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
Uptick rule on 2009-04-08. A modified form of the rule was adopted on 2010-02-24. In 1938, the U.S. Securities and Exchange Commission (SEC) adopted the uptick rule, more formally known as "rule 10a-1", after conducting an inquiry into the effects of concentrated short selling during the market break of 1937. The original rule was implemented when Joseph P. Kennedy, Sr. was SEC commissioner. In 1994, the NASD and Nasdaq adopted their own short sale price tests, known as NASD Rule 3350, based on the last bid rather than on the last reported sale. In 1978, the purpose of the uptick rule was