These guidelines detail the procedures to be utilized when conducting a traffic impact study for a proposed subdivision or site development which is expected to impact traffic operations on the adjacent road network. Such studies are necessary to define the possible magnitude of the impact(s) of the proposed subdivision or development on the traffic operations of affected roadways and intersections and determine improvements necessary to provide for accommodation of the traffic due to the proposed subdivision or development.
A.
Traffic impact studies are conducted to enable the Township to identify the potential impacts of a proposed subdivision or development and determine any roadway improvements necessary to provide an acceptable level of service. These studies are to be conducted during the initial stages of the review and approval process in order to adequately consider the impacts the additional traffic will have on the local transportation network.
B.
Not all subdivision or development projects will have a significant enough impact to require a traffic impact study. The use of engineering judgment is necessary in making this determination and consideration should be given not only to changes in projected traffic volume but also safety or capacity deficiencies which could impact the roadway system. At a minimum, a traffic impact study should be performed when either of the following conditions is satisfied:
(1)
The proposed subdivision or development is expected to generate 1,500 or more vehicle trips per day (total inbound and outbound development traffic).
(2)
The proposed subdivision or development is expected to generate 50 or more vehicle trips that are newly generated peak direction trips to or from the site.
C.
In all cases, a traffic impact study will be conducted when, in the opinion of the Township, the subdivision or site development is expected to have a significant impact on the safety and/or traffic flow of the affected roadway(s).
A.
When it has been determined that a traffic impact study is required for a proposed subdivision or site development, it shall be the responsibility of the applicant to ensure the study is conducted and a final report submitted in accordance with these guidelines. The traffic impact study and final report shall be prepared under the supervision of a qualified and experienced Transportation Engineer with specific training in traffic and transportation engineering.
B.
The conduct of the traffic impact study must be in cooperation with and coordinated with the appropriate local officials. Of special importance is the need to work closely with the involved officials in determining the improvements which are to be implemented on the affected roadway(s).
C.
When requested by the applicant, the Township will perform a "procedural review" of the draft traffic impact study report. This review will be limited to insuring the proper procedures have been used and adequate documentation has been provided in accordance with the requirements of these guidelines. This "procedural review" is intended to provide the study preparer with guidance on the adequacy of the study in meeting the requirements of these guidelines and will not address the adequacy or appropriateness of the recommended improvements.
A.
General requirements.
(1)
The traffic impact study (TIS) will be conducted using currently accepted traffic engineering practices and procedures. The use of computer programs to conduct the required analyses is acceptable; provided, the programs reflect the most current provisions of the analysis procedure upon which they are based. Recommended geometric or traffic operations improvements must meet or exceed all applicable state and/or local minimum design criteria.
(2)
The TIS engineer will be responsible for the collection of all information and data required to support the TIS effort. At the developer's request, the Township will make available appropriate information and data which will assist in the TIS effort. When additional traffic counts are required for the TIS, the engineer shall collect such data to include peak hour turning movements on an average week day, as well as on Saturday, if required, as defined in PennDOT's Publication 201. Traffic data may not be older than three years.
(3)
The procedures and requirements outlined in these guidelines are intended to provide a basic framework for the conduct of a TIS. Additions or modifications to this framework may be made provided such changes are approved by the Township.
B.
Study area characteristics.
(1)
The limits for the study area should be based upon engineering judgment and a knowledge of the existing traffic conditions in the vicinity of the proposed subdivision or site development. The area must be of sufficient size to include the key roadway corridors and critical intersections which may be impacted by the proposed site traffic. Designation of the study area boundaries shall be a cooperative effort between the engineer, Township and/or PennDOT. In those instances where agreement cannot be reached on the boundaries, the Township will establish the boundaries to be used for the TIS. Designation of the future design year(s) as the basis for the study will be made by the Township dependent on the timing and/or phasing of the proposed project.
(2)
Existing and proposed land uses in the study area must be considered in the TIS. This consideration must include not only the current/proposed zoning of the various tracts within the study area, but also the specific use for the development site. Where the current/proposed land use of the site is being modified, an analysis of the proposed changes should be made to determine the extent to which traffic volumes for the site will be modified.
(3)
Characteristics of the study area roadway network, intersections and the proposed site access point(s), to include geometries and traffic control need to be identified as part of the TIS. Included in this identification will be all driveways adjacent to or across from the proposed site access point(s). In addition, all committed roadway and traffic operational improvements to the study area network, which will occur during the designated time period on which the TIS is based, are to be identified.
C.
Traffic analysis.
(1)
The study area roadway network is to be analyzed for safety and capacity sufficiency for three separate conditions: existing network conditions, future network conditions without the proposed development, and future network conditions with the proposed development. For each of the three conditions the following analyses shall be completed:
(a)
Mainline average daily traffic (ADT) volumes and turning movement volumes for all critical intersections within the study area will be determined for the a.m. peak hour, p.m. peak hour and the proposed development peak hour, which may be Saturday, if other than either the a.m. or p.m. peak hour of the network.
(b)
The effectiveness of the traffic signal control at all critical intersections will be evaluated by approach in terms of vehicle stops and delays.
(c)
Gap studies will be conducted at the proposed site access points to evaluate the need for signal control, turn prohibitions or additional site access points to reduce the left turn volume from the site driveway(s).
