Task Difficulty Homeostasis

There are however several models of driver behaviour that have dominated theoretical discussions in the last decade or so (Table 4.1). These are task difficulty homeostasis theory (TDH) (Fuller and Santos, 2002 Fuller, 2005, 2007 Fuller et al., 2008a,b), its successor risk allostasis theory (RAT) (Fuller, 2008, 2011), the risk monitor model (RMM) (Vaa et al., 2000 Vaa, 2003, 2007, 2013) and the multiple comfort zone model (Summala, 2005,2007). As such, the majority of this chapter is dedicated to covering these models, which we hope will highlight trends in theory development since 2000 (see Table 4.1). One such trend was movement away from theories that relied on risk . This was initially hailed as a long overdue step forward (Rothengatter, 2002) however, this trend did not necessarily continue. We will return to this issue in subsequent sections of the chapter. 

FIGURE 4.2 Task difficulty homeostasis theory. (From Fuller, R. et al. 2008a. The Conditions for Inappropriate High Speed—A Review of the Research Literature from 1995 to 2006. London Department for Transport. With permission.)... 

FIGURE 4.3 Risk allostasis theory. (From Handbook of Traffic Psychology, Fuller, R., Driver control theory From task difficulty homeostasis to risk allostasis, pp. 13-26, Waltham, MA Academic Press, Copyright 2011, with permission from Elsevier.)... 

Chapter 4 summarises the risk allostasis theory and its development from task difficulty homeostasis (Fuller, 2005a,b) as part of a review of contemporary theories. 

RAT evolved from task difficulty homeostasis and it is, therefore, important to understand the meaning of this change. Allostasis is defined as ... 

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