The incidence burden of unreported pedestrian crashes in Illinois

Communities with high rates of pedestrians struck by motor vehicles may miss out on mitigation resources and suffer worse medical outcomes if crashes there go unreported to police. This study investigates the places, people, and communities in Illinois where struck pedestrians are most likely to go unreported. A better understanding of the true burden and distribution of struck pedestrians will help guide policy and direct investments and interventions where they are most needed.

Hospital records of pedestrians treated for injuries sustained by a motor vehicle that were not able to be linked with a corresponding crash report across three consecutive years are investigated. Discordance rates of struck pedestrians are calculated and disaggregated by region. A presentation of summary statistics is accompanied by an ordinary least squares predictive model to estimate the relationship between discordant struck pedestrians and sociodemographic factors.

The incidence of unreported struck pedestrians was not randomly distributed. Blacks struck by a motor vehicle were disproportionately likely to go unreported to police. Zip codes with the most unreported crashes per capita on average had double the poverty rate and 2.6 times the carless household rate as the rest of Illinois. Struck pedestrians diagnosed at the hospital with an intoxicating substance went unreported to police nearly 70% of the time. Generally, more severe head and thorax injuries were more likely to be reported. Struck pedestrians outside of Cook County averaged a 60% discordance rate, those within Cook County averaged a discordance rate of about 50%. Struck pedestrian cases reported to police averaged emergency department charges of about $2,500 more than unreported cases.

Underlying and contributing factors influential of a struck pedestrian's decision of whether to report to police is complex and layered by social constructs mixed with difficult economic decisions, often further complicated by the fog of impairment. Recommendations are made for community outreach to stress the importance of reporting incidents to police, along with adjusting case count numbers in police records using hospital data and discordance rates.