Common Causes of Bicycle Accidents in San Diego

Most bicycle crashes involving cars follow recognizable patterns. A driver turns across a cyclist's path, passes too closely, drifts into a bike lane, opens a door into traffic, or simply fails to see a rider who was there to be seen.

California generally gives people riding bicycles the same rights and responsibilities on the road as drivers. When a motorist violates those rules or fails to use reasonable care, that conduct can establish responsibility for a crash.

This guide explains the most common driver-caused bicycle accidents in San Diego, the California traffic laws that apply, and the evidence that can help determine what happened. For local crash numbers, locations, and trends, see our guide to San Diego bicycle accident statistics and high-risk areas.

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Common Driver Mistakes That Cause Bicycle Crashes

Some bicycle crashes involve unusual circumstances, but serious collisions with motor vehicles repeatedly involve several types of driver error:

• Failing to yield at intersections
• Turning across a cyclist's path
• Passing a bicycle too closely
• Drifting into a bike lane or shoulder
• Distracted driving
• Rear-ending a cyclist
• Opening a vehicle door into a cyclist's path
• Driving too fast for conditions
• Driving under the influence
• Aggressive driving or road rage

How the collision happened often determines which traffic laws apply and what evidence is most important.

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1. Failure to Yield at Intersections

Intersections create some of the most dangerous conflicts between drivers and cyclists.

A driver may stop, look for cars, and begin moving without recognizing an approaching bicycle. Other drivers see the cyclist but misjudge how quickly the bicycle is approaching.

Left-Turn Bicycle Crashes

A common pattern occurs when a driver turns left across the path of an oncoming cyclist.

Under California Vehicle Code section 21801, a driver making a left turn must yield to approaching traffic that is close enough to create a hazard during the turn.

Cyclists can be difficult for drivers to judge because bicycles are smaller than motor vehicles. That does not excuse a driver from yielding.

Evidence in a left-turn case may include:

• Traffic or surveillance video
• Witness statements
• Vehicle and bicycle damage
• Signal timing
• Skid marks and debris
• GPS or cycling-computer data
• The driver's statements
• The cyclist's speed and location before impact

A driver's statement that they "never saw the bicycle" does not necessarily establish a defense. In many cases, the more important question is whether the cyclist was visible and whether a careful driver should have seen them before turning.

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2. Right-Turn Crashes Across Bike Lanes

A right-turn crash, sometimes called a "right hook," occurs when a driver turns across the path of a cyclist traveling in the same direction.

The driver may pass the cyclist and immediately turn right. In other cases, the bicycle is traveling in a bike lane beside vehicles that are slowing or preparing to turn.

California law specifically addresses this situation. When a driver must cross an adjacent bicycle lane to make a turn, Vehicle Code section 21717 requires the driver to enter the bicycle lane before making the turn. Right turns must also comply with Vehicle Code section 22100.

A driver should not simply turn across an occupied bike lane without first accounting for the cyclist.

Right-turn cases often depend on the relative positions of the vehicle and bicycle before the crash. Video can be especially important because it may show whether the driver passed the cyclist, whether a turn signal was used, and when the vehicle entered the bike lane.

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3. Unsafe Passing and Sideswipe Crashes

Cyclists are particularly vulnerable when vehicles pass them at speed.

California's Three Feet for Safety Act requires drivers to leave at least three feet between the vehicle and bicycle when passing.

The law now goes further. When a vehicle and bicycle are traveling in the same lane and another lane traveling in the same direction is available, the driver must change into the other lane before passing when doing so is practicable and lawful.

If roadway or traffic conditions make the required clearance impossible, the driver must slow to a reasonable and prudent speed and pass only when it can be done without endangering the cyclist.

Unsafe passing can cause several types of crashes:

• A vehicle directly sideswipes the bicycle
• A mirror strikes the cyclist
• A driver moves back into the lane too soon
• A cyclist is forced off the roadway
• A cyclist loses control while avoiding the passing vehicle

These cases often come down to vehicle position, lane width, speed, and the amount of room available to the driver.

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4. Distracted Drivers Drifting Into Bike Lanes or Shoulders

A few seconds of inattention can move a vehicle several hundred feet down the road.

That becomes especially dangerous when a cyclist is riding in a bike lane, shoulder, or along the right side of the roadway. A distracted driver may gradually drift out of the travel lane and strike the cyclist from the side or behind.

Phone use is one potential source of distraction. Vehicle Code section 23123.5 restricts drivers from holding and operating handheld wireless devices while driving, subject to limited exceptions.

Other distractions can include:

• Navigation systems
• Eating or drinking
• Looking at passengers
• Reaching for objects
• Adjusting vehicle controls
• Looking away from the roadway

Proving distraction can require more than the driver's account. Phone records, vehicle data, video, witness testimony, and the path of the vehicle before impact may help explain why a driver left the travel lane.

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5. Rear-End Bicycle Crashes

Some of the most serious bicycle crashes occur when a driver approaches a cyclist from behind.

These collisions can happen on high-speed roads, narrow streets, freeway approaches, rural roads, or anywhere a driver fails to recognize and react to a cyclist ahead.

Common issues include:

• Driver distraction
• Excessive speed
• Inattention
• Impairment
• Following too closely
• Failure to move over when passing
• Poor visibility

A rear-end collision does not automatically answer every question about fault. Investigators still need to determine where the cyclist was riding, what the driver could see, the driver's speed and path, and whether there was sufficient time and distance to avoid the crash.

