# How Crash-Test Dummies And Biomechanics Improve Vehicle Safety > Last updated: 2025-10-27 [Car accidents](/harrisburg-car-accident-lawyer/) involve complicated physics and biomechanics. Physics is the science of forces and motion, while biomechanics explains the body’s structure and movement. Together, these fields of study tell scientists how crashes affect vehicle occupants and the injuries that can result from them. Crash-test dummies are an important tool for gathering data for this analysis. These devices simulate the human body to demonstrate how crashes affect vehicle occupants. This information, in turn, can be used to improve vehicle-safety systems, traffic laws, and driver-education programs. ## How Crash-Test Dummies Work Crash-test dummies have two main characteristics. Dummies are designed to replicate the human body’s structure and movement, and they are equipped with sensors to gather crucial data during impact. ### Crash-Test Construction First, they’re constructed to mimic the basic structure of the human body. This means they have roughly the same proportions and weight as a living person. Moreover, their joints typically allow them to move in a way that simulates the motion of a human subjected to the same forces. Testers use a [range of sizes](https://www.nhtsa.gov/nhtsas-crash-test-dummies) to represent a variety of age and sex combinations. While scientists need to understand what a person of average height and weight may experience, they must also determine what can happen to occupants at the extremes. Testers use dummies that represent the [5th, 50th, and 95th percentiles](https://www.caranddriver.com/features/a28510766/crash-test-dummies-how-they-work/) in height and weight for each sex. This testing regimen has proven successful. For example, studies have shown that airbags are generally safe for people of average height. However, children and small adults tend to sit so close to the dashboard or steering wheel that the airbag can strike them while deploying, causing their heads to whip backward forcefully. The resulting [airbag injury](/harrisburg-car-accident-lawyer/airbag-injuries/) can be fatal. ### Sensors in Crash-Test Dummies Second, crash-test dummies contain sensors that can measure force, strain, and acceleration or deceleration. The data from these sensors tells researchers what a human body would experience in the same circumstances. Centuries of observation and testing have told scientists what the body can withstand. Researchers use the data from crash-test dummies to estimate the possible effects of different crash scenarios. Scientists also inspect the dummies for physical damage that indicates the injuries a person would suffer. For instance, a bent frame in the dummy’s leg would suggest that a human in the same situation might have suffered a leg fracture. ## Countermeasures from Crash-Test Data Crash testing has provided valuable insight into what happens biomechanically during an auto accident. Using these insights, engineers develop countermeasures to improve vehicle safety. The following devices and systems have resulted from crash testing. ### Crumple Zones Modern cars typically eschew solid steel in the front and rear of the vehicle. Instead, they use plastic bumpers and thin fenders that deform on impact. These “crumple zones” absorb the crash energy so that the vehicle occupants experience less violent movement in a head-on or [rear-end crash](/harrisburg-car-accident-lawyer/rear-end/). ### Airbags Airbags deploy rapidly when a vehicle is struck to form a cushion for the front-seat occupants before they whip forward. Crash testing helped engineers determine how quickly the devices must deploy. Testing also helped work out how quickly they must deflate once the occupant impacts them so the person’s head is caught and slowed at a safe rate. ### Seat Belt Laws Seat belts have existed for decades. Crash testing measured the benefits of seat belts compared to their potential for injuries. As a result, 49 states [require seat belt use](https://www.ghsa.org/state-laws-issues/seat-belt-use) for front-seat occupants, and many require all passengers to wear them. ## Contact Marzzacco Injury Law Today to Schedule a Free Consultation With a Harrisburg Car Accident Attorney Measures like seat belts and airbags can only do so much on their own. Car accidents are highly energetic events that can cause serious or even fatal injuries despite the relative safety of the vehicles involved. Testing safety equipment is just one of many pieces of the puzzle when it comes to reducing crash injuries and deaths. If you were injured in a car accident in Harrisburg, [Marzzacco Injury Law](/about-our-firm/) can help guide you through the aftermath. Call us today to schedule your [free consultation](/contact-us/) with a Harrisburg car accident lawyer.