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Read moreHarsh braking and acceleration are aggressive driving behaviors that hurt fleets in big ways: They increase accident risk, strain vehicle systems and drive up fuel and maintenance costs.
But fleet managers can help drivers reduce or eliminate these behaviors with the right tools.
Monitoring harsh driving behaviors like these help fleet managers identify unsafe driving patterns early, coach drivers more effectively and reduce unnecessary wear on critical components such as brakes, tires, engines and transmissions.
Over time, addressing harsh driving supports safer roads, more reliable vehicles and helps companies save money and mitigate accidents or injuries making monitoring harsh braking and acceleration an essential part of any comprehensive fleet safety and training program.
What is harsh driving?
Harsh driving, sometimes called hard driving, is a pattern of driving behaviors that includes hard braking, hard acceleration, speeding and hard cornering. These actions often occur together and reflect a driving style that prioritizes speed or urgency over smooth, controlled operation. Collectively, this behavior is commonly referred to as “lead foot syndrome,” a shorthand for drivers who accelerate quickly, brake abruptly, speed, follow too closely and push vehicles beyond standard use.
What is hard braking?
Hard braking occurs when a driver applies excessive or abrupt force to the brake pedal, causing the vehicle to decelerate more quickly than normal driving conditions require. In many cases, harsh braking is a sign that a driver is following traffic too closely, reacting late to changing conditions or failing to anticipate stops ahead.
Common examples of hard braking include:
- Slamming on the brakes to avoid a rear-end collision
- Sudden stops at traffic lights or intersections
- Abrupt braking in congested traffic
From a safety perspective, hard braking increases the risk of rear-end collisions and loss of vehicle stability, particularly for heavier vehicles. Repeated hard braking also accelerates brake wear, increases heat buildup and can reduce the overall effectiveness of the braking system over time.
What is hard acceleration?
Hard acceleration occurs when a driver applies excessive force to the accelerator, causing the vehicle to increase speed rapidly. This behavior is often associated with aggressive starts, frequent speeding or unnecessary throttle input.
Examples of hard acceleration include:
- Rapid acceleration from a stop
- Sudden changes in speed, especially when passing or merging
- Repeated surges in speed during normal driving
Hard acceleration places additional stress on the engine, transmission and drivetrain while also reducing fuel efficiency. When repeated consistently, it can indicate risky driving habits that increase both safety risk and operating costs.
When harsh braking and acceleration does not indicate unsafe driving
It’s important to recognize that not every harsh braking and acceleration event reflects poor driving behavior. In some cases, these events may occur during crash avoidance or emergency situations.
Some GPS tracking systems also use Automatic Crash Notification (ACN), which relies on very high deceleration thresholds to detect potential collisions and automatically alert emergency services. For this reason, harsh braking and acceleration events should always be evaluated in context rather than treated as automatic indicators of unsafe driving.
How does harsh braking and acceleration impact fleet safety?
Repeated harsh braking and acceleration increases safety risk for drivers and others on the road. These behaviors reduce vehicle control and increase the likelihood of collisions, especially in high-traffic or unpredictable driving environments.
Safety impacts of harsh braking and acceleration as well as hard cornering can include:
- Reduced control and longer stopping distances
- Increased risk of rear-end collisions
- Greater likelihood of jackknifing, where a truck's trailer swings out at a sharp angle, forming an "L" or "V" shape, or rollover crashes
- Excessive heat and wear on braking systems
- Unnecessary activation and strain on anti-lock braking system components
When vehicles operate with fewer safety margins, small mistakes or delayed reactions can escalate quickly into serious incidents. Hard braking, improper braking and inappropriate speed were among the most prevalent risky behaviors associated with crashes and near-crashes in a National Highway Traffic Safety Administration study.1
Fleet safety is an investment that should never be undervalued. It’s not just part of a company's responsibility to its staff, but also part of its corporate responsibility to the general public. Advancements in technology now make it economical and easy for fleet managers to detect harsh driving behaviors, effectively coach drivers and implement safety programs around safe driving standards.
Download this free infographic to learn 3 ways dashcams boost driver safety.
How does harsh braking or acceleration impact fuel costs and maintenance?
