livingston Kozel and Lori A. Livingston were on the hunt for T-shirts and other gear featuring their favorite drivers, Rusty Wallace and Carl Edwards. Avid racing fans who had followed the sport since they traveled to races with their dad as kids, the sisters were disappointed at each vendor they visited. They found the women's apparel unfashionable, and the men's T-shirts they liked were so long they couldn't tuck them in. 'There was nothing edgy or fashionable,' Livingston said. 'Nothing we wanted to wear.' The women, who own Pine Away, a home design and accessories shop in Annapolis, Md., went home after the race and began sketching designs of clothing they thought would better appeal to female NASCAR fans. The women's disgruntlement has evolved into Flag2Flag Apparel, a line of NASCAR denim fashion aimed at women that they began selling more than a year ago. The line includes denim skirts with drivers' numbers and signatures, and jeans with metal studs that run down the leg. The company has the rights to make products for several drivers, including Kyle Petty and Greg Biffle. It will soon introduce a line of clothing for Kasey Kahne. Female fans of professional sports were once an afterthought to the companies that manufacture sports apparel and souvenirs. But as companies look for new niches and the female fan base continues to grow, more sports apparel has been aimed at women. The National Basketball Association has a line called 'nba4her,' and the NFL has pink jerseys. Even NASCAR, which has a $2 billion annual licensing business, has improved its selection of women's attire, said Tom Sullivan, manager of business communications for the Florida-based racing venture. About 40 percent of NASCAR fans are women, a number that has remained steady during the past few years, even as the overall fan base has dipped because of the economy and other reasons. Livingston and Kozel's father, Jay Livingston, raced cars in Maryland and Virginia in the mid-1960s. He competed in NASCAR Late Model and Grand National events for more than 15 years. While his sons didn't take a keen interest in the sport, his daughters always tagged along and developed a passion for racing. 'It's the speed of the cars, the friendships you develop and the excitement of being at the track,' Kozel said. 'It just becomes a part of your roots.' Kozel and Livingston think there is room for growth in the women's NASCAR apparel market, and some sports marketing experts agree. 'The sporting goods industry is a good old boys' industry, and they treat women as if they are little men,' said Matt Powell, an analyst for SportsOneSource, which tracks sports apparel sales. 'Clearly, women are a growing fan base in all sports. If there is a product that actually fits her, she will gravitate toward it.' It was a slow start for Flag2Flag when it was breaking into the NASCAR apparel business. While the sisters were experts in interior design, clothing design was new territory. The sisters decided early on to have a denim line instead of T-shirts or other apparel because 'that's what everyone wears in the stands,' Kozel said. Livingston spent months visiting denim 'wash houses' in California, learning the process of manufacturing denim. They got financing for the business from a banker their father dealt with, who told them he wouldn't touch the business if it weren't for that relationship. The sisters found a facility in Mexico that does manufacturing for Levi's as well. But the biggest obstacle was breaking into the competitive world of NASCAR licensing. The racing company works with more than 200 licensees who sell about $2 billion worth of products that include everything from car mufflers to flash drives, toys and T-shirts. NASCAR gives its own licensing for a driver's number and car, which the racing company owns. But the racing teams also often sign license agreements that allow companies to use a driver's image. Kozel and Livingston were having a hard time breaking into NASCAR licensing until the wife of a Nextel executive came to Pine Away one day and heard about their venture. The woman connected them with her husband, who gave them contacts at NASCAR. Livingston remembers clearly the response she got from NASCAR when they called. 'Send us the stuff, but understand this is a hard process and it may be years before you get through it,' they were told. They mailed some samples on a Friday. To their surprise, by Monday they were told they would be able to sell. The sisters would like to make the NASCAR clothing line their entire business one day, but for now it's still an effort. Even with the NASCAR licensing, they still have to get the rights from the teams as well, the sisters said. Some of the teams already have rights with other companies. For instance, Motorsports Authentic said on its Web site that it has license agreements 'with the most recognized names in NASCAR such as: Dale Earnhardt Jr., Jeff Gordon, Jimmie Johnson, Tony Stewart, Kevin Harvick, Carl Edwards and Kasey Kahne.' 'Sometimes teams will tell us, `We'd like to, but let's see how you do elsewhere,' ' Livingston said. Livingston and Kozel spend weekends hitting racetracks around the country, schmoozing with teams and building a rapport that they hope will lead to future business. Their marketing is grass-roots. They walk through the crowds wearing their styles and giving out cards. They also use Facebook and Twitter and have been included in some NASCAR fan guides. They sell mostly on the Internet at Amazon.com and at the superstore at nascar.com. They also have their own Web site (flag2flagapparel.com). Livingston and Kozel declined to release sales figures and have said they have yet to make a profit, but hope that day will come. They also hope to expand the line when the time is right. 'We want to get good at one thing first,' Livingston said. 'Then we'll go from there.' 