Lower volumes, higher speeds: Changes to crash type, timing, and severity on urban roads from COVID-19 stay-at-home policies

New publication: Stiles, J., Kar, A., Lee, J. and Miller, H.J. (2021) “Lower volumes, higher speeds: Changes to crash type, timing, and severity on urban roads from COVID-19 stay-at-home policies,” Transportation Research Record (online first)

Abstract: Stay-at-home policies in response to COVID-19 transformed high-volume arterials and highways into lower-volume roads, and reduced congestion during peak travel times. To learn from the effects of this transformation on traffic safety, an analysis of crash data in Ohio’s Franklin County, U.S., from February to May 2020 is presented, augmented by speed and network data. Crash characteristics such as type and time of day are analyzed during a period of stay-at-home guidelines, and two models are estimated: (i) a multinomial logistic regression that relates daily volume to crash severity; and (ii) a Bayesian hierarchical logistic regression model that relates increases in average road speeds to increased severity and the likelihood of a crash being fatal. The findings confirm that lower volumes are associated with higher severity. The opportunity of the pandemic response is taken to explore the mechanisms of this effect. It is shown that higher speeds were associated with more severe crashes, a lower proportion of crashes were observed during morning peaks, and there was a reduction in types of crashes that occur in congestion. It is also noted that there was an increase in the proportion of crashes related to intoxication and speeding. The importance of the findings lay in the risk to essential workers who were required to use the road system while others could telework from home. Possibilities of similar shocks to travel demand in the future, and that traffic volumes may not recover to previous levels, are discussed, and policies are recommended that could reduce the risk of incapacitating and fatal crashes for continuing road users.

Keywords: Road safety, COVID-19, crash severity, traffic speed, transportation planning

Evidence of Increased Vehicle Speeding in Ohio’s Major Cities during the COVID-19 Pandemic

New paper:   Lee, J., Porr, A. and Miller, H.J. (2020) “Evidence of increased vehicle speeding in Ohio’s major cities during the COVID-19 pandemic,” Transportation Findings, June. https://doi.org/10.32866/001c.12988

Abstract.  This paper compares the speeding patterns before and after the COVID-19 pandemic in three major cities in Ohio, USA: Columbus, Cincinnati, and Cleveland. Using high-resolution and real-time INRIX traffic data, we find evidence of increased speeding in all three cities. In particular, we observe an increase in the spatial extent of speeding as well as in the average level of speeding. We also find the mean differences in speeding before and after the COVID-19 outbreak are statistically significant within the study areas.

Traffic and Speeding During The Pandemic – The Sound of Ideas – WCPN (Cleveland Public Radio)

On May 18th,I was a guest on the WCPN Cleveland Public Radio show the Sound of Ideas.  We talk about the evidence of increased speeding in Ohio during the COVID-19 pandemic, and more broadly about the current opportunity to rethink how we use street space in our cities:

WCPN (Cleveland) – The Sound of Ideas: Traffic and Speeding During The Pandemic