The research she cites clearly indicates that drivers quickly adapt to the new features by increasing risky behaviors like driving faster, driving under poor conditions, or being less attentive and expecting the new technology to take care of them. She also points to drivers' lack of understanding of the limitations of the new assistive systems. The research he cites on human risk-taking indicates that there are large individual differences in risk homeostasis based upon personality, attitude and lifestyle. It appears that drivers are less interested in reducing risk than they are in optimizing it.
All drivers have a preferred level of risk which they maintain as a target.
When the level of risk they perceive in a situation goes down, they will adapt by raising their risky behavior so that the preferred target level remains constant over time. Technological improvements that drivers perceive as lowering the risk is thus followed by a change in behavior that is less cautious and raises the risk to the level prior to the improvement. The data discussed in Smiley's paper conform to this homeostatic explanation. Her solution calling for better driver understanding of the limitations of the new driver assistive technology may not work for the same reason. While driver training improves skill, it also increases confidence, which in turn lowers the perception of risk, and increases unsafe behavior.