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self-study / Alternative Dispute Resolution

Jan. 28, 2019

When speed surveys are necessary

East County Hall of Justice

Jason A. Clay

Supervising Judge, Alameda County Superior Court

Misdemeanor arraignments/pretrials

University of Colorado School of Law


The objective of this article and accompanying self-study test is to increase readers' understanding of when speed surveys are necessary and what constitutes a valid engineering and traffic survey. A valid ETS is required to establish a speed trap was not involved in an infraction case, and can make the difference between a conviction and an acquittal at a speeding trial.

Speed Traps

California Vehicle Code Section 40802 defines a speed trap as either determining the speed of a vehicle by timing a vehicle between fixed marks on a highway, or speed determined by radar or laser (lidar) on a highway where a current valid speed survey is required.

If a speed trap is involved, the officer's testimony in an infraction trial is legally incompetent and cannot be considered. CVC Section 40804. Hence, lack of proof of a valid survey, when required, makes all testimony on speed inadmissible.

Survey Required

An ETS is required when enforcement of the basic speed law (CVC Section 22350) involves the use of radar or lidar. CVC Section 40802(a)(2).

The basic speed law makes it an infraction to travel at any speed unsafe for conditions involved. CVC Section 22350 provides, "No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or property." The burden is on the prosecution to establish that the speed was unreasonable for the conditions, and pursuant to the terms of the statute, slower than posted speed may also be unlawful.

Pursuant to CVC Section 22351(b), speed is presumed to be unreasonable when it is in excess of prima facie speed limits specified in CVC Section 22352. Speed is also presumed unreasonable when it is in excess of prima facie speed limits established as authorized in other parts of the CVC (e.g., CVC Section 22354 and CVC Section 22358). In contrast to speeding violations under CVC Section 22350, pursuant to CVC Section 22351(b), the burden is on the defendant to prove that speed was not unreasonable.

When the speed limit is set below 65 mph, the decision must be based on an ETS. CVC Sections 22354, 22358. If based on a valid ETS, and appropriate signs giving notice of speed are erected on the highway, the speed becomes the prima facie speed limit. See CVC Section 22352.

Speed Survey Not Required

Speed surveys are only required to disprove the existence of speed traps in violations involving the prima facie speed. CVC Section 40802(a)(2); People v. DiFiore, 197 Cal. App. 3d Supp. 26 (1987).

Thus, surveys are not required for the following speed cases:

• CVC Section 22349(a): speed over 65.

• CVC Section 22349(b): speed over 55 (all two-lane undivided roads).

• CVC Section 22348(b): speed over 100.

• CVC Section 22356(b): exceeding 70 mph on limited access highway.

• CVC Section 22406: exceeding 55 mph in specified vehicles, including big rig vehicles and school buses with children, and when towing any trailer.

Surveys are also not required for reduced speed limits:

• CVC Section 22352(a): 15 mph -- railway grade crossing and alleys.

• CVC Section 22352(b): 25 mph -- business or residence district, school zones when children are present, properly posted senior centers when seniors are present.

In addition, surveys are not required for local roads. See CVC Section 40802(a)(2).

Elements of a Valid Survey

CVC Section 627(b) provides, "An engineering and traffic survey shall include, among other requirements deemed necessary by the department, consideration of all of the following: [¶] (1) Prevailing speeds as determined by traffic engineering measurements. [¶] (2) Accident records. [¶] (3) Highway, traffic, and roadside conditions not readily apparent to the driver."

A survey must record the speeds of normal motorists during varied times and conditions. It must determine the speed at which 85 percent of the drivers drive that segment, and then set the speed limit by rounding to the nearest 5 miles per hour of the 85th percentile. See Caltrans Traffic Manual, Section 8-03.3, subd. (B).

As explained by People v. Goulet, 13 Cal. App. 4th Supp. 1 (1992), "A local authority may, based on a survey, set a prima facie speed limit ... which is most appropriate to facilitate the orderly movement of traffic and is reasonable and safe." An ETS must be prepared "in accordance with methods determined by the Department of Transportation." CVC Section 627, subd. (a). "Methods required by the Department of Transportation are published in a traffic manual." Goulet. Quoting the California Manual on Uniform Traffic Control Devices, Goulet indicated, "'Speed limits should be established preferably at or near the 85 percentile speed, which is defined as that speed at or below which 85 percent of the traffic is moving.'"

There are exceptions to rounding the speed limit to the nearest 5 mph increment. If there are conditions not readily apparent to the driver, the speed may be reduced by 5 mph from the nearest 5 mph increment. See Goulet. The factors justifying the reduction must be documented on the ETS. CVC Section 627(b). Conditions not readily apparent include vehicles, bicycles, or pedestrians not visible to the motorist; access points or road dips, grades or curves not visible to the motorist; and schools, hospitals, or senior centers in close proximity not apparent to drivers. See California Manual for Setting Speed Limits Section 3.4.4.

Width, curvature, grade and surface conditions readily apparent to a driver, in the absence of other factors, do not justify a 5 mph speed reduction. CVC Section 22358.5. In situations where the California Manual on Uniform Traffic Control Devices would require speed limits be rounded up to the nearest five miles per hour of the 85th percentile of the free-flowing traffic, the speed limit may, instead, be rounded down to the lower 5 mph increment. CVC Section 21400(b). However, after such a reduction, it then cannot be reduced further for any reason. CVC Section 21400(b).

Lifespan of Surveys

An ETS must have been prepared within five years of the date of the violation. CVC Section 40802(a)(2). But the ETS may be extended to seven or 10 years.

Pursuant to CVC Section 40802(c), to extend a survey to seven years, the prosecution must prove at trial all the following:

• The officer must have completed a 24-hour Peace Officers Standards and Training (POST) certified radar operator course.

• If lidar was used, the officer must have also completed two-hour POST certified lidar course.

• The device must be approved by the National Traffic Highway Safety Administration (NTHSA).

• The device must have been calibrated by an independent certified facility within three years prior to the date of the violation.

Under CVC Section 40802(c)(2), in order to extend a survey to 10 years, all the requirements to extend the survey to seven years must be proved, plus a registered highway safety engineer evaluated that section of highway and determined that no significant changes in roadway or traffic conditions have occurred.


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