While harsh driving affects safety, it also has a direct impact on a fleet’s bottom line. If you’ve ever wondered, "Does harsh braking use more fuel?" The answer is that it does: Aggressive driving can reduce fuel economy by 15-30% at highway speeds and 10-40% in stop-and-go traffic.2
Harsh driving does more than waste fuel, it places extreme stress on vehicle components as well. Repeated harsh braking or acceleration can damage the transmission by creating sudden, jarring spikes in momentum and temperature that accelerate wear on internal parts like clutches, bands and gears. This also breaks down transmission fluid, reducing lubrication and forcing components to grind.
Hard braking can also overheat brake pads, leading to brake glazing, where the brakes are too smooth to grip effectively.
Over time, hard braking can also strain the anti-lock braking system by forcing its components to engage more often than necessary, increasing wear and tear on sensors and hydraulic parts designed for emergency use, not everyday driving.
For fleets, that means harsh braking and acceleration as well as hard cornering can lead to:
- Lower fuel efficiency and higher fuel spend
- Increased brake replacement and maintenance frequency
- Accelerated tire wear reducing tire lifespan
- Increased risk of accidents from the breakdown of engines and transmissions
- More downtime for repairs
Reducing harsh driving behaviors helps fleets extend vehicle lifespan, improve fuel economy and better control maintenance costs.
How is harsh braking and acceleration detected?
Harsh braking and acceleration are detected through accelerometers, which are included in most GPS tracking devices. These accelerometers measure movement and its intensity in a specific direction. A piezoelectric accelerometer, which uses a suspended mass inside a fixed container, is one of the most common. As the container is moved, the mass moves in the opposite direction, putting pressure on the quartz crystal, which in turn converts that pressure into an electric signal. The greater the force, the greater the electrical current.
Depending on how it is being used, an accelerometer has different levels of sensitivity, suited to its application, whether in a smartphone or inside a motor vehicle. The electrical current it generates is used to trigger a report that can be interpreted by telematics software, as well as near real-time alerts to the driver.
Different telematics systems set different thresholds that trigger an event. Verizon Connect uses these thresholds to trigger a hard braking or hard acceleration event:
- Hard acceleration: The vehicle speeds up suddenly by more than 5 mph per second or when the G-force on the accelerometer exceeds 0.220g for at least one second.
- Hard braking: The vehicle slows down suddenly by more than 6 mph per second, or when the G-force is above 0.265g for at least one second.
- Hard cornering: The vehicle makes a harsh turn at speed, achieving a G-force above 0.4g for at least two seconds.
How fleet technology helps reduce harsh braking and acceleration
GPS vehicle tracking gives fleet managers a clear view of the driving styles of all employees, whether they are meeting and exceeding safety expectations or need additional coaching to get there.
These systems monitor speed, idle times, harsh braking and fuel usage across all vehicles and all drivers, giving managers actionable data to help employees improve. Managers can run reports on each individual vehicle or each driver or calculate fuel cost for the whole fleet in a month, or how much fuel one driver uses versus another for the same number of miles driven.
Additionally, using video, including AI-powered dashcams, can add valuable context by showing what happened before, during and after harsh driving events. Reviewing these clips with drivers can also add important evidence and direction to coaching sessions, helping drivers better understand their behaviors, recognize risky patterns and make adjustments.
Practical driving habits that reduce harsh braking and acceleration
Technology plays an important role, but day-to-day driving habits also make a difference. Encouraging smoother driving techniques can help drivers reduce harsh driving events and operate more safely. Practical habits include:
- Anticipate traffic conditions ahead to avoid sudden stops. A good rule of thumb is to maintain a 15-second lead time. This means looking ahead at the distance you will travel in approximately 15 seconds to anticipate traffic signals, slowdowns and stops.
- Maintain a safe following distance of about three seconds to allow gradual braking.
- Make smooth transitions between accelerating and braking by using the “pivoting foot technique.” Keep your heel on the floor at all times and pivot the rest of your foot between the accelerator and the brake for more controlled pressure on the pedals. This also helps avoid “stomp” braking.
- Ease off the throttle gradually instead of accelerating aggressively.
- Slow down significantly before taking a turn and maintain a consistent, gentle speed. Focus on the exit, not the turn itself, and gently accelerate after the apex.
These techniques can not only halt harsh braking to improve fleet safety but also support better fuel efficiency and vehicle longevity.
Want to hear how using fleet tracking technology can help you prioritize safety across your fleet? Schedule a demo with one of our experts.