Tempe police say overall traffic collisions went down 3.9 percent in 2009 but fatal crashes in the city rose.
The Tempe Police Department's Traffic Bureau says nine fatal collisions occurred in 2010, up from seven in 2009.
Tempe police say an analysis of fatal collisions shows the most common traffic violation resulting in a fatal collision was speed and the most common type of collision was vehicle versus bicycle.
The most common age group for those involved in fatal collisions in Tempe was 21 to 25 years of age.
Police say 2010 showed an increase in the number of impaired persons involved in fatal collisions. Of the nine fatal collisions, four or 44% involved an impaired driver.
During 2009, 28 percent of the seven fatal collisions involved an impaired driver.