2023 Engineering and Traffic Survey
PLACENTIA, CA
LIN Consulting, Inc.
Traffic, Civil, and Electrical Consulting Engineers
Prepared by:
LIN Consulting, Inc.
For:
City of Placentia
March 13, 2024
2023 Engineering and Traffic Survey (3/13/2024)
City of Placentia 2023 Engineering and Traffic Survey
February 2024, Prepared by LIN Consulting, Inc.
This Engineering and Traffic Survey has been prepared under the direction of the following registered engineers. The registered Civil Engineer attests to the technical information contained herein and have judged the qualifications of any technical specialists providing engineering data upon which recommendations, conclusions and decisions are based.
Mohammad Qureshi, P.E., T.E.
LIN Consulting
Approved:
Kyra Tao, P.E.
Transportation Manager
T v3ir. Civil, F7erinrwl Cowruliin y Engineer
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2023 Engineering and Traffic Survey (3/13/2024)
TABLE OF CONTENTS
1.0 Executive Summary 1
2.0 Introduction 8
2.1 Purpose and Need for E&TS 8
2.2 Study Locations 8
3.0 E&TS Methodology 9
3.1 State and Federal Regulations and Policies 9
3.1.1 California Vehicle Code (CVC) 9
3.1.2 California Manual on Uniform Traffic Control Devices (CA MUTCD) 12
3.1.3 Previous Studies 13
3.2 Data Collection 15
3.2.1 Speed Survey 15
3.2.2 Average Daily Traffic 16
3.2.3 Crash Data Calculation 16
4.0 Conclusions 20
LIST OF TABLES
Table 1-1. Speed Zone Recommendations 2
Table 3-1. 2024 Average Daily Traffic and Crash Rate Calculation 17
APPENDICES
Appendix A: Equipment Certification
Appendix B: Speed Survey
Appendix C: Average Daily Traffic
Appendix D: Crash Summary
Appendix E: E&TS Sheets
Traffic. Civil. Electrical Coaru/eing i'ng
2023 Engineering and Traffic Survey (3/13/2024)
1.0 EXECUTIVE SUMMARY
The intent of this Engineering and Traffic Survey (E&TS) is to establish and review prima facie speed limit zones set on certain public roadways within the jurisdiction of the City of Placentia (City). Through this process, the E&TS goal is to obtain voluntary compliance in appropriately determined speed limits by gaining public confidence in a fair process, while also considering overall roadway safety with limited need for regular enforcement.
This E&TS meets the criteria set forth and establishes these speed limits in compliance with California Vehicle Code (CVC) 40802. In coordination with the City of Placentia, it was determined that 73 segments were candidates for speed zone surveys.
CVC provides the legal framework for cities and counties to enact local speed limit zones within their jurisdiction. California law states that speed limits are based upon an E&TS that includes prevailing speeds, accident records, and highway, traffic and roadside conditions not readily apparent to the drivers as well as other factors as defined in CVC 627. The E&TS also satisfies the requirements set forth in CVC 40802, which defines a "speed trap": a practice that is prohibited by State law whereby a speed limit is set arbitrarily low on streets other than streets classified as "local" streets. Furthermore, CVC prohibits speed reductions based on conditions that are already apparent to a reasonable driver. State law also governs how speed limits may be rounded to the nearest 5 mph increment based upon prevailing speeds.
Based on the findings in this E&TS for each speed zone, it is recommended that posted speeds remain as currently established and posted.
A summary of all recommended speed zones surveyed are provided by location in Table 1-1.
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Table 1-1. Speed Zone Recommendations
Existing
Posted 85th 0/0
No. Street Name From to Speed Speed
Limit (mph)
(mph)
85th %
Speed
Rounded
(mph)
Recommended
Posted Speed
(mph)
(311312024)
Reason for Recommended
Speed Limit
All America Chapman Closest to 85th percentile
1Wa Alta Vista St Ave 35 35.8 35 35 speed
Y
Per CA MUTCD Option 2,
rounded down to the
25 29.0 30 25 nearest 5 mph increment
below the 85th percentile
speed
3 Alta Vista St Kraemer Rose Dr 45 45.4 45 45 Closest to 85th percentile Blvd speed
4 Alta Vista St Rose Dr Jefferson St 45 46.2 45 45 Closest to 85th percentile speed
Per CA MUTCD Option 2,
rounded down to the
5 Alta Vista St Jefferson St Van Buren St 40 43.1 45 40 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
Chapman rounded down to the
6 Angelina Dr Ave Alta Vista St 35 37.5 40 35 nearest 5 mph increment below the 85th percentile
speed
7 Angelina Dr Morse Ave Palm Dr 35 34.7 35 35 Closest to 85th percentile speed
Bastanchury West City Kraemer Closest to 85th percentile 8 Rd Limit Blvd 45 45.3 45 45 speed
9 Bastanchury Kraemer Valencia Ave 45 45.5 45 45 Closest to 85th percentile Rd Blvd speed
Per CA MUTCD Option 2,
rounded down to the
Bastanchury East City
10 Rd Valencia Ave Limit 45 47.9 50 45 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
Bradford Chapman rounded down to the
11 Ave Santa Fe Ave Ave 25 27.7 30 25 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
Bradford Chapman rounded down to the
12 Ave Ave Madison Ave 30 34.3 35 30 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
Bradford North City rounded down to the
13 Ave Madison Ave Limit 35 38.1 40 35 nearest 5 mph increment below the 85th percentile
speed
2 Alta Vista St
Angelina Dr
Kraemer
Blvd
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No.
