NHTSA Data Bonus – Roadway Ownership Data Shows State Owned Roads Have Increasing Share Of Traffic Deaths

This is bonus part four in a series on new National Highway Traffic Safety Administration (NHTSA) data. Parts one, two, and three looked at driver-related, vehicle-related, and speed limit-related data elements. Roadway ownership data is not new in the NHTSA Fatality and Injury Reporting System Tool (FIRST), but it is worthy of being featured.

Roadway ownership data is only available since 2015, which limits its value for analysis over time. For pedestrian and bicyclist deaths, the trend of increased fatalities started around 2009. For general analysis, 5-year periods which are typically used on data.bikeleague.org cannot be used for comparison purposes because there are fewer than ten years of data.

Comparing the time periods 2015-2017 and 2019-2021 shows how recent increases in traffic deaths are primarily due to increased traffic deaths on state-owned roads. State-owned roads accounted for a plurality of traffic deaths for people biking, walking, and occupying vehicles in 2019-2021 and saw the highest increases in their share of traffic deaths relative to other roadway owners for all person types. In contrast, city and town-owned roads decreased their share of traffic deaths for all person types.

Looking at absolute figures instead of share also shows that the increase in traffic deaths is primarily due to increases in traffic deaths on state-owned roads. Between 2015-2017 and 2019-2021, the number of traffic deaths on city and town-owned roads decreased for all person types except occupants on city-owned roads.

Looking at bicyclist and pedestrian deaths on an annual basis, roads owned by state highway agencies appear to consistently increase over the period 2015-2021. Bicyclist and pedestrian deaths on city-owned roads were highest in 2016 and then fell and rose again to near those highs in 2021. County-owned roads and roads without reported ownership look mostly flat, with some variation and then a rise to 2021, when both bicyclist and pedestrian deaths reached multi-decade highs.

It is worth noting that four states account for over 90% of roads without reported ownership data. For bicyclist deaths without reported ownership data California accounts for 43%, Texas accounts for 30%, Florida accounts for 18%, and Michigan accounts for 6%. For pedestrian deaths without reported ownership data California accounts for 40%, Texas accounts for 40%, Florida accounts for 10%, and Michigan accounts for 5%. Of those four states, only Michigan has improved their reporting over time and Michigan has not had a pedestrian or bicyclist death without reported roadway ownership since 2017.

State-owned roads tend to be higher speed and higher volume, creating greater kinetic energy that can lead to death or serious injury in a crash. For the most part, the most common crash types indicated for bicyclist and pedestrian fatalities were similarly represented across roadway ownership types. This may indicate that it is the conditions of the road, not behaviors, that are leading to difference in outcomes. 

Over-represented crash types for people killed while walking included “crossing expressway” and “unusual circumstances,” which do not necessarily describe the behaviors of people walking beyond their interaction with a road not meant for their safety. 

The most over-represented crash type for people killed while biking was “Bicyclist Failed to Yield - Midblock” which may describe a person trying to cross the road, most often hit by a driver proceeding straight who also has the opportunity to yield.

In most places, state Departments of Transportation retain control over state-owned roads within cities, towns, and counties. The plans, policies, and efforts of state DOTs will be important for addressing the increase in traffic deaths in recent years, which has primarily occurred on state-owned roads.