Types of Truck Accidents in San Diego and Their Common Causes

The way a truck crash happens often tells you where to look for the evidence.

A rear-end collision may point to speed, following distance, and braking data. A rollover can raise questions about speed, cargo loading, and vehicle stability. An underride crash may require close examination of the trailer, its rear impact guard, and its lighting.

This guide explains the most common types of truck accidents in San Diego, what causes them, and the evidence that can help prove what happened. For an overview of our firm’s work in these cases, visit our San Diego truck accident attorney page.

Key Points

• The crash type helps identify the evidence. Speed data, electronic logs, maintenance records, cargo documents, and video answer different questions depending on how the collision occurred.
• Responsibility can extend beyond the driver. A motor carrier, cargo loader, maintenance company, freight broker, or manufacturer may share responsibility.
• Evidence should be preserved early. Electronic data can be overwritten, and trucks and failed parts can be repaired or returned to service soon after a crash.

Common Types of Truck Accidents

From 2014 through 2024, law enforcement reported 3,890 injury or fatal crashes involving large trucks in San Diego County. Rear-end collisions were the most common type, at 42.9 percent, followed by sideswipes at 22.1 percent and broadside collisions at 16.9 percent, according to our San Diego truck accident statistics. These figures include every reported crash involving a truck, no matter which driver was at fault. A rear-end crash, for example, may involve a truck striking another vehicle or another vehicle striking a truck.

The sections below cover these and other crash types that can cause serious injuries.

Rear-End Truck Collisions

A loaded commercial truck needs more time and distance to stop than a passenger vehicle under many driving conditions. Speeding, distraction, fatigue, following too closely, worn brakes, and delayed reaction can turn slowing traffic into a catastrophic rear-end crash.

California law prohibits a driver from following another vehicle more closely than is reasonable and prudent under the circumstances. See Vehicle Code section 21703.

What the case turns on: Electronic speed and braking data and video can show how fast the truck was traveling, when the driver braked, and how much distance was available. Hours-of-service records can help investigators assess whether fatigue may have contributed. When the driver claims the truck would not stop, the maintenance history becomes important.

Blind-Spot and Lane-Change Crashes

Commercial trucks have large areas around the tractor and trailer that may be difficult for the driver to see. These areas are commonly called blind spots or “no-zones.” A lane-change crash may occur when a truck driver fails to recognize a vehicle traveling alongside, changes lanes without enough clearance, merges improperly, or fails to keep a proper lookout.

Federal regulations generally require trucks and truck tractors to have rear-vision mirrors positioned to give the driver a view along both sides of the vehicle. See 49 C.F.R. section 393.80.

What the case turns on: Video, lane markings, and the positions of both vehicles before impact can show whether the other vehicle was visible and whether the truck had room to move over. The trucking company’s training and supervision may also become relevant.

The defense may argue that the smaller vehicle lingered in a blind spot or otherwise contributed to the collision, which makes California’s comparative-fault rules important. Our guide to liability in truck accidents explains how responsibility can be divided among multiple parties.

Broadside and Intersection Collisions

A broadside, or T-bone, collision occurs when the front of one vehicle strikes the side of another, usually at an intersection, driveway, or freeway ramp. A tractor-trailer accelerates slowly and needs a long gap to clear crossing traffic, so a misjudged left turn or a late entry into an intersection can leave the trailer blocking lanes. A truck that runs a red light or fails to yield can strike a smaller vehicle with devastating force. Failures to yield and signal violations, by either driver, are common factors.

What the case turns on: These cases often come down to conflicting accounts of who had the green light or the right of way. Signal timing records, intersection and business video, electronic speed data, and the sight lines at the intersection can show which driver entered first and whether either could have avoided the collision.

Wide-Turn Accidents

A tractor-trailer needs substantially more space to turn than a passenger vehicle, and the trailer’s rear wheels follow a tighter path than the tractor, a movement called off-tracking. A truck making a right turn may strike or trap a car, bicyclist, motorcyclist, or pedestrian beside the trailer, or cross into an adjacent lane during the turn.

