Cars accidents and academic test results. The case of Medellín, Colombia

Medellin offers an interest case to study the effects of air pollution on academic performance at local scale. With 2.4 million people and an area of 382 km2, Medellin is the second largest city in Colombia2 and one of the most densely populated cities in Latin America. In the last 10 years, the city has experienced an accelerated growth in the number of vehicles and land
developments which, together with the geographical and weather conditions of the city, make Medellin one of the most polluted cities in the continent. According to the 2020 Quality of Life Report of Medellin Como Vamos (Meneses et al., 2020) in Medell ́ın and its metropolitan area, the annual PM10 concentrations range between 34 and 50 mg/m3, levels way above of the 20 mg/m3 level recommended by the WHO (2017). Similarly, annual averages of PM 2.5 concentrations range between 19 and 51 mg/m3, surpassing the WHO guidelines target of a maximum of 10 mg/m3. Additionally, the air quality index for PM2.5 in the center of the city was classified as good for 0% of all days in 2019 and only 2% in 2018.

In response to these circumstances, the Comprehensive Air Quality Management Plan for the AMVA (2017-2030) was designed as an institutional framework to mitigate the problem of air pollution. Given how vehicle emissions can account for up to 85% of all air pollution for big cities like Medell ́ın (CONPES, 2018), the strategies proposed include abandoning highly polluting modes of transportation by adopting cleaner technologies, encouraging the use of mas- sive transport systems and promoting active mobility in the city. No particular guideline was emitted regarding traffic accidents, despite the high accident rate in the city and its influence in the mobility.

In Colombia, and particularly in Medell ́ın, car accidents can be considered a major source of gas emissions. The number of motorcycles and reckless drivers make traffic accidents highly frequent, originating traffic congestion and pollution. Importantly, the particularities of car insurance requirements in the country make the congestion consequences of traffic accidents much worse. According to current legislation, only the Seguro Obligatorio de Accidentes de Tr ́ansito (SOAT) is mandatory for all vehicles. The SOAT covers all health expenses in the event of injuries like ambulance services, emergency care, hospitalization, medical treatments and even sick leave, for those involved in the accident. However, the SOAT does not cover the physical damages of vehicles involved in the accident and full coverage insurance is not required by law, leaving it up to the car owners to obtain it. This means that any type of vehicle accident can affect mobility for long periods of time. When a car crash occurs, it is common for drivers to remain at the collision point without moving their vehicles, waiting either for a negotiation on who pays for damages (specially if one or both of them don’t have full insurance) or for traffic police to determine whose responsible, issue an infraction and a court appointment to dispute responsibilities and costs. Given this idiosyncrasy, it is highly likely that a vehicle accident will cause time delays, traffic jams, slower speeds and overall, lots of concentrated air emissions, even if there is no injured people involved in. 3 This peculiarity makes car accidents within cities in Colombia a good variable to measure, and partially explain, levels of mobile source air pollution.