Road User Behavior

Course Announcement: Spring 2023 Traffic Safety and Injury Control

November 14, 2022

People walking in crosswalk with traffic passing with course title, time and date overlaid

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Course Description:

Injuries from traffic crashes are a major cause of death and disability in the United States and around the world....

New Release: 2022 SafeTREC Traffic Safety Fact Sheets

September 12, 2022
2022 SafeTREC Traffic Safety Fact Sheets feature recent data on some of California's most pressing traffic safety issues to help inform future road safety efforts

UC Berkeley SafeTREC is excited to announce the release of the 2022 series of Traffic Safety Fact Sheets, which feature traffic safety data and trends at the national and state level on a variety of road safety topics. This series also highlights the Safe System approach to road safety, which the United States Department of Transportation...

2022 SafeTREC Traffic Safety Fact Sheet: Drug-Involved Driving

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
The use of cannabis, prescription drugs, and other drugs are increasingly prominent on roadways in the United States, where 25.3 percent of the nation’s 38,824 fatalities in 2020 were related to drug-involved driving. Driving can be impaired by a variety of legal and illegal drugs, substances, and medications. The effect of specific drugs on behavior and driving skills vary considerably depending on how they act in the brain and are metabolized. They can slow reaction time, decrease coordination, increase aggressive and reckless driving, impair cognitive function, or cause drowsiness. All of...

2022 SafeTREC Traffic Safety Fact Sheet: Motorcycle Safety

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022

Crashes involving motorcycles are a major traffic safety concern in the United States. Since motorcyclists are susceptible to injury during crashes, they comprise a disproportionate share of all injured and killed vehicle occupants. In 2020, motorcyclists comprised 14.4 percent of all traffic deaths in the US.

The primary countermeasures used to address this problem include motorcycle helmet laws and other helmet-oriented programs, rider training and licensing programs, vehicle enhancements, including anti-lock braking technology, rider conspicuity programs, campaigns to increase...

2022 SafeTREC Traffic Safety Fact Sheet: Speed-Related Crashes

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
A speeding-related crash is defined as one where a driver is speeding, racing, driving too fast for the conditions, or driving in excess of the posted speed limit. In the United States, in 2020, over one in four (29.0 percent) fatalities involved speeding, a rate that increased after plateauing in the late 2010s, following a decline earlier in the decade. Speeding reduces a driver’s ability to steer safely around curves or objects, reduces the amount of time a driver has to react to a dangerous situation, and extends safe stopping distances. Analyses presented in the police traffic services...

2022 SafeTREC Traffic Safety Fact Sheet: Occupant Protection

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
Restraint devices such as seat belts are a key element of motor vehicle occupant protection systems. Each year, NHTSA conducts the National Occupant Protection Use Survey (NOPUS) that measures, among many variables, the daytime use of seat belts by occupants age eight and older. The 2020 NOPUS reported that seat belt use was 90.3 percent among front-seat passengers, a slight decrease from the 90.7 percent observed in 2018. This change, along with the changes in subsets such as time of day or day of the week, was not statistically significant.

The United States Department of...

2022 SafeTREC Traffic Safety Fact Sheet: Pedestrian Safety

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
Everyone is a pedestrian, whether or not walking is one’s primary mode of travel. As a commute mode, walking is gaining in numbers. In 2020, pedestrian deaths accounted for 16.8 percent of all crash fatalities and nearly one-quarter (24.3 percent) of pedestrian fatalities involved a hit-and-run crash. From 2011 to 2020, pedestrian fatalities increased 46.2 percent while other traffic deaths only increased by 14.4 percent. From 2019 to 2020, pedestrian fatalities increased 3.9 percent, despite a 13.2 percent reduction in driving. Compared with all other racial categories, American Indian/...

2022 SafeTREC Traffic Safety Fact Sheet: Distracted Driving

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
The National Highway Traffic Safety Administration (NHTSA) defines distracted driving as activities that divert attention away from safe driving. This may include talking on the phone, texting, eating or drinking, manipulating audio systems, etc. According to the National Safety Council, cell phones remain a top distraction because of the length of time they are used by drivers on a daily basis.

The United States Department of Transportation uses the Safe System Approach to work towards zero roadway fatalities and serious injuries. The Safe System Approach recognizes that people...

2022 SafeTREC Traffic Safety Fact Sheet: Alcohol-Impaired Driving

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
While alcohol-impaired driving fatalities have fallen significantly in the last three decades, NHTSA reports that alcohol-impaired driving still comprises a large percentage of traffic injuries and fatalities. On average in 2020, someone died from an alcohol-impaired driving crash every 45 minutes. There was an increase in the number of alcohol-impaired driving fatalities and rate per 100 million Vehicle Miles Traveled (VMT) in the United States between 2019 and 2020.

The United States Department of Transportation uses the Safe System Approach to work towards zero roadway...

2022 SafeTREC Traffic Safety Fact Sheet: Aging Road Users

Katherine L. Chen
Bor-Wen Tsai
Garrett Fortin
Jill F. Cooper
2022
The older adult population in the United States aged 65 and older is expected to almost double between 2016 and 2060, from 49 million to 95 million. In 2020, there were 6,549 people aged 65 and older killed in traffic crashes in the United States; this accounted for 16.9 percent of all traffic fatalities. Older drivers 65 and older involved in fatal crashes decreased by 9.8 percent between 2019 and 2020.

As drivers age, physical and mental changes including reduced visual acuity, increased fragility, restricted movement, and cognitive impairment may directly and indirectly result in...