Crashes may result from starting the turn from the wrong position, failing to signal, failing to check mirrors, turning when another road user is already alongside, or attempting a turn that cannot be completed safely. These crashes are particularly dangerous for bicyclists and pedestrians, who have little protection from the trailer.

What the case turns on: The truck’s turning path, how far the trailer tracked inside it, the geometry of the intersection, and where the other road user was when the turn began. Intersection cameras and nearby business video often provide the clearest evidence.

Jackknife Accidents

A jackknife occurs when the tractor and trailer move out of alignment and the trailer swings toward the cab, sometimes sweeping across several lanes of traffic. Jackknifing can occur when a driver brakes too hard, travels too fast for road conditions, loses traction, or encounters uneven braking between the tractor and trailer. Brake defects, poor maintenance, and improper loading may also contribute.

What the case turns on: Braking and speed data, road and traction conditions, the condition of the brakes and anti-lock system, and how the load was distributed.

A jackknife should not automatically be blamed on the driver. Federal law requires motor carriers to systematically inspect, repair, and maintain vehicles under their control. Our guide to federal motor carrier safety regulations explains these responsibilities in more detail.

Underride and Override Crashes

An underride crash occurs when a smaller vehicle travels beneath part of a truck or trailer. An override occurs when a truck rides over a smaller vehicle. Both can cause catastrophic injuries because the truck or trailer may miss the bumper and crumple zones designed to absorb crash energy and strike the passenger compartment directly.

Rear underride. Federal regulations require qualifying trailers and semitrailers to have rear impact guards. See 49 C.F.R. section 393.86. Rear underride cases may turn on whether the guard was missing, damaged, poorly maintained, or defectively designed, and whether the trailer’s lights and reflective markings were visible, particularly at night.

Side underride. Side underride crashes often occur when a trailer is crossing or blocking travel lanes. The investigation may focus on whether the trailer was visible in the conditions, the truck driver’s actions, and the collision geometry.

Override. An override typically happens when a truck strikes a stopped or slowing vehicle from behind and rides up onto or over it. Because a loaded truck weighs many times more than a passenger car, these crashes can cause fatal injuries. The evidence usually centers on the truck’s speed, braking, and following distance in the seconds before impact.

What the case turns on: Preserving the truck, trailer, and other vehicle can be critical. Impact damage, the condition of the rear guard, and electronic data can show how the vehicles met and whether required safety equipment performed as intended. A potential equipment defect may also require investigation of the trailer or component manufacturer. Our San Diego auto defect attorneys handle these product claims.

Truck Rollover Accidents

Large trucks have a higher center of gravity than passenger vehicles, particularly when carrying tall or heavy loads. A rollover may occur when a truck enters a curve or freeway ramp too fast, makes an abrupt steering maneuver, drops a wheel onto a soft shoulder, or carries improperly distributed or shifting cargo.

California limits covered truck tractors and motortrucks to 55 mph under Vehicle Code section 22406, even where the posted limit for passenger vehicles is higher. But a truck can be traveling below 55 mph and still be moving too fast for a curve, ramp, weather condition, or load.

What the case turns on: The truck’s speed entering the curve or ramp, the roadway geometry, and where and how the cargo was positioned. When loading contributed to the instability, responsibility may extend to the company that loaded or secured the freight.

What Causes Truck Accidents in San Diego?

Officers record a primary cause for each crash. In the 2014–2024 San Diego County data for injury or fatal crashes involving large trucks, unsafe speed was the most common, at 36.3 percent. Improper turning followed at 19.8 percent, then driving under the influence at 8.3 percent and unsafe lane changes at 8.0 percent. Each cause may apply to the truck driver or to another driver.

Officers do not always assign fault to the truck driver. Among crashes in which officers identified an at-fault party, the truck driver was found at fault in about 42 percent. A police report is a starting point, and each case depends on the available evidence. Some causes, such as equipment failures and cargo problems, can require investigation well beyond the crash scene.

