Montana, the state that rejected speed limits, is heading toward a lot more traffic. According to a recent report, the number of miles traveled by car in Montana grew twice as fast as population from 1970 to 1990 and is projected to double again by 2015. With 1.7 cars per licensed driver, Montana residents already own more vehicles than anywhere else in the nation. Although the state is vast, Montana's population isn't as far-flung as you'd think: 75 percent of the population lives in or near the 10 largest towns. Still, Montanans are driving more miles than ever, and most of their driving is local, causing congestion on central roadways. The Big Sky state also boasts abundant parking lots; capital Helena, for example, has almost 150,000 spots, nearly six for each resident of the city. The report by the Helena-based Alternative Energy Resources Organization concentrates more on describing current land-use patterns that spur sprawl than imagining solutions. Still, it's worth knowing that since 1960, Helena has spread an acre for each new resident and is still growing. A 15-page summary of the report, Big Sky or Big Sprawl: What Transportation and Land-Use Decisions Cost Montana Communities, is available for $4; the full report costs $15. Contact AERO at 25 S. Ewing, Suite 214, Helena, MT 59601 (406/443-7272) or e-mail aero@desktop.org.