In serious cases, vehicle event data, electronic records, photographs, video, and accident reconstruction can help determine when the driver should have perceived and reacted to the cyclist.

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6. Dooring Accidents

A dooring crash occurs when someone in a parked vehicle opens a door into the path of an approaching cyclist.

Under Vehicle Code section 22517, a person may not open a vehicle door on the side available to moving traffic unless it is reasonably safe and can be done without interfering with that traffic.

For cyclists, the consequences can be severe.

A rider may strike the door directly, be thrown over it, or swerve into a moving traffic lane while trying to avoid it.

Dooring risks are particularly relevant on streets where curbside parking sits immediately beside a bicycle lane or other area used by cyclists.

The person who opened the door may be responsible even if that person was a passenger rather than the driver. Depending on the circumstances, other parties may also need to be investigated. Our guide to potential defendants in bicycle accident cases explains when responsibility can extend beyond the obvious driver.

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7. Speeding and Driving Too Fast for Conditions

The posted speed limit is not the only rule governing vehicle speed.

California's basic speed law, Vehicle Code section 22350, prohibits driving faster than is reasonable or prudent for weather, visibility, traffic, roadway conditions, and other circumstances.

Speed matters in bicycle crashes for two reasons.

First, a faster driver has less time to perceive and respond to a cyclist, particularly at intersections, curves, driveways, and areas with limited sight distance.

Second, speed can dramatically affect the severity of the resulting impact.

A driver can therefore be negligent even when traveling below the posted limit if the circumstances called for a slower speed.

Evidence such as vehicle data, surveillance video, skid marks, crush damage, and accident reconstruction may help determine vehicle speed before impact.

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8. Driving Under the Influence

Alcohol and drugs can impair judgment, perception, reaction time, and vehicle control.

California Vehicle Code section 23152 prohibits driving under the influence of alcohol or drugs and separately prohibits driving with a blood alcohol concentration of 0.08 percent or more.

For a cyclist, an impaired driver's mistake can be catastrophic. The driver may drift from the lane, fail to recognize the cyclist, misjudge a turn, speed, run a traffic signal, or react too late to avoid a collision.

Evidence in an impaired-driving case may include the police investigation, chemical testing, body-camera footage, witness observations, receipts, video, and criminal proceedings arising from the crash.

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9. Aggressive Driving and Road Rage

Cyclists sometimes encounter drivers who follow too closely, intentionally pass within inches, cut them off, honk aggressively, or use a vehicle to intimidate them.

Those cases are different from an ordinary moment of inattention.

Important evidence may include helmet-camera or dashcam video, witness testimony, prior interactions between the driver and cyclist, statements made at the scene, and the driver's conduct immediately before and after the incident.

When conduct is intentional or particularly egregious, additional legal issues may arise beyond an ordinary negligence claim.

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What If the Road Contributed to the Crash?

Not every bicycle accident is caused solely by a driver.

A dangerous intersection, defective signal timing, pothole, unsafe roadway design, missing warning, obstructed sightline, or other roadway condition may contribute to a crash.

When that happens, responsibility may extend to a city, county, Caltrans, contractor, or another party responsible for the roadway.

Public-entity cases are different from ordinary driver negligence claims and have much shorter claim deadlines. Our guide to road hazards and bicycle accidents in San Diego explains these cases in more detail.

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How Do You Prove What Caused a Bicycle Crash?

The type of crash often provides the starting point, but determining fault requires evidence.

Important evidence may include:

• Traffic and surveillance video
• Dashcam or helmet-camera footage
• Witness statements
• Police reports
• Photographs of the scene
• Vehicle and bicycle damage
• Skid marks and debris
• Cellphone records
• Vehicle electronic data
• GPS and cycling-computer data
• Traffic signal timing
• Roadway measurements
• Accident reconstruction

Some evidence disappears quickly. Surveillance footage can be overwritten, vehicles can be repaired, roadway conditions can change, and witnesses can become difficult to locate.

For a detailed discussion of what should be collected and preserved, see our guide to gathering evidence after a bicycle crash in San Diego.

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Can a Cyclist Be Partly at Fault?

Yes. California follows comparative negligence, which means responsibility can be divided between the people or entities whose conduct contributed to the injury.

An insurance company may argue that the cyclist entered the intersection unsafely, violated a traffic law, was riding in an improper position, lacked required lighting, or otherwise contributed to the crash.

Those allegations do not automatically defeat a claim. The evidence must establish whether the cyclist actually did something negligent and whether that conduct contributed to causing the collision or injuries.

Our guide to comparative negligence in bicycle accident cases explains how California's system affects compensation.

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What Should You Do After a Bicycle Crash?

After a serious bicycle accident, your health comes first. Get medical care and report the crash.

When possible, preserve the bicycle, helmet, clothing, photographs, video, GPS data, and information about potential witnesses. Avoid repairing or discarding the bicycle before it has been documented.

Early investigation can be particularly important when the crash involves surveillance video, a hit-and-run driver, a commercial vehicle, disputed traffic signals, or a potentially dangerous roadway condition.

Our guide to what to do after a bicycle accident in San Diego provides a step-by-step explanation.

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Talk to a San Diego Bicycle Accident Attorney

Serious bicycle crashes require more than identifying the obvious driver error. The evidence must show how the collision happened, why it happened, and who was responsible.

Hulburt Law Firm represents people seriously injured in bicycle accidents throughout San Diego County. We investigate the crash, preserve critical evidence, identify all responsible parties, and prepare serious cases for trial when necessary.

Call (619) 821-0500 or contact us through our online form for a free, confidential case review.