This is hardly surprising as marijuana adversely affects self-control, judgement, and behavior. There have been studies relating being under the influence of marijuana to more aggressive behavior for a period of time after use and to homicides committed by users. It is likely that many of those in for marijuana possession pled down from more serious charges. An August 1997 study published in the Journal of the American Medical Association indicated that non-drug using people who live with illegal drug users have an 11 times greater chance of being the victim of a homicide than if they lived in a drug free home. It was 1.7 times higher if they lived with an alcohol user.
Common sense applies.
Alcohol is legal and dealing with crimes committed by those under its influence is the most expensive single expenditure of law enforcement funds and assets. It is estimated that between 7 to 10 times as many Americans use alcohol as use illegal drugs. If as many people were using marijuana and other illegal drugs as are using alcohol, the current rate of crime would pale by comparison to that rate. One of the most daunting things about marijuana is the potential for users to be involved in accidents. It was noted earlier, that many times as many people are current users of alcohol as are current marijuana users.