The number of people killed by drunk drivers in Arizona went down slightly compared to last year -- but only because fewer people overall died on state roadways.

As a percentage of the total fatalities, more drunk drivers were responsible for killing people in 2012 than the year before, according to the Arizona Department of Transportation's Crash Facts annual report released this week.

The rate was already up slightly in 2011 from 2010 following a decrease in 2009, a New Times review of the last five years of reports shows. For injury crashes, the rate of drunk drivers believed responsible rose slightly in 2012.

Alberto Gutier, director of the Governor's Highway Safety office, had no explanation for why more drunk drivers, proportionately, are getting into crashes -- despite the fact that the state has, arguably, the harshest DUI laws in the country.

See also:

Marijuana By Itself Not a Significant Factor in Fatal and Injury Crashes in 2012, DPS Data Shows

As of the latest count, Gutier explains, a whopping 1,844 people are serving time in Arizona prisons because of DUI offenses. (The figure includes 1,581 U.S. citizens and 263 "criminal aliens.")

"That's a lot of people," Gutier notes, emphasizing that the figure doesn't include people serving time for DUIs in jail, like former Arizona Diamondbacks player Mark Grace.

Gutier speculates that perhaps an unrepentant "core" of alcoholics make up many of the drunk drivers in DUI-related fatal and injury crashes, and that it may be difficult to reduce the numbers much further on a consistent basis.

Also disheartening to Gutier, who oversees the dispersal of federal monies to help combat traffic injuries and deaths, is the rising number of fatal and injury crashes related to drivers impaired by drugs.

The 2008-2012 stats show that the rate of injury crashes attributable to drugged drivers has more than doubled. Fatal crashes due to drugged drivers have risen noticeably.

We've listed the figures for alcohol- and drugged-driving carnage below.

We'll also note that research for our recent articles on marijuana and driving indicate that the rise in drugged driving isn't due to a increase in marijuana-related crashes. For instance, the Arizona Department of Public Safety last year investigated just three marijuana-only fatal or injury crashes, yet investigated five times that number of fatal and injury crashes related to people who were illegally using drugs -- but had no booze or pot in their systems.

Our study for those pot-and-driving stories revealed evidence of the frightful trend in drugged driving: Phoenix police records shows that in two serious crashes last year, the suspects were driving on Versed, a light anesthesia that causes acute memory loss. We saw reports in which people were driving on Fentanyl, a super-opiate estimated to be more than 50 times as potent as morphine.

Often, our research showed, junkies were driving with an apothecary's-worth of drugs in their systems -- typically one or more kinds of tranquilizers combined with booze, pot or both.

"The most horrible ones are mixed," Gutier says, warning that booze and tranquilizers are probably the worst combo for drivers.

Drivers shouldn't just be concerned about serving time in prison or suffering through a year of being forced to blow into an interlock device in order to start their vehicles following a DUI conviction. They should wonder how they'll live with themselves if they kill or maim someone.

Click on the next page for the stats: (the years link to the corresponding ADOT Crash Fact reports):

Total roadway deaths in Arizona in 2012: 1,120 (down from 1,138 the year before)

Alcohol-related--------

% of total fatal crashes % of total injury crashes

2008 --------- 18.93 ------ 3.95

2009 --------- 19.41 ------ 3.88

2010 --------- 15.78 --- 3.56

2011 -------- 16.17 ---- 3.46

2012 -------- 18.39 ---- 3.49

Drug-related--------

% of total fatal crashes % of total injury crashes

2008 ------- 2.9 ------- .21

2009 -------- 3.55 ------- .4

2010 --------- 3.06 ---------- .42

2011 ----------- 3.51 ----------- .49

2012 ------------ 3.75 --------- .5

• DUI