“…The amount of TTC underestimation increases as the actual TTC increases, which raises questions about the usability of TTC in shaping human performance (Caird & Hancock, 1994;Schiff & Detwiler, 1979). The accuracy of TTC estimation depends on several factors, including the closing speed (Kiefer, Flannagan, & Jerome, 2006;McLeod & Ross, 1983;Sidaway, Fairweather, Sekiya, & McNitt-Gray, 1996) and the front object size (Caird & Hancock, 1994;DeLucia, 1991;DeLucia & Warren, 1994). Smeets, Brenner, Trebuchet, and Mestre (1996) suggested that humans do not perceive TTC directly, but infer TTC using the perceived relative speed and distance with respect to the front object.…”