This paper addresses priced managed lane corridors, on which travelers may choose to pay a toll to travel on the managed lanes (MLs) to realize generally faster, more reliable travel than on the adjacent, toll-free general purpose lanes (GPLs). These lanes exist in many cities across the United States and are becoming more common as transportation agencies look for innovative ways to increase capacity and regulate demand for their roadways. Commonly, demand for these lanes is modeled assuming travelers choose between the MLs and GPLs primarily based on the cost and time savings of the MLs. Although the traffic and revenue forecasts generated by these models have generally succeeded in estimating revenue, newly available empirical data from Katy Freeway and North Tarrant Express shows these models fail to capture how individual drivers make decisions. Most travelers on those freeways were not choosingthey always used the same lane regardless of travel time and toll. Travelers that used both sets of lanes often made choices that appeared counter-intuitive based on travel time savings and toll rate. This research provides a preliminary investigation into this issue, which calls into question all prior ML travel-behavior research.