Street Name
From
to
Existing
Posted
Speed
Limit
(mph)
85th
Speed
(mph)
85th %
Speed
Rounded
(mph)
Recommended
Posted Speed
(mph)
Reason for Recommended
Speed Limit
Per CA MUTCD Option 2,
Brookhaven Yorba Linda Bastanchury rounded down to the
14 Ave Blvd Rd 30 33.4 35 30 nearest 5 mph increment
below the 85th percentile
speed
Buena Vista East City Closest to 85th percentile
15 Ave Rose Dr Limit 45 45.6 45 45 speed
16 Central Ave
ChaApmAveaAlta Vista St 40 40.6 40 40 Closest to 85thpercentile Per CA MUTCD Option 2,
Chapman Placentia Kraemer rounded down to the
17 Ave Ave Blvd 35 38.9 40 35 nearest 5 mph increment
below the 85th percentile
speed
Chapman Kraemer Orangethorpe Closest to 85th percentile 18Ave Blvd Ave 40 42.3 40 40 speed
19 Crowther Placentia porter Way 40 37.9 40 40 Closest to 85th percentile Ave Ave speed
Per CA MUTCD Option 2,
Crowther East City rounded down to the
20 Ave Porter Way Limit 45 48.6 50 45 nearest 5 mph increment below the 85th percentile
speed
South City North Closest to 85th percentile
21 Fee Ana St 35 36.5 35 35
Limit Terminus speed
Per CA MUTCD Option 2,
Kraemer rounded down to the
22 Golden Ave Blvd Valencia Ave 40 43.8 45 40 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
23 Golden Ave Valencia Ave East City 35 38.6 40 35 nearest 5 mph increment Limit
below the 85th percentile
speed
Highland Orangethorpe North City Closest to 85th percentile 24 Ave Ave Limit 30 30.9 30 30 speed
Per CA MUTCD Option 2,
Jefferson South City Orangethorpe rounded down to the
25 40 43.2 45 40 nearest 5 mph increment
Ave Limit Ave
below the 85th percentile
speed
26 Jefferson Orangethorpe Alta Vista St 40 39.0 40 40 Closest to 85th percentile Ave Ave speed
Per CA MUTCD Option 2,
Jefferson rounded down to the
27 Ave Alta Vista St Garten Dr 35 38.4 40 35 nearest 5 mph increment below the 85th percentile
speed
Kraemer South City Orangethorpe Closest to 85th percentile 28Blvd Limit Ave 40 42.3 40 40 speed
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Existing
Posted 85th %
No. Street Name From to Speed Speed
Limit (mph)
(mph)
29 Kraemer
Blvd
Kraemer
Blvd
Crowther
Ave
Chapman
Ave
Chapman
Ave
40 41.5
85th
Speed
Rounded
(mph)
40 Recommended
Posted Speed
(mph)
40 (3/13/2024)
Reason for Recommended
Speed Limit
Closest to 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
30 Fairway Lane 40 42.6 45 40 nearest 5 mph increment
below the 85th percentile
speed
Per CA MUTCD Option 2,
Kraemer Yorba Linda rounded down to the
31 Blvd Fairway Lane Blvd 40 42.8 45 40 nearest 5 mph increment below the 85th percentile
speed
Kraemer Yorba Linda Bastanchury Closest to 85th percentile 32Blvd Blvd Rd 45 44.6 45 45 speed
Per CA MUTCD Option 2,
rounded down to the
Kraemer Bastanchury North City
33 Blvd Rd Limit 40 43.6 45 40 nearest 5 mph increment
below the 85th percentile
speed
34 La Jolla St Placentia Closest to 85th percentile
Melrose St 30 30.2 30 30
Ave speed
Per CA MUTCD Option 2,
rounded down to the
East City
35 La Jolla St Melrose St 30 33.2 35 30 nearest 5 mph increment Limit
below the 85th percentile
speed
Per CA MUTCD Option 2,
Lakeview South City North City rounded down to the
36 45 48.8 50 45 nearest 5 mph increment
Ave Limit Limit
below the 85th percentile
speed
37 Linda Vista Rose Dr Yorba Linda 35 33.6 35 35 Closest to 85th percentile St Blvd speed
38 Livingston Clark Ave Kraemer 25 24.9 25 25 Closest to 85th percentile Ave Blvd speed
Per CA MUTCD Option 2,
rounded down to the
West City Kraemer
39 Madison Ave Limit Blvd 35 38.7 40 35 nearest 5 mph increment below the 85th percentile
speed
McCormack Yorba Linda North City Closest to 85th percentile 40 Lane Blvd Limit 30 29.6 30 30 speed
Per CA MUTCD Option 2,
rounded down to the
41 McCormack City Limit Golden Ave 30 33.3 35 30 nearest 5 mph increment Lane
below the 85th percentile
speed
Per CA MUTCD Option 2,
South City rounded down to the
42 Melrose St Limit La Jolla St 35 37.5 40 35 nearest 5 mph increment below the 85th percentile
speed
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Existing
Posted 85th %
No. Street Name From to Speed Speed
Limit (mph)
(mph)
85th %
Speed
Rounded
(mph)
Recommended
Posted Speed
(mph)
(3/13/2024)
Reason for Recommended
Speed Limit
Per CA MUTCD Option 2,
rounded down to the
43 Melrose St La Jolla St 35 38.9 40 35 nearest 5 mph increment below the 85th percentile
speed
44 Melrose St 40 40.7 40 40 Closest to 85th percentile
speed
Per CA MUTCD Option 2,
Crowther rounded down to the
45 Melrose St Ave Santa Fe Ave 30 32.8 35 30 nearest 5 mph increment below the 85th percentile
speed
Miraloma Lakeview Closest to 85th percentile
46 Van Buren St 35 35.5 35 35
Ave Ave speed
47 Morse Ave Kraemer Venice Ave 30 32.1 30 30 Closest to 85th percentile Blvd speed
Per CA MUTCD Option 2,
rounded down to the
48 Orangethorpe Placentia Melrose St 40 42.5 45 40 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
49 Orangethorpe Melrose St Kraemer 45 48.2 50 45 nearest 5 mph increment Ave Blvd
below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
50rounded downAve City Limit Rose Dr 45 49.1 50 45 nearest 5 mph increment below the 85th percentile
speed
51 Orangethorpe Rose Dr Lakeview 50 50.1 50 50 Closest to 85th percentile Ave Ave speed
