SUVs and pedestrian safety

Syu-Yu Wang

Leeds Institute for Transport Studies, University of Leeds, UK

Caroline Tait

Leeds Institute for Transport Studies, University of Leeds, UK

Eugeni Vidal-Tortosa

Department of Geography, Autonomous University of Barcelona, Spain

Roger Beecham

School of Geography, University of Leeds, UK

Steve O’Hern

Leeds Institute for Transport Studies, University of Leeds, UK

Robin Lovelace

Leeds Institute for Transport Studies, University of Leeds, UK

Background

Definitions of SUVs

  • KIA (2019): “SUV stands for Sports Utility Vehicle, a car similar to a minivan or a station wagon, but with a much tougher look and a design suited for off-road driving.”
  • Lexus (2019): “SUV stands for Sports Utility Vehicle, a fairly loose term but one that generally refers to stylish, sleek looking vehicles that offer elegant city driving but also handle rugged terrain thanks to a typical 4x4 capability.”
  • Mitsubishi (2019): “SUV stands for sport utility vehicle, a term generally applied to automobiles that combine the features of a passenger car, like plenty of passenger and cargo space, with aspects of an off-road vehicle.”
  • AutoTrader (2021): “SUV is automotive jargon that stands for Sports Utility Vehicle. It refers to a type of car that sits high up, off the ground, and often has four-wheel drive and sturdy styling.”

SUV models

8 out of the top 10 best selling models were SUVs in 2024 (SMMT)

SUV policies

  • Policies to discourage large vehicles are emerging due to safety and environmental concerns.
  • Paris: Voted to triple parking fees for vehicles over 1,600 kg (2,000 kg for electric), costing up to €18/hour in the city center (European Commission 2024).
  • UK: Considering a “weight malus” or surcharge on the vehicle excise duty (VED) for heavier new cars, similar to a policy in France (Palmer 2024; Rodger 2024).

Reforming UK car taxation

Source: www.transportenvironment.org(Palmer 2024)

Methods

  • Data from STATS19 database on traffic casualties in Great Britain (2005-2022).
  • 239 unique SUV models identified.
  • Multinomial logit model used to explore the relationship between risk factors and injury severity.
  • Outcomes: Fatal, Serious, or Slight injury.

Results

Figure 1: Year-on-year pedestrian crash counts by vehicle type and severity (2005-2022).

Model and headline results

The probability of a particular crash \(n\) resulting in a specific severity outcome \(i\) is given by the following multinomial logit model:

\[ P_n(i) = \frac{\exp(\beta_i X_{in})}{\sum_{\forall I} \exp(\beta_I X_{In})} \]

Relative Risk Ratios (RRR), relative to baseline outcome (slight), are calculated as \(RRR = exp(X\beta_i)\).

  • Pedestrians hit by SUVs are more likely to be seriously injured (RRR = 1.126) or killed (RRR = 1.204) compared to those hit by non-SUVs.
  • Vehicle mass is also a significant predictor of injury severity.
  • SUV status is a better predictor than vehicle mass, width, or length alone.

Model results II

Limitations and Future Research

  • The binary SUV/non-SUV classification oversimplifies diversity of the vehicle fleet.
  • The STATS19 dataset lacks detailed vehicle design data, such as bumper height and front-end shape, which are likely key risk factors.
  • The study identifies increased risk but cannot fully explain the mechanisms (e.g., are SUV drivers more reckless, or is it purely vehicle design?).
  • Focus on severity says little about frequency of collisions nor impacts on active travel/stress/willingness to use active/public modes
  • Future work should investigate which specific vehicle characteristics are most dangerous, how vehicle characteristics and driver behaviour affect other modes, and explore the role of marketing and driver behavior

Discussion and Conclusions

  • The results imply SUVs are more dangerous for pedestrians in Great Britain, supporting findings from the USA.
  • Motivate policy debates on vehicle size and road safety (Singh 2024).
  • Supports measures like increased parking fees for large vehicles (European Commission 2024).
  • Further research is needed on specific vehicle characteristics like bumper height.

