CVC 21658(a)Eligible for written declaration

Unsafe Lane Change

Not driving as nearly as practical entirely within a single lane, or moving from the lane before the move can be made with reasonable safety.

Reviewed by the TicketClear teamLast reviewed October 10, 2026

Fine: $234DMV Points: 1🏫 Traffic school may be available

Insurance: insurers must weigh your driving safety record first (Insurance Code 1861.02(a)), and more than one violation point counted under Vehicle Code 12810(a) to (d), (f), (i)(1) or (j) in the previous three years ends Good Driver Discount eligibility (Insurance Code 1861.025(b)(1)).

This guide is for general educational purposes only and does not constitute legal advice. TicketClear is a self-help document preparation service — we are not attorneys and do not represent clients. Review all prepared documents carefully before submitting. Fine amounts are estimates and vary by county and surcharge schedule.

What is a Unsafe Lane Change ticket?

CVC 21658 says that whenever a roadway has been divided into two or more clearly marked lanes for traffic in one direction, (a) a vehicle shall be driven as nearly as practical entirely within a single lane and shall not be moved from the lane until such movement can be made with reasonable safety, and (b) official signs may direct slow-moving traffic to use a designated lane or allocate specified lanes to traffic moving in the same direction, and drivers shall obey them.

Ask your insurer how a conviction affects your policy.

What the Law Says

(a) A vehicle shall be driven as nearly as practical entirely within a single lane and shall not be moved from the lane until such movement can be made with reasonable safety.

What the Officer Must Prove

1You were on a roadway divided into two or more clearly marked lanes for traffic in one direction
2You did not drive as nearly as practical entirely within a single lane, or moved from the lane before the movement could be made with reasonable safety

Arguments Commonly Raised for Unsafe Lane Change

General information: arguments drivers commonly raise for this code section. Whether any applies depends on your own facts.

Reasonable safety

CVC 21658(a) allows moving from the lane once the movement can be made with reasonable safety. Describe what you checked and the traffic around you.

As nearly as practical

The section requires driving as nearly as practical entirely within a single lane. Describe the road, its markings and any hazards.

Clearly marked lanes

The section applies where the roadway has been divided into two or more clearly marked lanes for traffic in one direction. Describe the lane markings.

⚠️ Common Mistakes

✗Leaving out what you checked before changing lanes
✗Not photographing the lane markings

What this code section covers (general information)

CVC 21658(a) — Unsafe Lane Change. Not driving as nearly as practical entirely within a single lane, or moving from the lane before the move can be made with reasonable safety.

Eligible for Trial by Written Declaration: generally yes.

This is general information about CVC 21658(a). It is not advice about your citation, and TicketClear does not evaluate anyone's facts. Whether any of it applies depends on your own facts. For advice about your situation, consult a licensed California attorney.

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Traffic School Option

A conviction adds 1 DMV point. The court may let you complete traffic school. If it is the only ticket you have done traffic school for in 18 months, the record is kept confidential and no point is counted (Vehicle Code 1808.7(a)). Traffic school is not available for a violation in a commercial motor vehicle (Vehicle Code 42005(c)(1)). If you hold a commercial driver license, the record is not kept confidential (Vehicle Code 1808.7(b)). Check your notice or your court's website for your options.

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