Per CA MUTCD Option 2,
rounded down to the
52 Orchard Dr Van Buren St Richfield Rd 30 34.8 35 30 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
Highland rounded down to the
53 Orchard Dr Richfield Rd Ave 35 37.6 40 35 nearest 5 mph increment below the 85th percentile
speed
54 Orchard Dr Highland Lakeview 35 33.0 35 35 Closest to 85th percentile Ave Ave speed
Per CA MUTCD Option 2,
Yorba Linda rounded down to the
55 Palm Dr Blvd Valencia Ave 40 42.6 45 40 nearest 5 mph increment below the 85th percentile
speed
56 Palm Dr Valencia Ave Rose Dr 45 47.0 45 45 Closest to 85th percentile speed
Orangethorpe
Ave
Orangethorpe
Ave
Crowther
Ave
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Existing
Posted 85th %
No. Street Name From to Speed Speed
Limit (mph)
(mph)
Placentia
Ave
South City
Limit
85th
Speed
Rounded
(mph)
Recommended
Posted Speed
(mph)
(3/13/2024)
Reason for Recommended
Speed Limit
Per CA MUTCD Option 2,
rounded down to the
57 City Limit 40 43.6 45 40 nearest 5 mph increment
below the 85th percentile
speed
58 Placentia City Limit Rolling Hills 40 41.4 40 40 Closest to 85th percentile Ave Rd speed
Per CA MUTCD Option 2,
rounded down to the
59 Richfield Rd North City South City 45 48.4 50 45 nearest 5 mph increment Limit Limit
below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
60 Rose Dr OrangetAveorpe Alta Vista St 45 49.2 50 45 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
61 Rose Dr Alta Vista St Palm Dr 45 48.0 50 45 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
62 Rose Dr Palm Dr City Limit 40 43.6 45 40 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
North City rounded down to the
63 Rose Dr City Limit 40 43.2 45 40 nearest 5 mph increment Limit
below the 85th percentile
speed
64 Santa Fe Ave Placentia Closest to 85th percentile
Murray St 35 35.3 35 35
Ave speed
Per CA MUTCD Option 2,
Bradford rounded down to the
65 Santa Fe Ave Murray St Ave 25 27.9 30 25 nearest 5 mph increment below the 85th percentile
speed
Yorba Linda Closest to 85th percentile
66 Valencia Ave Palm Dr Blvd 40 40.4 40 40 speed
Per CA MUTCD Option 2,
rounded down to the
Yorba Linda Bastanchury
67 Valencia Ave Blvd Rd 40 43.4 45 40 nearest 5 mph increment below the 85th percentile
speed
Per CA MUTCD Option 2,
rounded down to the
68 Valencia Ave BastaBndChury Golden Ave 40 43.8 45 40 nearest 5 mph increment below the 85th percentile
speed
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Existing
Posted 85th
No. Street Name From to Speed Speed
Limit (mph)
(mph)
69 Valencia Ave
Golden Ave
North City
Limit
85th %
Speed
Rounded
(mph)
Recommended
Posted Speed
(mph)
(3/13/2024)
Reason for Recommended
Speed Limit
Per CA MUTCD Option 2,
rounded down to the
40 43.8 45 40 nearest 5 mph increment
below the 85th percentile
speed
South City Orangethorpe Closest to 85th percentile
70 Van Buren St 40 39.2 40 40
Limit Ave speed
71 Van Buren St Orangethorpe North City 40 41.8 40 40 Closest to 85th percentile Ave Limit speed
72 Yorba Linda Bradford City Limit 40 42.3 40 40 Closest to 85th percentile Blvd Ave speed
73 Yorba Linda City Limit Jefferson 40 41.2 40 40 Closest to 85th percentile Blvd Ave speed
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2.0 INTRODUCTION
2.1 Purpose and Need for E&TS
The intent of this E&TS is to establish and review prima facie speed limit zones set on certain public roadways within the jurisdiction of the City of Placentia (City), including any responsibilities assumed under such Memoranda of Understandings (MOUs) which may exist between the City and adjacent or overlapping agencies. The speeds to be established comply with the laws of the State of California as enacted by the State Legislature and Governor, and as generally codified within the California Vehicle Code (CVC). The E&TS review process represents a fair and defensible exercise of public policy. The E&TS provides the primary venue for agencies to satisfy the duty of the State and cities to provide for general health, welfare, and safety of its residents through an engineering study of vehicular speeds within the constructed public right of way, when those speeds are not otherwise set by statute.
Through this process, the E&TS goal is to obtain voluntary compliance in appropriately determined speed limits by gaining public confidence in a fair process, while also considering overall roadway safety with limited need for regular enforcement. All users of the roadway and transportation modes are considered in this process, including but not limited to pedestrian, bicycle, and equestrian. The E&TS also satisfies the requirements set forth in CVC 40802, which defines a "speed trap": a practice that is prohibited by State law whereby a speed limit is set arbitrarily low on streets other than streets classified as "local" streets. The E&TS, which is considered prima facie evidence in the prosecution of speed related violations, is used to refute a possible assertion by a potential violator that such a "speed trap" has been set by the agency. This E&TS meets the criteria set forth and establishes these local prima facie speed limits in compliance with CVC.
