O2019: The Association Between County Ordinances Allowing Off-road Vehicles on Public Roads and Crash Rates

Background: Off-road vehicles (ORVs) account for over 700 deaths and more than 100,000 emergency department visits annually – of which children < 16 years account for 13% and 27%, respectively, in recent years. ORVs include all-terrain vehicles (ATVs) and side-by-side vehicles which are often generally referred to as utility task vehicles (UTVs). Legislative bodies across the country have increasingly allowed ATVs/UTVs on public roads, an environment for which they are not designed. In 2009, the Iowa state legislature gave individual counties the discretion to pass ordinances allowing ATVs/UTVs on roadways. This study investigates whether such ordinances are associated with increases in ORV crash rates, especially on public roads.

Methods: A statewide ORV crash database including records from the Iowa Department of Transportation (DOT), Department of Natural Resources (DNR) and State Trauma Registry (STR) from 2002-2018 was used for the study (3,426 unique crashes with 3,068 ATV crashes and 222 UTV crashes). Crashes for which county location could not be determined were excluded. Investigators compiled an ATV/UTV roadway ordinance database for all 99 Iowa counties. Using a zero-inflated time count series, correcting for background crash frequency trends and population, investigators compared the relative rates of crashes after ordinance passage to timepoints before ordinance implementation and to counties without such ordinances. Sub-analyses focused on more recent years (2008-2018) were also performed.

Results: Forty-nine county ORV ordinances went into effect by 2018 (72 of Iowa’s 99 counties by 2021). 2,347 crashes (69%) met inclusion criteria. Adjusted for year, there was a nearly 40% greater ORV crash rate in counties after passing an ORV roadway ordinance as compared to counties without ordinances (incidence rate ratio (IRR) 1.38, 95% CI 1.16-1.65). Roadway crashes (n=917) were more than 1/3 higher after ordinance passage (IRR 1.34, 95% CI 1.04-1.74). This roadway crash association remained statistically significant when analysis was limited to the years 2008-2018 (IRR 1.33, CI 1.02-1.74, n=627); to ATV crashes only (IRR 1.30, CI 1.10-1.53, n=734); and to ATV crashes excluding counties with UTV-only ordinances (IRR 1.44, CI 1.20-1.73, n=687). Comparative analyses limited to off-road crashes were not significantly different.

Conclusion: ORV crashes , especially those on roads, increased significantly after implementation of county ordinances allowing ATVs/UTVs on public roadways and when compared to counties without such ordinances. There were many roadway ORV crashes noted both before county ordinance passage and in counties where usage remained illegal suggesting inadequate enforcement of ORV roadway restrictions. Despite this, our study demonstrated that passage of laws allowing and expanding ATV/UTV access to public roads increases the number of crashes, likely leading to more deaths and injuries including among youth. Results from this study may help inform policymakers as they consider legislation regarding ATV/UTV usage on public roads.