Traffic Analysis



PROJECT TITLE

One sentence description of proposed project

TRAFFIC IMPACT STUDY

Prepared in Accordance With

Chapter 5 of the NYSDOT Highway Design Manual (HDM)

Prepared By:

[Regional Design Group] or [Consulting Firm]

[NYSDOT Region] or [Consultant Location]

Date (Month and Year)

|PLACE P.E. STAMP |

Note: It is a violation of law for any person, unless they are acting under the direction of a licensed professional engineer, architect, landscape architect, or land surveyor, to alter an item in any way. If an item bearing the stamp of a licensed professional is altered, the altering engineer, architect, landscape architect, or land surveyor shall stamp the document and include the notation "altered by" followed by their signature, the date of such alteration, and a specific description of the alteration.

This report is based on the NYSDOT TIS Shell revised on 5/16/2014.

Table of Contents

1.0 SUMMARY OF TRAFFIC IMPACTS 3

2.0 TRAVEL SPEEDS 3

3.0 CAPACITY ANALYSIS 3

3.1 Growth Rates 5

3.2 Existing Volumes 5

3.3 Projected Trip Generation 5

3.4 Internal Circulation & Parking 6

3.5 Traffic Control Device Data 6

3.6 Capacity Analysis for Existing Condition 6

3.7 Capacity Analysis for Proposed Condition 7

3.8 Mitigation Measures 7

4.0 CRASH ANALYSIS 8

4.1 Existing Crash Data 8

4.2 Analysis of Crash Data 8

4.3 Compare Rates to Accepted Values 9

4.4 Mitigation Measures 9

APPENDICIES 11

A Volume Report 11

B Existing Condition Capacity Analysis Output 12

C Proposed Condition Capacity Analysis Output 13

D Crash Analysis Diagrams/Tables (Major Commercial Only) 14

1.0 Summary of Traffic Impacts

Refer to Exhibits 5D-5 through 5D-7 in the NYSDOT Highway Design Manual, Chapter 5, Appendix D. The designer should reference the graph that best represents the existing highway configuration. The project will fall under one of the following conditions. Include one of the following statements:

A. [A capacity analysis was performed per NYSDOT Highway Design Manual Chapter 5. The following mitigation measures are recommended to maintain the existing no-build level of service and delays: __________________. Refer to Section 3 of this report]

B. [The proposed development will maintain an acceptable Level of Service according to Section 3.0 of this report.]

The project will fall under one of the following conditions. Include one of the following statements:

C. [There are High Accident Locations (HAL’s) within 0.1 miles of the proposed driveway. A crash analysis was performed per Highway Design Manual Chapter 5. The following mitigation measures will be included to reduce the frequency and severity of crashes: __________.] Refer to Section 4 of this report.

D. [There are no High Accident Locations (HAL’s) within 0.1 miles of the proposed driveway. A crash analysis is not required.]

2.0 Travel Speeds

The posted speed limit and the off-peak 85th percentile speed determined based on NYSDOT Highway Design Manual Chapter 5, Section 5.2 are shown in the table below.

Identify the existing travel speeds on the segments of interest (85th percentile speeds are used for Work Zone Traffic Control and for capacity analysis). If multiple roads are being analyzed, present the data in a table. Show the:

1) Existing Speed Limit

2) Actual Operating Speed (from NYSDOT Traffic Data Viewer or a speed study)



|Exhibit 1 |

|Speed Data |

|Street Name |Limits |Posted Speed |Actual Operating Speed |

| |(From – To) | | |

|SR 14 |Main Street to 5th Street |55 mph |52.4 mph |

|CR 72 |SR 14 to Jay Street |45 mph |49.8 mph |

3.0 Capacity Analysis

Refer to Exhibits 5D-5 through 5D-7 in the NYSDOT Highway Design Manual, Chapter 5, Appendix D. The designer should reference the graph that best represents the existing highway configuration. The project will fall under one of the following conditions. Include one of the following statements:

A. [Traffic conditions at the proposed driveway fall within the L.O.S. “E or Worse” zone for urban highways; or the L.O.S. “D” or “E or Worse” zones for rural highways. A capacity analysis is required.]