Local agencies should conduct engineering studies at least once every 5, 7 or 14 years, in compliance with CVC Section 40802 to reevaluate non -statutory speed limits on segments of their roadways that have undergone significant changes since the last review, such as the addition or elimination of parking or driveways, changes in the number of travel lanes changes in the configuration of bicycle lanes, changes in traffic control signal coordination, or significant changes in traffic volumes.
2.2 Study Locations
In coordination with the City of Placentia, it was determined that 73 segments were candidates for speed zone surveys.
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3.0 E&TS METHODOLOGY
3.1 State and Federal Regulations and Policies
3.1.1 California Vehicle Code (CVC)
CVC provides the legal framework for the establishment of regulatory speeds on all roadways in California. These regulatory speeds fall into three categories:
• State statutory speed limits (discussed in CVC 22349); generally, 65 mph upon a highway, and 55 mph upon a two-lane, undivided highway; not required to be posted to be enforceable • State prima facie speed limits established by statute (discussed in CVC 22352); generally, 15 mph for streets meeting certain criteria (e.g., traversing a railway grade crossing), and 25 mph for streets meeting certain criteria (e.g., a business or residence district, approaching a school building); generally must be posted to be enforceable
• Local prima facie speed limit zones (discussed in detail below); must always be posted to be enforceable
CVC provides cities and counties the ability to enact local prima facie speed limit zones within their jurisdictions. All speed limits must be set based on an engineering and traffic survey; otherwise, they may be considered a "speed trap". Per CVC 40802, a "speed trap", among other technical criteria for the measurement of speeds, is generally defined as follows:
40802. (a) A "speed trap" is either of the following:
(1) A particular section of a highway measured as to distance and with boundaries marked, designated, or otherwise determined in order that the speed of a vehicle may be calculated by securing the time it takes the vehicle to travel the known distance.
(2) A particular section of a highway with a prima facie speed limit that is provided by this code or by local ordinance under paragraph (1) of subdivision (b) of Section 22352, or established under Section 22354, 22357, 22358, or 22358,3, if that prima facie speed limit is not justified by an engineering and traffic survey conducted within five years prior to the date of the alleged violation, and enforcement of the speed limit involves the use of radar or any other electronic device that measures the speed of moving objects. This paragraph does not apply to a local street, road, or school zone, business activity district, or speed limit adopted under Section 22358.7 or 22358.8.
(b) (1) For purposes of this section, a local street or road is one that is functionally classified as "local" on the "California Road System Maps," that are approved by the Federal Highway Administration and maintained by the Department of Transportation. It may also be defined as a "local street or road" if it primarily provides access to abutting residential property and meets the following three conditions:
(A) Roadway width of not more than 40 feet.
(B) Not more than one-half of a mile of uninterrupted length. Interruptions shall include official traffic control signals as defined in Section 445.
(C) Not more than one traffic lane in each direction.
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CVC 22357 and 22358 outline the corresponding options for applying state statute prima facie speed limits or establishing local prima facie speed limit zones:
22357. (a) Whenever a local authority determines upon the basis of an engineering and traffic survey that a speed greater than 25 miles per hour would facilitate the orderly movement of vehicular traffic and would be reasonable and safe upon any street other than a state highway otherwise subject to a prima facie limit of 25 miles per hour, the local authority may by ordinance determine and declare a prima facie speed limit of 30, 35, 40, 45, 50, 55, or 60 miles per hour or a maximum speed limit of 65 miles per hour, whichever is found most appropriate to facilitate the orderly movement of traffic and is reasonable and safe. The declared prima facie or maximum speed limit shall be effective when appropriate signs giving notice thereof are erected upon the street and shall not thereafter be revised except upon the basis of an engineering and traffic survey. This section does not apply to any 25 -mile -per -hour prima facie limit which is applicable when passing a school building or the grounds thereof or when passing a senior center or other facility primarily used by senior citizens.
22358. (a) Whenever a local authority determines upon the basis of an engineering and traffic survey that the limit of 65 miles per hour is more than is reasonable or safe upon any portion of any street other than a state highway where the limit of 65 miles per hour is applicable, the local authority may by ordinance determine and declare a prima facie speed limit of 60, 55, 50, 45, 40, 35, 30, 25, 20 or 15 miles per hour, whichever is found most appropriate to facilitate the orderly movement of traffic and is reasonable and safe, which declared prima facie limit shall be effective when appropriate signs giving notice thereof are erected upon the street.
22358.3. Whenever a local authority determines upon the basis of an engineering and traffic survey that the prima facie speed limit of 25 miles per hour in a business or residence district or in a public park on any street having a roadway not exceeding 25 feet in width, other than a state highway, is more than is reasonable or safe, the local authority may, by ordinance or resolution, determine and declare a prima facie speed limit of 20 or 15 miles per hour, whichever is found most appropriate and is reasonable and safe. The declared prima facie limit shall be effective when appropriate signs giving notice thereof are erected upon the street. 22358.4. (a) (1) Whenever a local authority determines upon the basis of an engineering and traffic survey that the prima facie speed limit of 25 miles per hour established by subdivision (b) of Section 22352 is more than is reasonable or safe, the local authority may, by ordinance or resolution, determine and declare a prima facie speed limit of 20 or 15 miles per hour, whichever is justified as the appropriate speed limit by that survey.
