Left-turn accidents in California

A left turn across oncoming traffic asks a driver to judge the speed and distance of a car coming at them, and to be right. Most of the time they are. When they are not, the collision tends to be severe, because the impact lands on the side of one vehicle rather than the front. This is general information, not legal advice.

The rule has two halves, and people only know the first

Vehicle Code section 21801 is usually quoted for its first half: a driver intending to turn left, or to complete a U-turn, must yield to all vehicles approaching from the opposite direction that are close enough to constitute a hazard, and must keep yielding until the turn can be made with reasonable safety.

The second half is the part that decides contested cases. Having yielded and given the required signal, the turning driver may proceed — and drivers approaching from the opposite direction must then yield to the turning vehicle. The right of way flips once the turn is lawfully under way.

That matters because it reframes the question. It is not "was the other car coming?" It is whether the oncoming car was close enough to be a hazard at the moment the turn began. A car that was far away and arrived quickly is a different case from a car that was already close.

Sources: Veh. Code, § 21801 (left turn and U-turn — duty to yield, and the oncoming driver's duty once the turn has lawfully begun); § 22350 (basic speed law); CACI No. 700 (a driver must keep a lookout and control the speed and movement of the vehicle), Judicial Council of California Civil Jury Instructions (2026 edition).

Arrow, ball, and what changes between them

• Green arrow. A protected phase. Oncoming traffic faces a red. A driver who enters against it has violated the signal rule, and the turning driver is usually in a strong position.
• Green ball. Permissive. The turn is allowed but unprotected, and the full yield duty sits on the turning driver.
• Flashing yellow arrow. Also permissive, and increasingly common. It signals the turn is allowed after yielding.
• Yellow, and the tail of the phase. A driver already lawfully in the intersection waiting to turn may complete the turn when it is safe. This is where signal timing evidence earns its keep.

Which phase was displayed is often disputed and is usually answerable. Municipal signal timing plans exist, and the intervals are fixed. So is whether the intersection has a protected phase at all.

Signal and stop-sign right of way generally: intersection accidents.

"He came out of nowhere"

This is the most common description a turning driver gives, and it is usually sincere. A vehicle approaching at high speed covers ground far faster than a driver's judgment expects, and a car that was a safe distance away when the turn began can be on top of the turn before it completes.

The same phrase covers a second thing: a vehicle that was genuinely there and was not seen. Narrow profiles are the usual reason, which is why motorcycles feature so heavily in this crash type. That version is covered at motorcycle left-turn collisions, where the perception problem is the heart of the case rather than a detail in it.

Neither version is a defense on its own. What turns it into one is evidence of the oncoming speed.

Proving the oncoming speed

• Crush and damage severity, which scales with closing speed.
• Post-impact travel — how far each vehicle moved, and in what direction.
• Skid, scuff, and gouge marks, and the absence of them, which suggests no braking.
• Event data recorders. Many vehicles record pre-impact speed and braking for a few seconds. The data can be overwritten, so preservation matters early.
• Signal timing, which fixes the sequence against a clock.
• Cameras — intersection, transit, business, doorbell, dash.

How these pieces get assembled: how fault is decided in a car accident.

When the roadway is part of the problem

Some left-turn intersections produce collisions repeatedly, and the reason is the design rather than the drivers — an obstructed sight line, a permissive phase where the traffic volume calls for a protected one, or a turn pocket that puts a waiting car at a bad angle. A claim against the public entity responsible for the roadway is possible, and it runs on a much shorter clock than an ordinary claim.

Claims against a government entity · highway versus surface street.

Common questions

Is the left-turning driver always at fault?

No, though they start behind. Vehicle Code section 21801 requires a driver turning left to yield to oncoming traffic close enough to be a hazard. But the same section has a second half: once the turning driver has yielded and signalled and begun the turn, oncoming drivers must yield to them. A turn that was lawful when it began does not become unlawful because someone sped into it.

What difference does a green arrow make?

A large one. A green arrow gives the turn a protected phase — oncoming traffic has a red. A driver who enters against that red is the one who violated a rule. On a permissive green ball the turn is allowed but not protected, and the yield duty is fully on the turning driver.

The other driver was speeding. Does that matter?

Yes, in two ways. It bears on whether the oncoming car was close enough to be a hazard when the turn began, which is the statutory test, and it is its own violation of the basic speed law. Speeding rarely erases the turning driver’s share, but it regularly moves the percentages.

How is oncoming speed proved after the fact?

Damage severity and crush depth, the distance vehicles travelled after impact, skid or scuff marks, signal timing, event data recorder downloads from either vehicle, and any camera that caught it. Driver estimates on their own are weak evidence in both directions.