B. [Traffic conditions at the proposed driveway fall within the L.O.S. “C or Better” or “D” zone for urban highways; or the L.O.S. “C or Better” zone for rural highways. Further capacity analysis is not required.] (Designer should omit Sections 3 of this report, and continue with Section 4)

Capacity Analysis Overview

Capacity analyses performed in this report are consistent with the most recent version of the Highway Capacity Manual (HCM). The software used to perform this analysis is [VISSIM, Synchro-Sim Traffic, HCS 2010, or Sidra].

The HCM quantifies the quality of traffic flow in terms of levels of service (LOS). There are six levels of service, with LOS A indicating very low levels of delays and LOS F indicating high levels of delays associated with congestion. These represent a qualitative measure of operational conditions within a traffic stream, and the perception of conditions by motorists and/or passengers. Levels of service and capacity for signalized intersections are calculated for each lane group (a lane group may be one or more movements), each intersection approach, and the intersection as a whole. The intersection level of service is merely a weighted average of the individual approaches and may not be considered a valid measure of the quality or acceptability of an intersection design since it can conceal poor operating conditions on individual approaches.

Levels of service at unsignalized intersections are only calculated for minor movements since the through movement on the major street is not affected by intersection traffic control. The level of service for signalized intersections and unsignalized intersections can be compared.

The level of service for freeway facilities is a measurement of density expressed as the number of passenger car equivalents/lane/mile. The corresponding level of service represents the congestion of the roadway.

LOS for Signalized Intersection

| |LOS by Volume-to-Capacity Ratio (v/c) |

|Control Delay (s/veh) |v/c ≤1.0 |v/c >1.0 |

|≤10 |A |F |

|>10-20 |B |F |

|>20-35 |C |F |

|>35-55 |D |F |

|>55-80 |E |F |

|>80 |F |F |

HCM 2010, Exhibit 18-4, p. 18-6

LOS for non-signalized Intersections

| |LOS by Volume-to-Capacity Ratio (v/c)a, b |

|Control Delay (s/veh) |v/c ≤1.0 |v/c >1.0 |

|≤10 |A |F |

|>10-15 |B |F |

|>15-25 |C |F |

|>25-35 |D |F |

|>35-50 |E |F |

|>50 |F |F |

NOTE: a, b For approaches and intersection-wide assessment, LOS is defined solely by control delay.

2-way stop control - HCM 2010, Exhibit 19-1, p. 19-2

a All way stop control - HCM 2010, Exhibit 20-2, p. 20-3

b Roundabout control - HCM 2010, Exhibit 21-1, p. 21-1

3.1 Growth Rates

State the traffic growth rates. This data is available from NYSDOT Data Services Bureau or the Regional Planning Group.

EXAMPLE: Growth rates for this project were as follows:

Interstate and ramps: 1.7% / year as per NYSDOT Data Services Bureau

All other roads: 2% per year per NYSDOT Region 3 Planning Group

3.2 Existing Traffic Counts and Volume Data as AADT/DHV

State if existing AADT information is available on the NYSDOT Traffic Data Viewer , or from the Regional Traffic Office. Attach the volume report in Appendix A.

If existing AADT information is not available, describe the methods used to collect volume data. Counts should be taken on Tuesday – Thursday during the school season, excluding holiday weeks.

