Temperature and Leniency: Man vs Machine

Speaker: A/Prof Romain Gauriot

Affiliation: Deakin University

Location: Room 102, Chamberlain Building (#35), St Lucia Campus

Zoom: https://uqz.zoom.us/j/82603079317

Abstract: We use over 7 million speeding fines from Queensland, Australia, to study how outdoor temperature affects police officer discretion. We compare police-issued fines with those issued by automated speed cameras, which detect violations without exercising discretion, allowing us to separate changes in officer behaviour from temperature-driven changes in driver behaviour. Officers are 3.5 times more likely than mobile cameras to issue a fine 1 km/h below a penalty threshold, indicating substantial leniency. Although the share of lenient police fines declines with temperature, this relationship is entirely explained by geography: Queensland’s hottest areas are also its least lenient, and their fixed differences in leniency reproduce the entire observed relationship between temperature and leniency. Conditional on location, temperature has no effect on officer discretion. We also find no evidence that officers change where they enforce on hot days: police fine counts respond to temperature similarly to those from fixed cameras, which cannot relocate. By contrast, the same design detects a sharp decline in police enforcement on rainy days, suggesting that the temperature null does not reflect a lack of statistical power.