Arizona reached a 15-year high in traffic deaths last year, state transportation officials said Wednesday.

The number of those killed in traffic collisions rose from 1,054 in 2020 to 1,180 in 2021, an increase of 12%, according to the Arizona Department of Transportation.

The total number of traffic crashes also rose by 22% as people drove an estimated 8.1 billion more miles last year than in 2020.

The figures come from the Arizona Motor Vehicle Crash Facts report report.

The annual report is a compilation of traffic crash reports provided by law enforcement agencies around the state. The document reflects reported crash data for all Arizona roadways, including city streets, county roads, reservation roads and state highways, according to ADOT.

“The 2021 report shows an increase in all categories in terms of number of crashes, injuries and fatalities over 2020 as more people began to travel once again to work, school and other places,” the report states.

A month-by-month breakdown in the crash report shows an overall increase in the number of crashes as the year went on, with October being the peak month for crashes.

Fatalities are driven mostly by driver behavior.

Speed was a factor in 30% of all fatalities last year, and impairment was a factor in nearly one-third of all traffic fatalities in 2021. Not wearing seat belts was a factor in almost one-quarter of all fatalities.

“This illustrates that real change must begin in the driver’s seat,” the ADOT report states.

“Reducing crashes, fatalities and injuries can’t be solved by state agencies alone because more than two-thirds of crashes occur on roads other than state highways.”

Alcohol-related crashes rose in 2021 with 5,620 crashes, a number not seen since 2009, which had 5,905 crashes.

The number of alcohol-related fatalities also saw a slight rise with 243 deaths in 2021 compared to 228 in 2020 – a 6.5% increase reversing recent downward trends in alcohol-related fatalities between 2017 and 2020, according to the report.

Bicycle-related fatalities also increased with 45 fatalities in 2021, a 41% increase over the 32 deaths in 2020. Bicycle-related fatalities have risen each year since 2018.