Month Year Traffic Impact Study - NYSDOT Project Project Title
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. STAMPNote: 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)
https://www.dot.ny.gov/divisions/engineering/applications/traffic-data-viewer
Exhibit 1Speed Data /
Street Name / Limits
(From – To) / Posted Speed / Actual Operating Speed /
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, bControl 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 https://www.dot.ny.gov/divisions/engineering/applications/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 https://www.dot.ny.gov/divisions/engineering/technical-services/highway-data-services
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 3.2Existing Traffic Volumes for Study Area (No Build)
STREET NAME / EXISTING
(2008) / ETC
(2010) / ETC+20
(2030) / ETC+30
(2040)
AADT / DHV / AADT / DHV / AADT / DHV / AADT / DHV
SR 14 / 5000 / 180 / 5200 / 180 / 7200 / 250 / 8200 / 290
CR 72 / 3000 / 110 / 3120 / 110 / 4320 / 150 / 4920 / 170
3.3 Traffic Control Device Data
Identify existing traffic control devices. If traffic signals are involved, a table should show information (provided by the Regional Traffic Office) identifying which approaches have detection and provide signal timing data.
EXAMPLE: There are no traffic lights within the study area. There is a flashing blinker at the stop controlled SR 14/CR 72 intersection. All other intersections and commercial driveways within the study area are stop controlled.
3.4 Capacity Analysis for Existing No-Build Condition
Provide a capacity analysis for the existing no-build condition. Validate the model by providing a check against accepted data. Identity the software used for the analysis. Include the output file from the software in Appendix B. For consultant designed projects, the software input file shall be provided to NYSDOT in electronic format.
EXAMPLE: The no-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 B.
Exhibit 3.5 /Existing and Future No-Build Highway Level of Service /
EASTBOUND /
Road / Limits / Existing 2008 / ETC1 2010 / ETC+20 2030 /
SR 14 / CR 72 to Main Street / B / B / B /
CR 72 / SR 14 to Ridge Road / A / A / B /
Proposed Intersection Level of Service /
Major Road / Minor Road / ETC1
2010 / ETC+20
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 /
SR 14 / CR 72 to Main Street / B / B / B /
CR 72 / SR 14 to Ridge Road / A / A / B /
Proposed Intersection Level of Service /
Major Road / Minor Road / ETC1
2010 / ETC+20
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)