Traffic Analysis



PIN xxxx.xx

One sentence description of proposed project

TRAFFIC IMPACT STUDY

FOR DOT PROJECTS

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 9/16/2014.

Table of Contents

1.0 SUMMARY OF TRAFFIC IMPACTS 3

2.0 TRAVEL SPEEDS 3

3.0 CAPACITY ANALYSIS 4

3.1 Growth Rates 5

3.2 Existing Volumes 6

3.3 Traffic Control Device Data 6

3.4 Capacity Analysis for Existing Condition 7

3.5 Capacity Analysis for Proposed Condition 7

3.6 Capacity Improvement Measures 8

4.0 CRASH ANALYSIS 9

4.1 Existing Crash Data 8

4.2 Analysis of Crash Data 10

4.3 Compare Rates to Accepted Values 10

4.4 Crash Reduction Measures 11

APPENDICIES 11

A Volume Report 13

B Existing Condition Capacity Analysis Output 14

C Proposed Condition Capacity Analysis Output 15

D Crash Analysis Diagrams/Tables 16

1.0 Summary of Traffic Impacts

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

A. [A capacity analysis was performed per NYSDOT Highway Design Manual Chapter 5. The following capacity improvement measures are cost effective, and are recommended to reduce reoccurring delay: __________________.]

B. [The proposed project will maintain an acceptable Level of Service of ___ or better in design year 20___.]

C. [The project includes segments that will be below the minimum Level of Service, however it is not feasible (not cost effective) to implement capacity improvements as part of this project. See Section 3.0 for more details.

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

A. [A crash analysis was prepared in accordance with Highway Design Manual Chapter 5. The following crash reduction measures have been approved by the Regional Traffic and Safety Section and are recommended to reduce the severity and frequency of crashes: __________]

B. [A minimum three-year accident history review was performed and the safety screening met all of the required steps. A full crash analysis is not required.]

C. [A full crash analysis was prepared and there were no recommended mitigation measures. Refer to Section 4.0 for additional details.]

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 Posted 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-1 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 within the project require a capacity analysis per NYSDOT Highway Design Manual Chapter 5.]

(Designer must fill out Section 3 of this TIS)

B. [Traffic conditions within the project fall in the L.O.S. “D or Better” for urban highways; or the L.O.S. “C or Better” zone for rural highways. Further capacity analysis is not required.]

(Designer should omit the remainder of Section 3 of this report, and continue with Section 4)

Lane widths are necessary for HCS (Highway Capacity Software) computations.

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, Sidra]. Choose as many as apply

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

LOS for Freeway Facilities

|Level of Service |Density (pc/mi/ln) |

|A |≤11 |

|B |>11-18 |

|C |>18-26 |

|D |>26-35 |

|E |>35-45 |

|F |>45 or any component vd/c ratio > 1.00 |

HCM 2010, Exhibit 10-7, p. 10-9

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 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 |

3.5 Capacity Analysis for Proposed Build Condition

Provide a capacity analysis for the proposed build condition. For intersection projects an analysis shall be provided at each adjacent intersection. In addition, signals within ½ mile of the project 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 consultant designed projects, 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 |

3.6 Capacity Improvement Measures

Identify any capacity improvement measures that will be required for the proposed build condition. Delay based user cost should be factored into the analysis where appropriate to assist in selecting the most cost effective improvement. Capacity improvements may include such improvements as:

Addition of turn lanes

• Installation or re-timing of traffic signals

• Signage or striping to prevent unwanted turning movements at intersections

• Conversion of a signalized or unsignalized intersection into a roundabout

• 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.

EXAMPLE: Due to the identified capacity deficiencies (delay of over 120 sec) for left turning traffic from southbound NY 14 onto NY 171, NY 14 will be widened and a left turn lane added. The signal at the intersection of NY 14 and Front St. will be retimed to allow a longer green time for Front St. This will reduce the length of the queue during the peak hour, which has been documented to occasionally back up to the intersection of CR 72 and Front St. Plans showing the above improvements are found in Appendix XX of the Design Approval Document.

4.0 Crash Analysis

A minimum three-year accident history review was performed for the period Month/Year to Month/Year. The review included all highways within the project limits and extended 0.3 mile beyond each project limit. A Safety Screening was performed based on the following:

1) The overall accident rate is less than 1.5 times the average rate for a comparable type facility as shown in SIMS;

2) There are no non-standard features within the limits reviewed that could be associated with a High Accident Location (HAL) or other identifiable pattern of crashes.