(2) An ordinance or resolution adopted under paragraph (1) shall not be effective until appropriate signs giving notice of the speed limit are erected upon the highway and, in the case of a state highway, until the ordinance is approved by the Department of Transportation and the appropriate signs are erected upon the highway.
CVC defines an Engineering and Traffic Survey. Per CVC 627:
627. (a) "Engineering and traffic survey," as used in this code, means a survey of highway and traffic conditions in accordance with methods determined by the Department of Transportation for use by state and local authorities.
(b) 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.
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(2) Accident records,
(3) Highway, traffic, and roadside conditions not readily apparent to the driver. (c) When conducting an engineering and traffic survey, local authorities, in addition to the factors set forth in paragraphs (1) to (3), inclusive, of subdivision (b) may consider all of the following:
(1) Residential density, if any of the following conditions exist on the particular portion of highway and the property contiguous thereto, other than a business district:
(A) Upon one side of the highway, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 13 or more separate dwelling houses or business structures.
(B) Upon both sides of the highway, collectively, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 16 or more separate dwelling houses or business structures.
(C) The portion of highway is longer than one-quarter of a mile but has the ratio of separate dwelling houses or business structures to the length of the highway described in either subparagraph (A) or (B).
(2) Safety of bicyclists and pedestrians, with increased consideration for vulnerable pedestrian groups including children, seniors, persons with disabilities, users of personal assistive mobility devices, and the unhoused.
Furthermore, CVC 22358.6 establishes how speed limits may be rounded to the nearest 5 mph increment of the 85th percentile speed measured as part of the E&TS 22358.6. (a) The Department of Transportation shall, in the next scheduled revision, revise and thereafter maintain the California Manual on Uniform Traffic Control Devices to require the Department of Transportation or a local authority to round speed limits to the nearest five miles per hour of the 85th percentile of the free-flowing traffic.
(b) In cases in which the speed limit needs to be rounded down to the nearest five miles per hour increment of the 85th -percentile speed, the Department of Transportation or a local authority may lower the speed limit by five miles per hour from the nearest five mile per hour increment of the 85th -percentile speed, in compliance with Sections 627 and 22358.5 and the California Manual on Uniform Traffic Control Devices, as it read on March 30, 2021, if the reasons for the lower speed limit are documented in an engineering and traffic survey. The Department of Transportation or a local authority may also take into consideration Sections 22353, 22353.2, 22353.3, 22353.4, and 22353.5, if applicable. (c) In cases in which the speed limit needs to be rounded up to the nearest five miles per hour increment of the 85th -percentile speed, the Department of Transportation or a local authority may decide to instead round down the speed limit to the lower five miles per hour increment. If the speed limit is rounded down pursuant to this subdivision, the speed limit shall not be reduced any further pursuant to subdivision (b). (d) In addition to subdivisions (b) and (c), a local authority may additionally lower the speed limit as provided in Section 22358.7.
(e) The total reduction in the speed limit pursuant to subdivisions (a) to (d), inclusive, shall not exceed 12.4 miles per hour from the 85th percentile speed.
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(t) Notwithstanding subdivisions (a) to (e), inclusive, a local authority may retain the currently adopted speed limit as provided in Section 22358.8 without further reduction, or restore the immediately prior adopted speed limit as provided in Section 22358.8 without further reduction.
To prevent overuse of speed zoning practices by using CVC 627(b)(3) as justification to lower a prevailing speed, CVC 22358.5 requires that only conditions which may not be readily apparent to the driver can be used as justification for speed reduction.
22358.5. It is the intent of the Legislature that physical conditions such as width, curvature, grade and surface conditions, or any other condition readily apparent to a driver, in the absence of other factors, would not require special downward speed zoning, as the basic rule of section 22350 is sufficient regulation as to such conditions.
3.1.2 California Manual on Uniform Traffic Control Devices (CA MUTCD) The California MUTCD provides guidance on the application of the E&TS defined in CVC, including a refined procedure for evaluation of local prima facie speed limit zones. The first step is to obtain prevailing speeds using 85th percentile spot speed measurements. Next, the 85th percentile measurements are rounded to the nearest 5 -mph increment, except as shown in the two Options below:
• Option 1: For cases in which the nearest 5 mph increment of the 85th -percentile speed would require a rounding down, the posted speed may be reduced by 5 mph from the nearest 5 mph increment of the 85th -percentile speed, in compliance with CVC Sections 627 and 22358.5. CVC Sections 22353, 22353.2, 22353.3, 22353.4, and 22353.5, may also be considered, if applicable.
See Standard below for documentation requirements. Refer to CVC Section 22358.6(b). • Option 2: For cases in which the nearest 5 mph increment of the 85th -percentile speed would require a rounding up, then the speed limit may be rounded down to the nearest 5 mph increment below the 85th -percentile speed, if no further reduction is used. Refer to CVC 22358.6(c).
The California MUTCD Section 26.13 states the following about the measurement of prevailing speeds:
Prevailing speeds are determined by a speed zone survey. A speed zone survey should include:
A. The intent of the speed measurements is to determine the actual speed of unimpeded traffic. The speed of traffic should not be altered by concentrated law enforcement, or other means, just prior to, or while taking the speed measurements.
B. Only one person is required for the field work. Speeds should be read directly from a radar or other electronic speed measuring devices; or,
C. Devices, other than radar, capable of accurately distinguishing and measuring the unimpeded speed of free flowing vehicles may be used.
D. A location should be selected where prevailing speeds are representative of the entire speed zone section. If speeds vary on a given route, more than one speed zone section may be required, with separate measurements for each section. Locations for measurements should be chosen so as to minimize the effects of traffic signals or stop signs.
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E. Speed measurements should be taken during off-peak hours between peak traffic periods on weekdays.
