NEW YORK (AP) — Road deaths are declining in the U.S. and worldwide, but lower-income countries aren't experiencing much of the improvement, according to a study published Monday.

Global rates of road injuries and deaths each fell more than 30% between 1990 and 2023, according to the study published in Lancet Public Health, which noted the progress varied from country to country.

Pedestrian and vehicle occupant deaths rose over that time in six countries — including the United States. However, more recent data shows road deaths fell in the U.S. in 2024 and 2025.

The World Health Organization put out its own numbers Monday, finding that road traffic deaths declined by 21% between 2011 and 2025. However, traffic crashes still claimed more than 1.1 million lives last year, and they remain the leading cause of death among children and youth aged 5 to 29 years, the WHO said.

Road deaths involve fatal injuries that happen to pedestrians, cyclists and people riding in cars, trucks and other vehicles. Complete data is lacking in some countries, so the researchers behind the new report made estimates based on what data is available.

The researchers, from the University of Washington’s Institute for Health Metrics and Evaluation, found that road injury rates are higher in high-income countries, but 90% of road deaths occur in low-income countries.

In many low-income countries, safety measures have not kept up with rapid growth in cities and use of motorized vehicles. For example, seat belt mandates are more common in high-income countries, as are car safety features such as air bags.

“Road injury outcomes are shaped not only by crashes, but by the systems designed to prevent them and protect people when they occur,” said Liane Ong, the new paper's senior author, in a statement.

However, there have been conflicting trends in the U.S., including the proliferation of taller and larger passenger vehicles, the authors wrote. U.S. officials also have said thousands of deaths each year can be attributed to “distracted driving," including drivers looking at their phones.

In the U.S., motor vehicle traffic fatalities rose in the last decade and peaked at more than 43,000 in 2021 before beginning to decline, according to the National Highway Traffic Safety Administration. The agency estimated the count fell to about 36,600 last year.

Meanwhile, the Governors Highway Safety Association recently reported that U.S. drivers hit and killed 7% fewer people walking on U.S. roads in 2025 compared with the year before. It was the largest annual reduction since pedestrian deaths began falling three years ago, but it was still higher than what the numbers were before the COVID-19 pandemic.

The WHO identified road safety as an international public health priority more than two decades ago. The Lancet report's release coincides with the start of a two-day United Nations high-level meeting on improving global road safety, being held in New York City.