This study compared freeway crashes that involved older drivers (ages 66 and older) with those that involved middle-aged drives (ages 31 through 45). Data from five HSIS states - Illinois, Maine, Michigan, Minnesota, and Utah - were used. A total of 40,297 crashes were used in the analysis: 36,142 crashes for drivers ages 31 to 45, and 4,155 crashes for drivers age 66 and older. To help control for the lack of exposure data, "paired-vehicle" analyses were performed for the 2,516 crashes that involved one older and one younger driver. Compared to their younger counterparts, older drivers were more likely to be changing lanes, were five times as likely to be cited for failure to yield while changing lanes, and were over-involved in run-off-road, single-vehicle crashes. Older drivers were also more likely to be injured or killed in freeway crashes.