Attentiveness, vigilance, perception of time and speed, and use of acquired knowledge are all affected by marijuana.
In fact, a meta-analysis of 60 studies concluded that marijuana causes impairment in every performance area that can reasonably be connected with safe driving of a vehicle, such as tracking, motor coordination, visual functions, and particularly complex tasks that require multi-tasking — although the research studies on how marijuana affects reaction time have been inconsistent.
Related Issues: Increased Crash Risk 2THC and Impairment 3