How to Prove Liability in a Phoenix Left-Turn Auto Accident When the Other Driver Claims You Were Speeding
In Phoenix left-turn crashes, the turning driver is typically presumed at fault because Arizona law requires left-turning vehicles to yield to oncoming traffic. But insurers often try to shift blame by alleging the straight-through driver was speeding to reduce payouts under Arizona’s comparative fault rules. This article explains the evidence and legal standards Phoenix attorneys use to prove liability when the other driver claims you were speeding.
Why speeding becomes the go-to defense in Phoenix left-turn collisions
Left-turn crashes at Phoenix intersections are common because they combine multiple hazards: time pressure at yellow lights, obstructed sight lines, and misjudged closing speeds. When the left-turning driver (or their insurer) knows Arizona law generally requires left-turning traffic to yield, the fastest way to reduce exposure is to argue the oncoming driver was speeding.
That argument matters because Arizona applies a “pure comparative fault” system. Even if the other driver caused the crash, they can attempt to reduce what they owe by assigning you a percentage of fault for excessive speed. The litigation question becomes twofold: (1) who violated the right-of-way rule, and (2) can the defense prove your speed was unreasonable and a cause of the collision.
The core Arizona law: the left-turn driver must yield
Most Phoenix left-turn liability analyses begin with Arizona’s left-turn yielding rule. Under A.R.S. § 28-772, a driver intending to turn left within an intersection must yield the right-of-way to oncoming traffic that is within the intersection or so close as to constitute an immediate hazard.
In practical terms, that means a left-turn driver must not “take a chance” and cut across the path of an oncoming vehicle unless it is reasonably safe. If a collision occurs in the oncoming lane while the turning vehicle is crossing, that fact pattern often strongly supports liability against the left-turning driver—unless the defense can credibly show the oncoming driver’s conduct (like extreme speeding) created the “immediate hazard” problem.
What “immediate hazard” usually means in real cases
Whether an oncoming car was an “immediate hazard” depends on distance, speed, visibility, and timing. A driver turning left cannot excuse a bad decision by saying, “I didn’t think they were coming that fast,” if reasonable judgment would have required waiting. However, if the oncoming driver was traveling far above the speed limit (or accelerating aggressively toward the intersection), the defense may argue the left-turn driver could not reasonably gauge the closing speed.
Arizona comparative fault: speeding only matters if it’s proven and causal
Arizona’s comparative fault framework allows damages to be reduced by the percentage of fault assigned to the plaintiff. But “you were speeding” is not a magic phrase that automatically reduces your recovery. To be meaningful, the allegation must be supported with evidence and tied to causation.
Two key points Phoenix attorneys focus on:
- Proof: Was your speed measured or reliably reconstructed, or is it speculation from a stressed driver?
- Causation: Even if you were over the limit, did that actually cause the collision, or would it have happened anyway because the left-turn driver failed to yield?
What evidence actually proves (or disproves) speeding in a Phoenix left-turn crash
Speed is a technical fact. The more your case relies on objective data rather than opinions, the harder it is for an insurer to inflate comparative fault. In Phoenix left-turn cases, the strongest evidence typically falls into these categories.
1) Crash scene documentation: skid marks, gouge marks, and impact points
Physical roadway evidence can support a speed analysis when it is photographed and measured quickly. Skid length, yaw marks (curved tire marks), and the location of debris fields can help a reconstruction expert estimate pre-impact speed and vehicle trajectories.
Why timing matters: In a busy Phoenix corridor, marks can fade or be overwritten within days. Early scene investigation—often within 24–72 hours—can be decisive.
2) Vehicle “black box” data (EDR) and infotainment telematics
Many vehicles store event data recorder (EDR) information such as speed, braking, throttle position, and seatbelt usage in the seconds before a crash. If your vehicle (or the other driver’s vehicle) has EDR data, it can corroborate your speed and braking response.
Attorneys often send spoliation letters early to preserve vehicles and data. If a vehicle is repaired or salvaged before imaging the EDR, critical evidence can be lost.
3) Intersection and roadway video: city cameras, business surveillance, and dashcams
Phoenix collisions frequently occur near businesses with exterior cameras. Even if the crash is not fully captured, video can show:
- Traffic signal phase timing (who had the green/yellow)
- Relative speed (frame-by-frame movement over known distances)
- The left-turn driver’s gap selection and hesitation
Dashcam footage is even more powerful, especially if it captures your speed readout, the light color, and the other vehicle initiating the turn.
