When the arrival of the COVID-19 pandemic put the brakes on much of our daily travel, traffic engineers wondered if the decrease in vehicle volumes would lead to a significant decrease in traffic crashes, injuries and fatalities on the highways. Instead, traffic fatalities increased nationwide in 2020, a trend that continued in many states in 2021. As crash data from 2020 and 2021 become available, researchers are looking for possible explanations for the unexpected increases. One prominent theory has been an increase in driving speed.
New numbers cited by the National Highway Traffic Safety Administration (NHTSA) estimate that 38,680 people died in motor vehicle crashes in 2020 — an increase of 7.2% from the previous year — despite a 13% decrease in total vehicle miles traveled. This equates to a 23% increase in fatality rate — the number of fatalities per million vehicle miles driven — and was the highest number of traffic fatalities reported since 2007. From January through September 2021, an estimated 31,720 people died in traffic crashes, representing an increase of approximately 12% from the same period in 2020. As traffic volumes rebounded to near pre-pandemic levels in 2021, the increased fatality rate from 2020 remained nearly unchanged.
Early analysis of the 2020 data showed increases in occupant ejection and unrestrained occupants, single-vehicle crashes, alcohol involvement crashes, weekend and nighttime crashes and speeding-related crashes. These findings may indicate a pandemic-driven shift in travel patterns and purposes. Rather than congestion-related multi-vehicle crashes during the morning and evening commutes, which tend to be less severe, crashes occurred more frequently at night and on weekends, often involving a single vehicle leaving the roadway at a high rate of speed. These crash types, especially when drivers are unrestrained, are much more likely to be deadly.
In 2019, the Kansas Highway Patrol issued 1,758 tickets for excessive speeding — over 100 mph. That number increased 60% to 2,823 tickets in 2020 and another 17% to 3,309 in 2021. In Missouri, excessive speeding citations issued by the Missouri Highway Patrol jumped from 1,628 in 2019 to over 2,600 in each of the next two years, also an increase of about 60%. A 2021 speed study conducted in several locations along the Kansas Turnpike showed an increase in the 85th percentile speeds of 5 to 10 mph compared to a previous speed study in 2011.
Every crash is a unique situation with a variety of factors influencing the outcome, but it’s a fact that as speeds increase, the energy transferred in a crash also increases — making them more severe. Research from 2004 shows that an increase of only 5% in average speed can increase fatalities by nearly 20% and injuries by 8%. Increases in speed are especially significant with respect to collisions with vulnerable road users such as pedestrians and cyclists.
Safety advocates are working to understand root causes of why speeds have increased and how to reverse the trend. The pandemic impacted lives in a number of ways that may have influenced how individuals drive. When shifting traffic patterns reduced the number of vehicles on the road, there were not as many cars present to influence driving speed. At the same time, many people have experienced higher levels of mental distraction as a result of the pandemic, beyond the ever-present distraction from electronic devices.
As mental health challenges increased, alcohol and drug use did as well. One study found that alcohol sales increased 54% at the start of the lockdown in March 2020 compared with the same week the previous year, and that online alcohol sales increased over 250%. The Centers for Disease Control and Prevention recorded 100,306 fatal drug overdoses for the 12 months ending in April 2021 — an increase of 28.5% from the year before. In addition, more of those involved in fatal car crashes were not buckled up, adding to the evidence of increased risk-taking on the highways. All these factors together have resulted in crashes with higher impact energy, drivers that are more distracted with reduced ability to perceive and react to hazards, and a greater risk of ejection from the vehicle upon impact, all factors that make crashes more deadly.
In some locations, law enforcement activities decreased, often as a result of pandemic-related staffing shortages. The perception that officers are not waiting around the corner to catch speeding and other illegal and unsafe driving behaviors, whether accurate or not, may also play a role in the risks people are willing to take when driving.
While the hope that traffic fatalities and the fatality rate will begin to fall as the world begins to return to normal, there are several things that can be done by transportation professionals, decision-makers and roadway users to help turn the tide. First, automated speed enforcement cameras can encourage drivers to stay near the posted speed limit, while reducing safety concerns for officers and providing widespread, consistent, and equitable enforcement over time. Second, road designers should consider using features of self-enforcing roads to provide more contextual clues about the proper speed to be driven in a given location. Features that can lower speeds include narrow lanes, the presence of bike lanes, roadside and median landscaping, marked crosswalks and gateway designs. In some cases, a little congestion can go a long way toward controlling average speeds and reducing the most severe crashes, so it doesn’t need to be avoided at all costs.
In the longer term, more research is needed on how speed characteristics influence the likelihood and severity of crashes. Our current prediction models all assume that crashes increase when traffic volumes increase. Recent experience has taught us that is not always the case. The models should account for speed variables to more thoroughly explain the safety benefit that can be realized when speeds are reduced.
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