Two-second rule two seconds as inadequate, and recommend a three-second rule. German law requires a minimum 0.9 second distance but when tested under relaxed conditions researchers found that their test subjects spent 41% of the test time at following distances under 0.9 second. The United States National Safety Council suggests that a three-second rule—with increases of one second per factor of driving difficulty—is more appropriate. Factors that make driving more difficult include poor lighting conditions (dawn and dusk are the most common); inclement weather (ice, rain, snow, fog, etc.), adverse traffic mix (heavy vehicles, slow vehicles, impaired drivers, pedestrians, bicyclists, etc.), and
Mischief rule they are interpreting. Driedger puts it this way: "[T]o this day, "Heydon's Case" is frequently cited. The courts still look for the 'mischief' and 'remedy', but now use what they find as aids to discover the meaning of what the legislature has said rather than to change it." Driedger goes on to argue that this modern use of the mischief rule ought to be understood as one of the components of what he characterized as the "modern" method of statutory construction, rather than a stand-alone rule serving (as it formerly had), as an alternative to the methods of construction proposed