Traffic accidents and public health: Preventable mortality estimates from interrupted time series and panel evidence in Türkiye, 2009–2023

Abstract

This study aims to quantify the public health burden of road traffic fatalities and injuries in Türkiye between 2009 and 2023, with particular attention to the definitional change in 2015 (30-day rule) and the COVID-19 shock in 2020. Using an interrupted time-series (ITS) design, annual deaths per million population (DPM, log-transformed) were modeled through segmented OLS with Newey–West standard errors, incorporating level and slope changes. Diagnostics included ACF/PACF and Ljung–Box tests. Counterfactual deaths for 2020–2023 were generated from the 2012–2019 trend. Findings indicate a significant upward level shift in 2015 (+0.89 log-DPM, p<0.001), a downward shock in 2020 (−0.30, p<0.001), and a post-2020 positive slope change (+0.17 per year, p<0.001). Observed DPM consistently remained below counterfactual expectations during 2020–2023 (e.g., 58 vs. 97 in 2020). Case fatality ratio (CFR) rose from 1.38% in 2012 to 1.83% in 2023, with peaks in summer and marked regional heterogeneity. The results demonstrate that measurement standardization and exposure shocks strongly influence mortality trends, whereas the increasing post-pandemic slope indicates a renewed escalation of traffic-related risks. These findings highlight the need for targeted policy packages integrating speed management, behavioral adaptation strategies, and comprehensive trauma care systems.

Keywords

• Road traffic crashes
• public health
• interrupted time series (ITS)
• counterfactual analysis
• case-fatality ratio (CFR)

Trafik kazaları ve halk sağlığı: 2009–2023 yılları kesintili zaman serisi ve panel bulgularına dayalı önlenebilir ölüm tahminleri

Abstract

Bu çalışma, 2009–2023 döneminde Türkiye’de karayolu trafik kazalarına bağlı ölümlerin ve yaralanmaların halk sağlığı yükünü nicel olarak ortaya koymayı amaçlamaktadır. Özellikle 2015 yılındaki tanımsal değişiklik (30-gün standardı) ve 2020’deki COVID-19 pandemisi şoku, kesintili zaman serisi (KZS) yaklaşımıyla incelenmiştir. Bağımlı değişken olarak milyon nüfus başına ölüm (DPM, log-dönüşümlü) kullanılmış; Newey–West standart hatalarıyla tahmin edilen segmentli OLS modeline seviye ve eğim kırılmaları dahil edilmiştir. Artık yapısı ACF/PACF ve Ljung–Box testleriyle değerlendirilmiş; karşı-olgusal ölümler 2012–2019 eğiliminden türetilmiştir. Bulgular, 2015’te anlamlı bir düzey artışı (+0.89 log-DPM, p<0,001), 2020’de düzey düşüşü (−0.30, p<0,001) ve 2020 sonrasında pozitif eğim değişimi (+0.17/yıl, p<0,001) olduğunu göstermektedir. 2020–2023’te gözlenen DPM, beklenen değerlerin altında kalmıştır (örn. 2020’de 58 gözlenen vs 97 beklenen). Olgu-ölüm oranı (CFR) 2012’de %1,38’den 2023’te %1,83’e yükselmiş; yaz aylarında zirve yapan mevsimsel desenler ve iller arasında belirgin farklılıklar saptanmıştır. Sonuçlar, ölçüm standardizasyonu ve maruziyet şoklarının eğilimleri güçlü biçimde etkilediğini, pandemi sonrası eğim artışının ise risklerin yeniden yükseldiğine işaret ettiğini göstermektedir. Bulgular, hız yönetimi, davranışsal uyum ve travma bakım zincirini bütünleyen hedefli politika paketlerinin gerekliliğini ortaya koymaktadır.

Keywords

• Trafik kazaları
• halk sağlığı
• kesintili zaman serisi (ITS)
• karşı-olgusal analiz
• olgu-ölüm oranı (CFR)

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