Legal Information About Weaving or Lane Straddling


Regarding Weaving/Lane Straddling - CVC-21658, Vehicle Code § 21658 mandates:

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.


This Vehicle Code Section is one of the most cited reasons for a stop of a vehicle. It is not weaving outside of a lane – it is weaving within a lane. This is something almost every motorist does every time he or she drives. As such, Courts are careful to ensure that the "weaving within the lane" is so pronounced, and over such a period of time, as to not subject each motorist to a stop.

For example, in U.S. v. Colin, C.A.9 (Cal.)2002, 314 F.3d 439 the Court held that the officer did not have reasonable suspicion to stop the driver for a violation of the California statute prohibiting lane straddling, and requiring vehicle to be driven as nearly as practical entirely within single lane of traffic. The evidence adduced the officer observed the vehicle touch, not cross, the fog line and solid yellow-painted line for approximately 10 seconds on two occasions. The Court held that assuming arguendo that part of the vehicle extending beyond the wheels actually crossed over line, that did not violate the statute's requirement that the vehicle remain as nearly as practical entirely within single lane, because touching the lane line occurred immediately prior to lane changes, and it was reasonable for driver to veer slightly within his lane prior to making lane changes.

In U.S. v. Saldana, C.A.9 (Cal.) 2003, 55 Fed.Appx. 424, 2003 WL 77211, (Unreported), the Court held that the police officer lacked reasonable suspicion to stop motorist for lane straddling under California law, where motorist weaved within his lane and caused his vehicle's tires to touch the lane line without crossing into an adjacent lane. In People v. Butler (1978) 81 Cal.App.3d Supp. 6, the Court held that even though the driving was not “unsafe”, it did not preclude a finding of a violation of CVC § 21658.