If there is difficulty in obtaining the desired quantity, speed measurements may be taken during any period with fee flowing traffic.
F. The weather should be fair (dry pavement) with no unusual conditions prevailing.
G. The surveyor and equipment should not affect the traffic speeds. For this reason, an unmarked car is recommended, and the radar speed meter located as inconspicuously as possible.
H. In order for the sample to be representative of the actual traffic flow, the minimum sample should be 100 vehicles in each survey. In no case should the sample contain less than 50 vehicles.
I. Short speed zones of less than 0.5 miles should be avoided, except in transition areas.
J. Speed zone changes should be coordinated with changes in roadway conditions or roadside development.
K. Speed zoning should be in 10 mph increments except in urban areas where 5 mph increments are preferable.
L. Speed zoning should be coordinated with adjacent jurisdictions.
The California MUTCD Section 2B.13 provides Options about other factors to consider that may not be apparent to the driver, in compliance with CVC 22358.5 (line 16 and line 30, Section 2a):
Other factors that may be considered when establishing or reevaluating speed limits are the following:
A. Road characteristics, shoulder condition, grade, alignment, and sight distance;
8. The pace;
C. Roadside development and environment;
D. Parking practices and pedestrian activity; and
E. Reported crash experience for at least a 12 -month period.
2. City and County Through Highways, Arterials, Collector Roads and Local Streets a. The short method of speed zoning is based on the premise that a reasonable speed limit is one that conforms to the actual behavior of the majority of motorists, and that by measuring motorists' speeds, one will be able to select a speed limit that is both reasonable and effective.
Other factors that need to be considered include but are not limited to: the most recent two-year collision record, roadway design speed, safe stopping sight distance, superelevation, shoulder conditions, profile conditions, intersection spacing and offsets, commercial driveway characteristics, and pedestrian traffic in the roadway without sidewalks.
3.1.3 Previous Studies
Caltrans Division of Traffic Operation has published a manual on a uniform procedure for setting speed limits in California. The manual titled "California Manual for Setting Speed Limits 2020" coincides with the guidelines outlined in the California MUTCD and is based upon statutes published in the CVC. The 85th percentile used in an E&TS is defined and justified as follows:
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Speed limits set by E&TS are normally set near the 85th percentile speed. The 85th percentile speed is the speed at or below which 85 percent of the traffic is moving, and statistically represents one standard deviation above the average speed.
Studies of the effects of establishing, raising and lowering speed limits include federal studies FHWA-RD-92- 084 and FHWA-RD-98-154 (summaries can be found in Appendix D.1 and the full reports can be found at the FHWA web site). These studies demonstrate that the most effective attribute in establishing the speed limit is to determine the 85th percentile speed and set the posted speed close to that value. The empirical data in these studies demonstrates that setting the speed limit too high or too low can increase collisions. Speed limits that are set near the 85th percentile speed of free flowing traffic are safer and produce less variance in vehicle speeds. Because of this, the 85th percentile is used to establish the upper limit of operating speeds that are considered reasonable and prudent.
3.2.6 Calculating 85th Percentile Speed
If 100 vehicle speeds are plotted, the 85th percentile speed is determined by looking at the speed of the 15th vehicle down from the top speed. Fifteen percent of the vehicles are travelling faster than this speed, and eighty five percent are travelling of or below this speed. If less than 100 vehicles are counted, the 85th percentile speed must be determined by calculating 85 percent of the number of vehicles counted and determining the vehicles' 85th percentile speed.
3.4.1 Zone Length
The length of any section of roadway set for a particular speed zone should be as long as possible and consistent with changes in roadway conditions, roadside development, and land use. Speed zone or speed limit changes need to be coordinated with changes in roadway conditions, roadside development, and land use. Speed zones of less than 0.5 miles should be avoided. Create separate speed zones at City, County or other jurisdictional boundaries with a consistent speed limit across the boundary.
The Federal Highway Administration published a review entitled Synthesis of Safety Research Related to Speed and Speed Management, Publication Number: FHWA-RD-98-154 (July 1998). This publication built on a similar synthesis developed in 1982. The synthesis highlights the relationships among vehicle speed and safety; factors influencing speeds; and the effects on speed and crashes of speed limits, speed enforcement, traffic calming and other engineering measures intended to manage speed.
The review defined the 10 -mph pace as the speed range that contains the largest percentage of vehicles.
Crash history was also discussed in relation to prevailing speeds:
There is evidence that crash risk is lowest near the average speed of traffic and increases for vehicles traveling much faster or slower than average.
When the consequences of crashes are taken into account, the risk of being involved in an injury crash is lowest for vehicles that travel near the median speed or slower and increases exponentially for motorists traveling much faster.
In general, changing speed limits on low and moderate speed roads appears to have little or no effect on speed and thus little or no effect on crashes. This suggests that drivers travel at speeds that they feel are reasonable and safe for the road and traffic regardless of the posted limit.
The Federal Highway Administration also published a report entitled "Effects of Raising and Lowering Speed Limits, Publication Number: FHWA-RD-92-084 (October 1992)". This report determined the LIN Consulting, Inc. Page) 14
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succeeding effects of raising and lowering posted speed limits on driver behavior and accidents. The following conclusion further illustrates the importance of conducting engineering investigations to consider prevailing speed, vehicle pace, and crash history to establish reasonable speed limits:
In other words, this nationwide study confirms the results of numerous other observational studies which found that the majority or motorist do not alter their speed to conform to speed limits they perceives as unreasonable for prevailing conditions.
Because there were few changes in the speed distribution, it is not surprising that the overall effects of speed limit changes on accidents were minor. It is interesting to note that compliance decreased when speed limits were lowered and accidents tended to increase. Conversely, when compliance improved after speed limits were raised, accidents tended to decrease.
