— Speed -- the No. 1 factor in crashes in Alabama -- and traffic volumes raise the risk of fatal accidents. Where those two elements combine, there are identifiable pockets of higher occurrences, crash data for Jefferson and Shelby counties show.
Between 2007 and 2011, 537 fatal crashes in those two counties killed 590 people, according to the latest complete data from the National Highway Traffic Safety Administration's census of fatal wreck records.
Data show the number of fatal crashes trending upward toward the end of that period, though stronger laws intended to improve driver behavior could reverse the trend, analysts say.
. Interstate 20/59 at Arkadelphia Road: 12 crashes, 13 deaths. Annual average daily traffic figures from 2011 show up to 141,000 vehicles per day along I-20/59; 40,000 along Arkadelphia Road north of the interstate.
. Interstate 65/Interstate 459 interchange: Seven crashes, 10 deaths. Traffic count at the edges of the interchange show 106,000 vehicles per day pass along I-459; 110,000 to 115,000 along I-65.
. Interstate 20/59 between First Avenue North and Roebuck Parkway: Seven crashes, seven deaths. Three were single-vehicle crashes. Traffic ranges from about 55,000 vehicles per day near Roebuck Parkway to about 70,000 near First Avenue.
. U.S. 78 (Forestdale Boulevard) roughly from Cherry Avenue to Dugan Avenue: Six crashes, Six deaths. Two involved pedestrians. Traffic count for that stretch, 40,000 to 45,000 vehicles per day.
. Interstate 65-Interstate 20/59 ("Malfunction Junction") interchange: Six crashes, six deaths. Three were single-vehicle crashes, one involved a pedestrian. Traffic count up to 157,000 vehicles per day along I-20/59 and about 126,000 near the junction.
. Interstate 20/59 at Tallapoosa Street: Five crashes, Five deaths. On average, up to 151,000 vehicles per day pass through that stretch. Tallapoosa Street averaged about 51,000 at the interchange. Three of the crashes involved drivers striking the sides of other vehicles headed in the same direction, data show.
But fatal crashes give only a partial snapshot said Dave Brown, deputy director of the University of Alabama's Center for Advanced Public Safety.