Speed, Driver Decisions, and Fatigue

Unsafe speed does not always mean exceeding the posted limit; it includes driving too fast for traffic, weather, a curve, or the load. Many truck crashes trace back to driver decisions made in the seconds before impact, such as following too closely, changing lanes without clearance, or starting a turn that cannot be completed safely.

Other causes may not appear in a police report’s primary-cause field but can surface during the investigation, including driver fatigue and hours-of-service violations, phone use and other distractions, and inadequate driver training or supervision. In one of our cases, a fatigued box-truck driver fell asleep behind the wheel, crossed the Interstate 8 median into oncoming traffic, and struck an RV. Our guide to federal trucking regulations explains the rules that govern driver hours, qualifications, and drug and alcohol testing.

Tire Blowouts, Brake Failures, and Other Mechanical Defects

A tire or brake failure can cause a driver to lose control of a commercial truck with little warning. But a component failure does not necessarily mean the crash was unavoidable. Federal regulations require motor carriers to systematically inspect, repair, and maintain the vehicles under their control. Maintenance records can reveal recurring brake problems, worn tires, unresolved driver complaints, or repairs that should have been made before the truck returned to service.

What the case turns on: The failed component itself, the truck’s inspection and out-of-service history, and prior repair requests or driver complaints. Examining the failed tire, brake, or part can help distinguish poor maintenance from a manufacturing or design defect. That distinction can help identify whether the carrier, a maintenance contractor, a manufacturer, or more than one party may be responsible.

Cargo Shifts, Overloading, and Lost Loads

Improperly loaded or secured cargo can make a commercial truck dangerous even when the driver is otherwise operating normally. Cargo may shift inside a trailer, fall from an open trailer, spill into traffic, or overload an axle, contributing to rollovers, jackknifes, and loss of steering or braking control.

Federal cargo-securement rules require cargo to be contained, immobilized, or secured so that shifting does not affect the truck’s stability or maneuverability. Drivers also have inspection responsibilities under 49 C.F.R. section 392.9.

What the case turns on: Bills of lading and loading records, weight tickets and axle weights, the securement equipment, and communications among the shipper, carrier, and loading company. These records can show whether the carrier loaded the truck or whether a separate shipper or warehouse created the dangerous condition.

Where Truck Crashes Happen in San Diego

From 2014 through 2024, nearly 58 percent of San Diego County’s injury or fatal truck crashes occurred on or near a state highway. Interstate 15 and Interstate 5 alone accounted for more than a quarter of them, as freight moves between the border, the port, and points north. The location can shape the investigation: steep grades, curves, interchanges, construction zones, and border freight operations each raise different evidence questions.

Crashes involving interstate or cross-border shipments may also involve carriers, brokers, and insurers based outside California, which can make the resulting truck accident litigation more complex. Our San Diego truck accident statistics break down crashes by freeway and city.

How Crash Evidence Helps Identify Who Is Responsible

The type of crash is a starting point, not proof of fault. Depending on the evidence, responsible parties may include the driver, the motor carrier, the trailer owner, a freight broker, a shipper or loading company, a maintenance contractor, a parts manufacturer, or a government entity responsible for a dangerous road.

Much of that evidence is time-sensitive. Electronic logging and engine data can be overwritten, and trucks, tires, and brakes may be repaired or returned to service. Our guides to who can be held responsible for a truck accident and the truck accident investigation process explain each step in detail.

Compensation After a Truck Accident

Serious truck crashes can cause brain injuries, spinal cord injuries, amputations, burns, and other life-changing harm. Recoverable damages can include medical expenses, future care, lost income and earning capacity, and pain and suffering. Learn more about common truck accident injuries and the compensation available after a truck accident.

Get Help After a Serious Truck Accident in San Diego

If you or someone you love was seriously injured in a truck accident in San Diego, our San Diego truck accident attorneys, Conor and Leslie Hulburt, can investigate what happened, preserve the evidence, and explain your options.

Call (619) 821-0500 or send us a message through our contact page for a free, confidential case review. There is no attorney fee unless we recover compensation for you.