DUI stop for Weaving or Lane Straddling


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DUI stop for Weaving or Lane Straddling

DUI stop for Weaving or Lane Straddling

CHP DUI Arrest Rearview

A common reason for being stopped in DUI cases is weaving or lane straddling, sometimes known as swerving, while on the highway.  A DUI stop for Weaving or Lane Straddling may be valid, or may be invalid probable cause for a DUI under California law.

DUI stop for Weaving or Lane Straddling – The Law

First, what the law states.  Weaving or Lane Straddling is made illegal under California Vehicle Code section 21658 , which states as follows:

CA Vehicle Code § 21658 states:

Whenever any roadway has been divided into two or more clearly marked lanes for traffic in one direction, the following rules apply:

(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.

(b) Official signs may be erected directing slow-moving traffic to use a designated lane or allocating specified lanes to traffic moving in the same direction, and drivers of vehicles shall obey the directions of the traffic device.

Note that nowhere in this or any sections of the Vehicle Code in California is there any law that prohibits swerving or weaving when driving your car.  Weaving in your lane or touching the dividing lines of the lane are not violations, according to the CA Vehicle Code. As DUI Lawyers in Orange County, we often look at patrol car videos carefully to see if there was actually a violation of any law.

DUI stop for Weaving or Lane Straddling – Probable Cause

First, some law.  The stopping of a vehicle by law enforcement is a “seizure” and, as such, must adhere to the strictures of the 4th Amendment of the Constitution, which prohibits unreasonable searches and seizures.

To be a “reasonable” stop under the 4th Amendment, the officers must have a reason for the stop. If the officer observes the vehicle violate a traffic law and bases the stop on the violation of the traffic law, the 4th Amendment requirements are usually met, and there is a traffic law against swerving or driving recklessly, as above.

A precise legal definition doesn’t exist as to what it means to drive “as nearly as practical within a single lane.” However, the Federal 9th Circuit Court of Appeals gave some guidance on this issue in a case.

DUI stop for Weaving or Lane Straddling – Case Law

In U.S. v. Colin, 314 F.3d 439, the 9th Circuit Court of Appeals dealt with this issue. The arresting officer observed defendant drift onto the solid white fog line of the far side of the right lane for about ten seconds. The defendant’s vehicle then drifted to the left side of the right lane, signaled a lane change, and moved into the left lane. The officer then observed the vehicle drift to the left side of the left lane where its left wheels traveled along the solid yellow line for approximately ten seconds. The defendant’s vehicle then returned to the center of the left lane, signaled a lane change, and moved into the right lane.

The arresting officer then pulled the defendant over for a  violation of California Vehicle Code §21658(a) for lane straddling and conducted a DUI arrest.

The court held that the officer’s stop was illegal, stating as follows:

 “Touching a dividing line, even if a small portion of the body of the car veers into a neighboring lane, satisfies the state’s requirement that that a driver drive as ‘nearly as practical within a single lane’… It is reasonable that a driver with no cars abreast of him might veer slightly within his lane or over the lane lines in the course of making a lane change to ensure that it is safe to do so. In sum, we conclude that the facts, taken together, support the conclusion that [the officer] lacked probable cause to stop [the defendants] for lane straddling.” Id. at 444-445.

The appeals court went on to say, “If a failure to follow a perfect vector down the highway or keeping one’s eyes on the road were sufficient reasons to suspect a person of driving while impaired, a substantial portion of the public would be subject each day to an invasion of their privacy.” Id. at 447.

This is not to say that swerving within a lane cannot be used for a stop for driving under the influence.

It was articulated in People v. Perez, 221 Cal.Rptr. 776, 778, that “pronounced weaving within a lane provides an officer with reasonable cause to stop a vehicle on suspicion of driving under the influence where such weaving continues for a substantial distance.” (emphasis added).

While officers often use the observation of swerving and lane straddling as the precursor to a DUI stop. Such cases are very much fact dependent.

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Contact us if you have any questions about a DUI stop for Weaving or Lane Straddling.  We have handled many such cases and can help you.


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