4) 911 calls and contemporaneous witness statements
Witnesses often say, “They were flying,” but those statements can be unreliable unless anchored to specifics. Strong witness evidence tends to include details like:
- Where the witness was positioned and what sight lines existed
- Whether the witness observed braking or lane changes
- How long the witness observed each vehicle before impact
Statements captured immediately (bodycam, 911 recordings, or written statements at the scene) often carry more weight than later recollections.
5) Police reports: useful, but not the final word
Officers may cite a driver for failure to yield or include an opinion about speed. But in many intersection crashes, officers did not witness the collision and may not perform a full reconstruction.
Attorneys treat the report as a starting point: helpful for identifying parties, witnesses, and initial diagrams—but not a substitute for measurements, EDR, or expert analysis.
How Phoenix attorneys build a liability theory when the defense claims speeding
To prove the left-turn driver’s liability while neutralizing the speeding allegation, attorneys typically build a timeline that answers three questions: (1) who had the duty to yield, (2) when did the left-turn begin, and (3) could a reasonable driver have completed the turn safely given the oncoming traffic’s position and lawful speed.
Step 1: Lock down the intersection conditions
Key facts include:
- Lane configuration (protected left arrow vs. permissive green)
- Speed limit, signage, and sight distance (including landscaping or parked vehicles)
- Signal timing and phase sequences (often available through city traffic engineering data)
If the left turn was permissive (no arrow), the duty to yield is front and center. If it was protected, liability may shift to red-light running or signal confusion.
Step 2: Use physics and data to set realistic speed bounds
A reconstruction expert can combine EDR, crush damage analysis, road friction, and post-impact travel to estimate speed. Even when the exact mph is disputed, experts can often establish a credible range.
This matters because insurers sometimes imply “speeding” without committing to a number. For comparative fault, the defense must persuade a jury (or adjuster) that the speed was not just slightly above the limit, but meaningfully contributed to the inability to avoid the crash.
Step 3: Prove the crash would have occurred even at the speed limit (causation rebuttal)
A common and effective rebuttal is a “time-distance” analysis: if the left-turn driver initiated the turn when you were so close that even a lawful-speed driver could not have avoided impact, then speeding becomes less relevant.
Example: You are traveling eastbound at 40 mph in a 35 mph zone. The other driver makes a permissive left turn across your lane when you are 90 feet from the conflict point. A reconstruction may show that at 35 mph you still would not have had sufficient time to stop or evade given perception-reaction time and braking distance. The primary cause remains the failure to yield.
Common insurance tactics in Phoenix left-turn cases—and how to counter them
Tactic: “You must have been speeding because the damage is severe”
Crash severity can be influenced by vehicle weight, bumper height mismatch, angle of impact, and modern crumple zones. Attorneys counter this with EDR data, reconstruction, and photos showing overlap and intrusion patterns that explain damage without assuming excessive speed.
Tactic: “No skid marks means you weren’t paying attention or were speeding”
Modern vehicles with ABS can leave faint or intermittent marks. Also, many drivers do not have time to brake before impact in sudden left-turn violations. EDR braking data and reaction-time analysis can address this directly.
Tactic: “You could have avoided it if you weren’t speeding”
This argument is essentially a causation claim. It can be tested with time-distance math, signal timing, and visibility studies. If the left-turn driver “entered the box” when you were already too close, avoidance may be unrealistic regardless of speed.
Tactic: “You were speeding because you were late / driving aggressively”
Character-based insinuations don’t prove mph. Attorneys keep the focus on objective evidence—EDR, video, measurements—and move to exclude irrelevant speculation when appropriate.
Phoenix-specific proof opportunities: where speed and right-of-way evidence often comes from
In Phoenix, liability evidence frequently exists—but it is time-sensitive. Common sources include:
- Business corridors: Gas stations, strip malls, and drive-thrus often have cameras facing arterials and intersections.
- Rideshare and delivery vehicles: Many have dashcams or telematics logs that can corroborate traffic flow and timing.
- City data: Traffic signal timing, maintenance