3) The occurance of Fatal, Injury and combined Fatal+Injury accidents is not above average;

4) Any locations on the regular Priority Investigation Location (PIL) list within the limits reviewed have been addressed. A PIL is considered addressed if it has been investigated within the last 5 years and the recommendations implemented or planned to be implemented by this or another programmed project.

5) Any locations on the Fixed Object & Run-Off Road PIL list or any locations on the Wet-Road PIL list are addressed.

The project will fall under one of the following conditions. Accident rate information is available from the Regional Traffic Office. Include one of the following statements:

A. [Based on the accident history review, one or more of the steps listed above in the Safety Screening are not met. A crash analysis is required.] (Designer must fill out Section 4.1 thru 4.4 of this report)

B. [Based on the accident history review, all of the steps listed above in the Safety Screening are met (Designer is not required to provide any further crash analysis, however, the documentation used to satisfy the Safety Screening steps (e.g., SIMS output) should be included in the Traffic Appendix of the DAD)

Identifying the cause(s) of accidents usually will provide an insight into what corrective measures can be taken to minimize future accidents. All Crash Analysis procedures shall follow the guidance presented in the NYSDOT Highway Design Manual, Chapter 5, Section 5.3.4.

The purpose of an accident analysis is to identify safety problems by studying and quantifying accidents within and immediately adjacent to the project limits, 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.

Project developers, in conjunction with the Regional Transportation Systems Operations Group, are responsible for retrieving and analyzing accident data in accordance with this procedure and for incorporating appropriate accident countermeasures (safety improvements) into each capital project. To achieve the Department's goal of continually improving highway safety for the public, effective accident countermeasures must be designed into its projects to the maximum extent possible.

4.1 Existing Crash Data

A crash analysis should be prepared for state highway segments for 0.3 miles in each direction from the proposed project limits. 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

A crash analysis was performed in accordance with the Highway Design Manual Chapter 5. 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. Include the summary tables and crash diagrams in Appendix D. TE-56, TE-213

If there are non-standard features within the study limits, note whether there are any HALs or other identifiable crash patterns that could be associated with the non-standard feature(s).

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.

The area from RM 7802-1003 to 7802-1009 contained 5 accidents involving vehicles leaving the road. This segment contains a curve with a radius of 350 ft (compared to the standard of 550 ft) and the existing superelevation is 4.5% (compared to the current standard of 8%).

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:

The accident rate for this segment of Route ___ is ___ accidents per million vehicle miles. This is above/below the statewide accident rate for similar facilities, which is ____ accidents per million vehicle miles.

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 Crash Reduction 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:

Safety practitioners tabulate the chosen CMFs on NYSDOT form TE-164 – Safety Benefits Evaluation Form. This form calculates the total accident reduction based on all of the chosen countermeasures. An estimated annual safety benefit cost will be calculated from the proposed improvements. This form is included as a section of the accident analysis.

The process for completing Form TE-164:

1. Fill in project information: Location, Study Period, alternative number, and proposed improvements.

2. Identify the mitigation measures that will be required for the proposed build condition.

• Safety improvements

• Installation or re-timing of traffic signals

• Changes to signage or striping, etc.

3. Use the applicable sources to determine the CMFs for the chosen countermeasures.

4. Calculate the accident reduction for the chosen mitigation countermeasures; include formulas for any combined CMFs.

5. Fill in existing accident data for the study period and the average statewide cost per accident severity type. This will determine the total cost for this segment before and after the proposed mitigation countermeasure(s) are implemented. The estimated annual safety benefit is calculated by subtracting the estimated cost using the mitigation countermeasures from the estimated cost if no improvements were installed.

6. Fill out one form per alternative to compare the safety benefit of various countermeasure combinations.

EXAMPLE: Crash reduction measures may include:

• Installation of turn lanes on state highway to reduce rear end accidents.

• Removal or shielding of fixed objects within the clear zone.

• Installation of crosswalk at existing nearby traffic signal to accommodate expected pedestrian traffic within the project limits.

• Prohibiting on-street parking or converting free parking into regulated on street parking.

• Converting a signalized intersection into a modern roundabout.

• Providing traffic calming and/or speed transitions to reduce speeds in developed areas with a high percentage of speed-related crashes.

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

TE-156a

TE-164a

TE-204a

TE-213

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