California Manual for Setting Speed Limits

1 2020 Division of traffic Operations California Department of Transportation Copyright 2020 California Department of Transportation. All Rights Reserved. California Manual for Setting Speed Limits (Revised February 2020) California Manual for Setting Speed Limits Disclaimer This Manual ( Manual ) does not constitute a standard, specification, or regulation. This Manual is not intended to replace the existing Caltrans mandatory or advisory standards and is not intended to be a substitute for engineering knowledge, experience or judgment. This Manual promotes better access to helpful information and concepts from various agencies and organizations. Caltrans acknowledges the existence of other practices and provides this Manual for reference and direction for those responsible for making professional engineering or other design decisions.

2 Please be aware that Caltrans is not the author of the external sources contained in this Manual and is therefore not responsible for errors or omissions that may be contained within those external sources. The references contained in this Manual are provided for the user s convenience. The content or information in such references is the sole responsibility of their respective authors and/or owners. Copyright 2020 California Department of Transportation. All Rights Reserved. Page 1 California Manual for Setting Speed Limits This page has intentionally been left blank. Page 2 Copyright 2020 California Department of Transportation. All Rights Reserved. California Manual for Setting Speed Limits California Manual for Setting Speed Limits Division of traffic Operations California Department of Transportation 2020 Copyright 2020 California Department of Transportation.

3 All Rights Reserved. Page 3 California Manual for Setting Speed Limits This page has intentionally been left blank. Page 4 Copyright 2020 California Department of Transportation. All Rights Reserved. California Manual for Setting Speed Limits Table of Contents CHAPTER 1 Purpose of this Manual ..11 Users of this General Basic Speed Prima Facie Speed Limits by Speed Limits Requiring an Engineering and Authority to Set Speed Speed Factors Affecting Drivers Design and Physical Characteristics of the The The traffic ..15 Weather and Visibility ..15 Other Roadway Users ..15 Vehicle Operating CHAPTER 2 REGULATORY AND ADVISORY Regulatory Speed Zones Established by an Engineering and traffic Regulatory Highway Approaches to Incorporated Municipalities.

4 18 Minimum Speeds ..18 Signs within Cities and Advisory Speeds ..19 Regulatory Versus Advisory Advisory Speeds in Regulatory Speed temporary traffic Control Advisory and Regulatory Advisory temporary traffic Control Speeds ..21 temporary traffic Control Speed Limit in Construction Work Zones ..21 Copyright 2020 California Department of Transportation. All Rights Reserved. Page 5 California Manual for Setting Speed Limits Request for Maintenance Regulatory temporary traffic Control Speed Zones.

5 25 Signs Installed by the School Speed Planning for School Areas ..26 School Zones under Local Signs for School Intervals of Operation ..27 Reduced Truck Speed Limit on Descending Grades ..28 Private Roads ..29 Variable Speed Setting a Speed Limit at 70 Special Weather Chapter 3 ENGINEERING AND traffic SURVEYS (E&TS)..32 Scope of Survey ..32 Components of an E&TS ..32 Data Collection and Location of Speed Selecting Vehicles Under Free Flow Measuring Vehicle Recording Measured Calculating 85th Percentile Collision Evaluating Existing Conditions ..36 Developing Strip Maps ..37 Strip Map Example ..37 Scale for Strip Information to Include on the Strip Speed Zone Design.

6 38 Zone Length ..38 Directional Variation from the 85th Applying a 5 Mile Per Hour Reduction ..39 Trial Page 6 Copyright 2020 California Department of Transportation. All Rights Reserved. California Manual for Setting Speed Limits CHAPTER 4 LOCATION OF REGULATORY Speed LIMIT SIGNS ..41 Speed Limit: R2-1 ..41 Speed Zone Ahead: R2-4 (CA)..42 End Speed Limit: R3 (CA)..43 Speed Limit, Trucks, & All Vehicles When Towing: R2-1, R6-3 (CA) and R6-4 (CA).

7 43 Special Enforcement Signs ..44 Speed Enforced By Radar: R48 (CA) ..44 Radar Enforced: R48-1(CA)..44 Speed Enforced By Aircraft: R48-2(CA)..44 CHAPTER 5 RENEWAL OF E&TS Frequency of Rechecks ..45 Procedure for 7 to 10 Year Extensions ..46 Renewal before CHAPTER 6 Speed ZONE APPROVAL AND Differences between State and Local Approval Process ..47 Consultation with local California Highway Patrol and Other Agencies ..47 Local Government Notification and Public Attend Public Reassess Proposed Speed Limit Prepare New Speed Zone Orders ..48 Determine Need for New Advisory Speed Determine Need for Signal Loop Detection to be Adjusted ..48 Determine Need for Yellow Change Interval Timing to be Adjusted.

8 48 Study Completion ..48 Transmittal Sign Installation Orders ..49 Regular Public Request ..49 Appendix A Example Vehicle Speed Survey Sheet Count Less Than Vehicle Speed Survey Sheet Count Greater Than Copyright 2020 California Department of Transportation. All Rights Reserved. Page 7 California Manual for Setting Speed Limits Vehicle Speed Survey Sample Strip Table : California Manual for Uniform traffic Control Devices guidelines for Advance Placement of Warning Sample TSAR Report: Collision Summary.

9 57 TSAR Detail Example Table B Regulatory Speed Zone Sign Transition Zones ..63 Appendix B Sample Sample Request for temporary traffic Control Speed - Construction Work Zone Speed Limit Reduction Determination Form CEM 1301 (NEW XX/XX/2020) ..66 Sample Notification to Board of Supervisors/Public Hearing ..69 Sample Order 1: Decreasing 55mph Speed Limit on State Highway ..70 Sample Order 2: Increasing 65mph Speed Limit on State Sample Transmittal Memo to Deputy Sample Transmittal Letter to California Highway Sample Cover Letter for Speed Survey to Public Person(s)..74 Sample Response Letter for Non-E&TS Area ..75 Justification Memo Sample Justification Memo Sample Letter to CHP Extending Survey to 10 Years.

10 79 Appendix C Appendix D Federal Studies PUBLICATION NO. FHWA-RD-98-154 July 1998 ..86 Report No. FHWA-RD-92-084 October Missouri Department of Transportation Study RI08-025 ..88 California Department of Motor Vehicles Driver Hand Automobile Club of Southern Institute of Transportation Transportation Research California Manual on Uniform traffic Control Devices ..88 Appendix E California Vehicle Code Page 8 Copyright 2020 California Department of Transportation. All Rights Reserved. 18 .27 ..29 California Manual for Setting Speed Limits Index of FiguresFigure 2-1: Speed Limit Figure 2 -2: Reduced Speed Ahead Advisory 2 -3: Advisory Figure 2 -4: temporary traffic Control Advisory Figure 2 -5: TTC Regulatory Figure 2 -6: Signs for School 2 -7: Truck Plaque with Speed Limit 2-8: Chain Control 31 Figure 3-1: The Cosine 33 Figure 4-1: Speed Limit 42 Figure 4-2: Reduced Speed Zone Ahead.