A common ground for a DUI traffic stop is "weaving". California Vehicle Code Section 21658(a) provides that "A vehicle shall be driven as nearly as practical within a single lane and shall not be moved from the lane until such movement can be made with reasonable safety". Weaving in the roadway, even for a short distance may be sufficient probable cause for a vehicle stop as a result of the decision in Arburn v. DMV (2007) 151 Cal.App.4th 1480. However, in that case, the driver almost hit a curb. There is a long line of previous decisions on point in California.
In People v. Perez (1985) 175 Cal.App.3d Supp. 8, the court addressed the legality of a traffic stop where the driver was stopped for "pronounced weaving" over a distance of three-quarters of a mile. In People v. Bracken (2000) 83 Cal.App.4th Supp. 1, the driver was observed to weave within the lane for one-half mile. In People v. Russell (2000) 81 Cal.App.4th 96, the officer stopped the driver after observing him travelling 10 miles under the speed limit and "repeatedly drifting around within its lane and sometimes out of its lane". In People v. Perkins (1981) 126 Cal.App.3d Supp. 12, the defendant drove his vehicle 20 miles under the speed limit and was "weaving abruptly from one side of the lane to another". In all of these cases, the courts upheld the legality of the traffic stop.
However, it is apparent from the above cases that weaving for a short distance where the weaving is not pronounced or aggravated, would not amount to good probable cause for a traffic stop.
In the federal case of U.S. v. Colin (9th Cir.2002) 314 F.3d 439, the court found a stop to be illegal where there was no weaving for a "substantial distance" and where there was no "pronounced" weaving. In that case the vehicle simply touched the right fog line and the center yellow line each for 10 seconds.
An allegtion of weaving within a lane justifying a traffic stop must be critically examined with the above case law in mind. In the event that the officer fails to provide a factual basis for "pronounced" weaving over a "substantial distance", a Motion per Penal Code 1538.5 should be filed to suppress all evidence, including breath and blood test evidence flowing from an unlawful traffic stop.
If you have questions concerning probable cause in a DUI case in Los Angeles, please call Los Angeles DUI attorneys at Gold & Witham for a case evaluation.