This undated handout photo provided by the Placer County Sheriff's Department shows Brandon Rotolo. Rotolo, 24, has been arrested on suspicion of driving under the influence of marijuana and vehicular manslaughter after he allegedly struck and killed a motorist changing a flat tire along Interstate 80 last week near Sacramento, Calif. Law enforcement officials across the state fear this kind of tragedy may increase with the passage of Proposition 64 in Nov. 2016, which legalizes the recreational use of marijuana. (Placer County Sheriff's Department via AP))