• Mainline counts

• Driveway counts for existing commercial driveways

• Turning counts at intersections (as needed)

Show the methodology to convert the hard counts into AADT/DHV. Daily and seasonal adjustment factors should be used and are available on the NYSDOT Highway Data Services Webpage

EXAMPLE: Traffic Volumes were obtained from the NYSDOT Traffic Data Viewer and no hard counts were taken. Existing volumes are shown in the table below:

|Exhibit 3.2 |

|Existing Traffic Volumes for Study Area (No Build) |

|STREET NAME |EXISTING |ETC |ETC+20 |ETC+30 |

| |(2008) |(2010) |(2030) |(2040) |

| |

|Existing and Future No-Build Highway Level of Service |

|EASTBOUND |

|Road |Limits |Existing 2008 |ETC1 2010 |ETC+20 2030 |

|CR 72 |SR 14 to Ridge Road |A |A |B |

|Proposed Intersection Level of Service |

|Major Road |Minor Road |ETC1 |ETC+20 |

| | |2010 |2030 |

|SR 14 |CR 72 |B |C |

3.7 Capacity Analysis for Proposed Build Condition

Provide a capacity analysis for the proposed build condition. For major commercial driveways an analysis must be provided at each signalized intersection adjacent to the proposed driveway(s). In addition, signals within ½ mile of the proposed development should be checked for operation if there is an expected increase in left turns at that intersection. Identity the software used for the analysis. Include the output file from the software in Appendix C. For major commercial driveways the software input file shall be provided to NYSDOT in electronic format.

EXAMPLE: The proposed build level of service calculations for streets within the study area were computed using HCS+ computer software. The output file from the HCS+ analysis is attached in Appendix C.

|Exhibit 3.5 |

|Future Build Highway Level of Service |

|Road |Limits |Existing 2008 |ETC1 2010 |ETC+20 2030 |

|CR 72 |SR 14 to Ridge Road |A |A |B |

|Proposed Intersection Level of Service |

|Major Road |Minor Road |ETC1 |ETC+20 |

| | |2010 |2030 |

|SR 14 |Commercial Driveway |A |B |

|SR 14 |CR 72 |B |C |

3.8 Mitigation Measures

Identify any proposed mitigation measures that will be required for the proposed build condition:

• Addition of turn lanes

• Installation or re-timing of traffic signals

• Signage or striping to prevent unwanted turning movements from the proposed driveway

• TDM (Travel Demand Management) and TSM (Transportation Systems Management) may be incorporated as mitigation measures in congested areas. See HDM Chapter 24 for additional guidance on mobility measures.

Validate the proposed mitigation measures by providing a check against accepted data (reduction in crash rates, improvement in capacity analysis, etc.)

EXAMPLE: The proposed two-lane commercial driveway will be installed along the east side of SR 14. Due to the anticipated volumes of left turning traffic from southbound SR 14 into the driveway, the state highway will be widened and a left turn lane added. The proposed driveway will be stop controlled. Adequate horizontal, vertical, and intersection sight distance exists to accommodate traffic entering from the proposed driveway to SR 14 from a stop controlled intersection.

4.0 Crash Analysis

The purpose of this crash analysis is to identify safety problems by studying and quantifying accidents within and immediately adjacent to the driveway, and identifying abnormal patterns and clusters. An accident cluster is defined as an abnormal occurrence of similar accident types occurring at approximately the same location or involving the same geometric features. The severity of the accidents should also be considered. A history of accidents is an indication that further analysis is required to determine the cause(s) of the accident(s) and to identify what actions, if any, could be taken to mitigate the accidents.

A crash analysis was performed in accordance with NYSDOT Highway Design Manual, Chapter 5, Section 5.3.4.

The project will fall under one of the following conditions. High Accident Location (HAL) information is available from the Regional Traffic Office. Include one of the following statements:

A. [There are High Accident Locations (HAL’s) within 0.1 miles of the proposed driveway. A crash analysis is required.] (Designer must fill out Section 4 of this report)

B. [There are no High Accident Locations (HAL’s) within 0.1 miles of the proposed driveway. A crash analysis is not required.] (Designer should not provide any further crash analysis)

4.1 Existing Crash Data

Crash data will be provided by the Regional Traffic Office for existing High Accident Locations (HALs). If HALs exist, a crash analysis should be prepared for state highway segments for 0.1 miles in each direction from the proposed commercial driveway entrance(s) onto state highways. If there are major intersections near the analysis limits, these may be used as logical termini for analysis.