The data collected during this study indicate that there are no benefits, either from a safety or operational point of view, from establishing speed limits less than the 85th percentile speed. This does not mean that all speed limits should be raised. Traffic and engineer investigations should be conducted to obtain an accurate measure of the speed distribution. Greater emphasis should be placed on using the 85th percentile speed in setting safe and reasonable speed limits. These studies should be repeated as land use and traffic characteristics change.
On December 19, 2023, a final rule adopting the 11th Edition of the Manual on Uniform Traffic Control Devices for Streets and Highways—the MUTCD—was published in the Federal Register. The new MUTCD puts less emphasis on 85th percentile rule but does not eliminate it. Section 28.21 states:
08 When the 85th -percentile speed is appreciably greater than the posted speed limit, and the roadway context does not support setting a higher speed limit, the engineering study should consider whether changes to geometric features, enforcement, and/or other speed -reduction countermeasures might improve compliance with the posted speed limit. A similar approach should be used if the results of past speed studies indicate that the 85th -percentile speed has consistently increased. 09 On urban and suburban arterials, and on rural arterials that serve as main streets through developed areas of communities, the 85th -percentile speed should not be used to set speed limits without consideration of all factors described in Paragraph 7 of this Section.
California will have a 2 -year period through January 18, 2026, to have a revised CA MUTCD in substantial conformance with the National MUTCD. California will continue to use the CA MUTCD 2014 Revision 8 until it is replaced with a newer version.
3.2 Data Collection
Data for the prevailing speed of vehicles, average daily traffic and traffic collisions were collected for the 73 speed zones.
3.2.1 Speed Survey
Aim Traffic Data (AimTD), a professional traffic data collection firm, conducted spot speed measurements at the E&TS locations from September 26, 2023 to November 14, 2023. The speed measurements at the E&TS locations were conducted using two calibrated radar devices, by two certified Radar Operators (Olga Polunin and Javier Correa). These devices directly measure the speed of vehicles and are LIN Consulting, Inc. Page 15
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commonly used for spot speed measurements. A copy of the most recent certification of the radar equipment used is included in Appendix A.
To obtain free flowing (unimpeded) speeds at the study locations, the radar speed measurement procedure was conducted on a clear day during the non -peak hour period. The manual speed measurement procedure was conducted until at least 100 vehicles were surveyed at the study locations, or one hour for locations with low volumes. When possible, sample locations were outside of the influence area of stop signs or traffic signals.
The speed surveys provide 85th percentile speeds, the 50th percentile, the percent in pace, and vehicle 10 -mph pace. The detailed results from the speed sampling procedure are attached in Appendix B.
3.2.2 Average Daily Traffic
AimTD collected 24-hour volume counts at each speed zone to provide measures of Average Daily Traffic (ADT) from December 6, 2023 to January 9, 2024. The ADT data is provided in Table 3-1 and the detailed counts are provided in Appendix C.
3.2.3 Crash Data Calculation
City provided the 5 -year collision summaries for all the streets throughout the City. This information was used in determining the crash rate in millions of vehicle miles (MVM). Since the crash data information was provided for each street and not for each speed zone, crash rates were calculated based on the highest ADT for the street when there are multiple speed zones on the same street.
The crash rate for each speed zone was calculated using the following formula:
Crash Rate per Year = Highest ADT x Length of segment of the street(mi) x 365 days per year x 5 years Number of crashes of the street in 5 years x 1,000,000
The crash rates for speed zones in Placentia are provided in Table 3-1 and the details are provided in Appendix D.
Statewide statistics for functional roadway classifications are provided and were obtained from the Caltrans websites for the 2021 reporting period. Crash rates on roadways that are higher than the statewide average are an indicator that a condition that is not readily apparent to the driver may exist on that particular segment.
1 https://dot.ca.govHmedia/dot-media/programs/research-innovation-system-information/documents/annual-collision- data/2021crashdataoncshwybooklally.pdf (accessed 1/25/24) LIN Consulting, Inc. Page 116
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Table 3-1. 2024 Average Daily Traffic and Crash Rate Calculation Street Name
All America
Way
2 Alta Vista St
3 Alta Vista St
4 Alta Vista St
5 Alta Vista St
6 Angelina Dr
7 Angelina Dr
Bastanchury
Rd
Bastanchury
Rd
Bastanchury
Rd
11 Bradford Ave
12 Bradford Ave
13 Bradford Ave
Brookhaven
Ave
Buena Vista
Ave
16 Central Ave
17 Chapman Ave
8 9
10 14
15 (3/13/2024)
From
to
Average Daily
Traffic
5 -Year
Total
Collision
by
Roadway
Se . ment
Crash Rate
for Each
Roadway
Segment
(MVM)1
Alta Vista St
Angelina Dr
Kraemer Blvd
Rose Dr
Jefferson St
Chapman Ave
Morse Ave
West City Limit
Kraemer Blvd
Valencia Ave
Santa Fe Ave
Chapman Ave
Madison Ave
Yorba Linda
Blvd
Rose Dr
Chapman Ave
Placentia Ave
18 Chapman Ave Kraemer Blvd
19 Crowther Ave
20 Crowther Ave
21 Fee Ana St
22 Golden Ave
23 Golden Ave
24 25
I 26
Highland Ave
Jefferson Ave
Jefferson Ave
27 Jefferson Ave
Placentia Ave
Porter Way
South City Limit
Kraemer Blvd
Valencia Ave
Orangethorpe
Ave
South City Limit
Orangethorpe
Ave
Alta Vista St
28 Kraemer Blvd South City Limit
29 Kraemer Blvd
30 Kraemer Blvd
Crowther Ave
Chapman Ave
31 Kraemer Blvd Fairway Lane
Chapman Ave
Kraemer Blvd
Rose Dr
Jefferson St
Van Buren St
Alta Vista St
Palm Dr
Kraemer Blvd
Valencia Ave
1,259
3,518
11,767
8,075
4,546
2,299
2,538
24,664
20,195
East City Limit 16,307
Chapman Ave
Madison Ave
North City Limit
Bastanchury Rd
East City Limit
Alta Vista St
Kraemer Blvd
Orangethorpe
Ave
Porter Way
East City Limit
North Terminus
Valencia Ave
East City Limit
North City Limit
Orangethorpe
Ave
Alta Vista St
Garten Dr
Orangethorpe
Ave
Chapman Ave
Fairway Lane
Yorba Linda
Blvd
4,209
7,387
9,418
1,617
8,705
2,824
15,848
6,847
5,517
4,747
2,063
5,005
3,967
1,163
3,374
3,139
754
20,353
19,000
18,962
21,279
0 40
18 80
0.00 0.95
6.82 0.88
59 2.27
2 1.36
7 0.44
4 2.28
123 2.27
10 0.91
1 0.38
11 1.10
4 5.09
18 113
3.40 1.02
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No.
