Exploring Trends and Patterns of Non-Compliant Crashes at Signalized Intersections in Phoenix, AZ

Abstract: Non-compliance behavior at traffic signals remains a significant safety concern, contributing to traffic crashes that often result in serious consequences. This study investigates patterns of non-compliant driving crashes at signalized intersections in Phoenix, Arizona, using crash data from the Arizona Crash Information System (ACIS), maintained by the Arizona Department of Transport (ADOT), for the years 2019 through 2023. The objective of the study is to identify key characteristics of non-compliance crashes, their severity levels, and contributing factors. Crash severity, assessed using the KABCO scale, revealed that 60.5% of incidents resulted in no injuries (O), while 17.8% involved possible injuries (C), 16.6% minor injuries (B), 3.9% serious injuries (A), and 1.1% fatal injuries (K). Notably, 59.5% of total incidents were angle collisions, two times more frequent than left-turn crashes (27%), highlighting the elevated risk of side-impact collisions at intersections. The time-of-day analysis showed that 67.3% of crashes occurred during the daytime (6 AM to 5:59 PM), while 32.7% took place at nighttime (6 PM to 5:59 AM). Although daytime crashes were more frequent due to higher traffic volumes, nighttime crashes tended to be more severe, likely due to poor visibility and speeding. Vehicle type analysis indicated that passenger cars were at-fault in 90.8% of non-compliant crashes. These findings underscore the need for strategic safety interventions at signalized intersections. Enhanced enforcement of red-light violations, improved nighttime visibility, and measures aimed at reducing angle collisions could significantly decrease the frequency and impact of non-compliant crashes.