EXAMPLE: The 0.6 mile segment of SR 14 studied (RM 14-9101-1072 to RM 14-9101-1078) was the scene of twenty-three accidents in the three year period from January 1, 2010 to December 31, 2013. There were six accidents that resulted in injury, four accidents that resulted in property damage only, and thirteen accidents that were non-reportable. None of the accidents involved a bicycle or a pedestrian

4.2 Analysis of Crash Data

Crash analysis for HALs (Priority Investigation Locations, Priority Investigation Intersections Safety Deficient Locations) should review existing highway conditions and identify and deficiencies or contributing factors. For Major Commercial Driveways, include the summary tables and crash diagrams in Appendix D.

EXAMPLE: The area from RM 9101-1074 to 9101-1077 appears on the current (2005) HAL list as an SDL. The area from RM 9101-1070 to 9101-1080 appears on the current (2005) HAL list as a PIL for Category 51: All Fixed Object and Run off Road accidents. There have not been any HSIP studies completed in this area in the past five years.

4.3 Compare Rates to Accepted Values

Present the calculated crash rates for the segment and compare to the statewide average rate for similar segments. The data should be in table form if multiple segments are analyzed. Statewide rates are available on NYSDOT’s Office of Modal Safety and Security webpage:

EXAMPLE: The overall accident rate for the segment was 0.60 Accidents per Million Vehicle Miles (ACC/MVM). The comparable statewide average accident rate is 0.72 (ACC/MVM).

4.4 Mitigation Measures

Crash Modification Factors (CMF) and Crash Reduction Factors (CRF) are an excellent tool that can be used to estimate the expected crash reduction and/or the expected safety benefits associated with various countermeasures. These may be useful in identifying the appropriate countermeasures based on the existing resources available for a project.

A CMF is a multiplicative factor used to compute the expected number of crashes after implementing a given countermeasure at a specific location. A CRF is the percentage crash reduction that might be expected after implementing a given countermeasure.

CMF = 1 – (CRF/100)

CMFs are developed based on research studies and program evaluations and can be used to compare safety conditions with or without a particular treatment or to compare alternative countermeasures. In many cases, more than one treatment is implemented at the same time. It is important to realize CMFs multiplied together, assumes the effects of each CMF are independent, which may overestimate the combined effect of multiple treatments, especially when more than one treatment is expected to reduce the same crash type. Engineering judgment must be used to assess the relationship between the various countermeasures, especially if more than three CMFs are considered.

CMFcombined = CMF1 x CMF2 x CMF3 x … x CMFi

Multiple resources are available from which widely accepted CMFs can be obtained to provide safety practitioners with an estimate of countermeasure effectiveness. Practitioners should make every effort to use a CMF applicable to their state and local roadway conditions. Use one of the following sources to obtain the CMF:

1. PIES – Reduction Factor Report; available online on NYSDOT’s Office of Modal Safety and Security webpage:

2. FHWA Crash Modification Factors Clearinghouse; search for various CMFs on this Web-based database, includes supporting documentation:

3. AASHTO Highway Safety Manual 1st Edition, Volume 3, 2010; CMFs for various roadway types and various countermeasures:

EXAMPLE: Mitigation measures may include:

• Installation of turn lane from state highway into commercial driveway

• Layout of commercial driveway exit to permit right turns only

• Installation of crosswalk at existing nearby traffic signal to accommodate expected pedestrian traffic into the proposed commercial development

APPENDIX A

EXISTING VOLUME REPORT

FOR ALL SEGMENTS WITHIN STUDY LIMITS

APPENDIX B

EXISTING CONDITION CAPACITY ANALYSIS OUTPUT

APPENDIX C

PROPOSED CONDITION CAPACITY ANALYSIS OUTPUT

APPENDIX D

CRASH ANALYSIS DIAGRAMS/TABLES

(Required for major commercial driveways only)

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