Vehicle type in perspective

Credit: Rifki Wijaya

Towards joined-up vehicle tax/incentives policy for public health?

Source: https://oodavid.com/

References

Axsen, Jonn, and Zoe Long. 2022. “Sport Utility Vehicles and Willingness-to-Downsize: A Mixed-Method Exploration of Functional, Symbolic, and Societal Consumer Perceptions in Canada.” Energy Research & Social Science 92 (October): 102776. https://doi.org/10.1016/j.erss.2022.102776.
Ballesteros, Michael F, Patricia C Dischinger, and Patricia Langenberg. 2004. “Pedestrian Injuries and Vehicle Type in Maryland, 19951999.” Accident Analysis & Prevention 36 (1): 73–81. https://doi.org/10.1016/s0001-4575(02)00129-x.
Dearman, Charles, James Milner, Glenn Stewart, Giovanni S. Leonardi, John Thornes, and Paul Wilkinson. 2023. “Sports Utility Vehicles: A Public Health Model of Their Climate and Air Pollution Impacts in the United Kingdom.” International Journal of Environmental Research and Public Health 20 (11): 6043. https://doi.org/10.3390/ijerph20116043.
European Commission. 2024. “Paris Introduces Triple Parking Fees for SUVs - European Commission.” https://urban-mobility-observatory.transport.ec.europa.eu/news-events/news/paris-introduces-triple-parking-fees-suvs-2024-02-12_en.
Henary, Basem Y., Jeff Crandall, Kavi Bhalla, Charles N. Mock, and Bahman S. Roudsari. 2003. “Child and Adult Pedestrian Impact: The Influence of Vehicle Type on Injury Severity.” Annual Proceedings / Association for the Advancement of Automotive Medicine 47: 105–26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217548/.
International Energy Agency. 2024. “SUVs Are Setting New Sales Records Each Year and so Are Their Emissions Analysis.” https://www.iea.org/commentaries/suvs-are-setting-new-sales-records-each-year-and-so-are-their-emissions.
Palmer, R. 2024. “Reforming UK Car Taxation.” https://www.transportenvironment.org/uploads/files/TE-briefing-UK-car-taxation-2024.pdf.
Paulozzi, L J. 2005. “United States Pedestrian Fatality Rates by Vehicle Type.” Injury Prevention 11 (4): 232–36. https://doi.org/10.1136/ip.2005.008284.
Rodger, J. 2024. “SUV Drivers Told They’ll Be ’Targeted’ Under New Car Tax Rules.” https://www.birminghammail.co.uk/news/midlands-news/suv-drivers-told-theyll-targeted-28748645.
Singh, Sarwant. 2024. “The Future Of SUVs: A Power-Packed Drive Into Tomorrow.” https://www.forbes.com/sites/sarwantsingh/2024/08/19/the-future-of-suvs-a-power-packed-drive-into-tomorrow/.
Transport & Environment. 2024. “UK SUV Sales Have Increased by More Than a Fifth in One Year.” https://www.transportenvironment.org/te-united-kingdom/articles/uk-suv-sales-have-increased-by-more-than-a-fifth-in-one-year.

Appendix: Reproducible research

Plug: try out the stats19 R package, endorsed by the UK Department for Transport, to access and analyse STATS19 data.

pkgs = c("tidyverse", "stats19")
pkgs_to_install = pkgs[!pkgs %in% installed.packages()[, "Package"]]
if(length(pkgs_to_install)) install.packages(pkgs_to_install)
library(tidyverse)
library(stats19)

Reproducing 2023 results

Source: gov.uk

In R:

cas_2023 = get_stats19(year = 2023, type = "cas")
table(cas_2023$casualty_severity)

  Fatal Serious  Slight 
   1624   26030  105323 

  Fatal Serious  Slight 
    715   12015   46471

Challenge: reproduce annual official statistical report on road safety

Plug: Data Science for Transport Planning Course

Source: search for “Data science for transport planning” online to find the course