Street Name
32 Kraemer Blvd
33 Kraemer Blvd
34 La Jolla St
35 La Jolla St
36 Lakeview Ave
37 Linda Vista St
38 Livingston Ave
39 Madison Ave
McCormack
Lane
McCormack
Lane
Melrose St
40 41
42 43
44 Melrose St
Melrose St
45 Melrose St
46 Miraloma Ave
47 Morse Ave
Orangethorpe
Ave
Orangethorpe
Ave
Orangethorpe
Ave
Orangethorpe
Ave
52 Orchard Dr
53 Orchard Dr
54 Orchard Dr
48 49
50 51
55 Palm Dr
56 Palm Dr
57 Placentia Ave
58 Placentia Ave
59 Richfield Rd
From
Yorba Linda
Blvd
Bastanchury Rd
Placentia Ave
Melrose St
South City Limit
Rose Dr
Clark Ave
West City Limit
Yorba Linda
Blvd
City Limit
South City Limit
La Jolla St
Orangethorpe
Ave
Crowther Ave
Van Buren St
Kraemer Blvd
Placentia Ave
Melrose St
City Limit
Rose Dr
Van Buren St
Richfield Rd
Highland Ave
Yorba Linda
Blvd
Valencia Ave
South City Limit
City Limit
North City Limit
to
Bastanchury Rd
North City Limit
Melrose St
East City Limit
North City Limit
Yorba Linda
Blvd
Kraemer Blvd
Kraemer Blvd
North City Limit
Golden Ave
La Jolla St
Orangethorpe
Ave
Crowther Ave
Santa Fe Ave
Lakeview Ave
Venice Ave
Melrose St
Kraemer Blvd
Rose Dr
Lakeview Ave
Richfield Rd
Highland Ave
Lakeview Ave
Valencia Ave
Rose Dr
City Limit
Rolling Hills Rd
South City Limit
Average Daily
Traffic
18,436
16,467
5,994
4,664
14,439
1,627
864
6,737
1,697
781
11,085
13,271
8,636
6,375
4,702
1,256
18,725
18,700
16,087
16,146
2,989
3,332
2,417
8,534
10,356
15,766
18,715
7,846
5 -Year
Total
Collision
by
Roadway
Se . ment
35 8
12 1
5 12
45 9
5 172
9 27
166
10 (3/13/2024)
Crash Rate
for Each
Roadway
Segment
(MVM)'
3.72 0.76
14.43 1.32
0.67 3.87
2.11 2.69
3.46 1.67
1.85 1.28
1.87 0.87
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No.
Street Name
From
to
Average Daily
Traffic
5 -Year
Total
Collision
by
Roadway
Segment
Crash Rate
for Each
Roadway
Segment
(MVM)'
60 Rose Dr
61 Rose Dr
62 Rose Dr
63 Rose Dr
64 Santa Fe Ave
65 Santa Fe Ave
66 Valencia Ave
67 Valencia Ave
68 Valencia Ave
69 Valencia Ave
70 Van Buren St
71 Van Buren St
72 Yorba Linda
Blvd
73 Yorba Linda
Blvd
Orangethorpe
Ave
Alta Vista St
Palm Dr
City Limit
Placentia Ave
Murray St
Palm Dr
Yorba Linda
Blvd
Bastanchury Rd
Golden Ave
South City Limit
Orangethorpe
Ave
Bradford Ave
City Limit
Alta Vista St
Palm Dr
City Limit
North City Limit
Murray St
Bradford Ave
Yorba Linda
Blvd
23,957
31,583
19,875
21,087
2,790
2,952
6,211
Bastanchury Rd 10,228
Golden Ave
North City Limit
Orangethorpe
Ave
9,229
7,899
4,352
North City Limit 4,352
City Limit 22,313
Jefferson Ave 21,687
' Crash rate was calculated based on the highest average daily traffic volumes of multiple speed zones. 88 20
33 24
123
0.77 7.00
1.24 3.51
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4.0 CONCLUSIONS
In 2013, an E&TS was conducted for the City of Placentia. These speed zone recommendations were then used to set local prima facie speed zones and speed limits by ordinance of the City Council.
This E&TS confirms that the speed zones established in 2013 are still appropriate and should remain in effect. An E&TS sheet for each speed zone is provided in Appendix E. A complete summary of all recommendations was shown above in Table 1-1.
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