(d)
Queue length analyses will be completed to evaluate the potential for a backup of traffic from controlled intersections which could impact other intersections, including access points to the proposed development.
(2)
An analysis of the volume and capacity of the network and all critical intersections will be conducted utilizing the most current highway capacity manual procedures. Levels of service will be determined and documented. The analysis of the existing roadway and intersection conditions in the study area will be based upon the current geometric conditions and traffic control operations. This analysis will serve as a basis for determining the current adequacy of the roadway network and to document any deficiencies. The analysis of the future conditions without the proposed subdivision or development will document the adequacy of the study area network to accommodate traffic in the design year(s) without the proposed development. This analysis must include a full consideration of all committed roadway improvements to the study area network when determining the expected levels of service. For the analysis of the future conditions with the proposed subdivision or development, one of the key factors will be the development of the projected site generated traffic and its distribution on the study area network. The study preparer must fully document the methodology which is used to complete this effort and provide sufficient information such that the Township can verify the results. In addition, care must be taken to ensure that adequate consideration is given to that portion of the already projected future network traffic which will utilize the proposed development access points. (Failure to account for this "captured" traffic will result in a "double counting" of a portion of the future traffic).
D.
Improvement recommendations.
(1)
The overall goal of this section will be to detail necessary improvements to the study area roadway network which will provide for a level of service for the design year(s) with the development which is at least equivalent to the projected level of service for the design year(s) without the proposed subdivision or development. Based upon a comparison of the traffic analysis for the future conditions with and without the proposed subdivision or development, roadway and traffic operational improvements which will support this goal are to be identified and analyzed. These improvements may include both on-site and off-site roadway and traffic operational changes as determined by the preceding analyses. In developing the proposed improvements, the study preparer is to consider the following:
(a)
All highway capacity evaluations shall consider not only the overall intersection level of service and delay but also evaluate each approach and movement to identify any substandard values which need to be improved.
(b)
For locations where the level of service of the design year without the proposed development is Level of Service C, the improvements shall provide an estimated delay which will be no worse than the delay for the design year without the proposed subdivision or development.
(c)
Where new intersections are being established to serve as access to the proposed development, these intersections must be designed to at least operate at Level of Service C or better.
(d)
For access points to the proposed development, which are not proposed to be controlled by a traffic signal, an analysis will be completed to determine the design details for a separate left turn lane on the adjoining highway.
(e)
For access points to the proposed development where traffic signal control is being proposed, a traffic signal warrant analysis shall be performed in accordance with the requirements of PennDOT's Publication 201. Although a left turn lane shall be provided, an analysis shall be completed to determine the type of signal phasing required.
(2)
The final recommended study area network with proposed improvements will also be subjected to all the traffic analyses which are required under the previous section of these guidelines. These analyses will serve to document the "adequacy" of the improvements.
A.
General.
(1)
A final report must be prepared to document the results of the traffic impact study and the recommended improvements to accommodate the projected traffic due to the proposed subdivision or development. Since this report will be reviewed by Township officials with varying levels of technical expertise, the report must be presented in a format and context which can be understood by both technical and nontechnical parties.
(2)
The presentation of data and analyses results should, preferably, be accomplished on either schematic diagrams of the study area, or through the use of charts and/or tables. All sources of data and methodologies which were used in the TIS (including computer programs) must be properly referenced and documented. Any modifications to the referenced procedures must be properly documented to enable a review of the appropriateness of the modification.
B.
Contents. The final report will include the following:
(1)
Executive summary which provides a concise description of the study area, results of the traffic analyses, and any recommended improvements.
(2)
Description of the proposed subdivision or development site to include a map showing the site's location in regards to the region and the area roadway network.
(3)
Schematic diagram/map of the designated study area showing all major highways and critical intersections.
(4)
Results of the traffic analyses for the three traffic conditions. At a minimum, the following data must be shown for each of the three conditions:
(5)
Recommended improvements to the study area network to include preliminary cost estimates, proposed implementation schedule and expected levels of service for the recommended network.
C.
Review procedures. Five copies of the final TIS report shall be submitted for review and approval. Reports which do not contain the required information or indicate that the study was not done in accordance with the requirements of these guidelines will be returned to the applicant for correction and resubmission.
If a developer believes that the preparation of traffic study and report required herein is not warranted, he may request the Board of Supervisors to waive the preparation of such study and report and shall make an estimated contribution of the sum necessary to defray the costs of improvements which would be recommended by such studies. The estimated contribution shall be in accordance with the current adopted Township Fee Schedule.
A.
The developer of any commercial, industrial or institutional subdivision or land development shall provide the Township with a certification of the usable building floor area to be constructed for the purpose of determining the contribution in lieu of preparation of studies.
B.
This contribution in lieu of preparation of studies provided for herein shall be in addition to all charges imposed by the Authority for tapping and connection fees and shall be in addition to all other review. Inspection and other fees or charges imposed by the Township and/or the Authority, and all sums otherwise agreed to be paid by the developer.
C.
The developer shall enter into an agreement with the Township setting forth the contribution in lieu of preparation of studies to be paid and the studies to be waived by the Township. All such agreements shall be in a form satisfactory to the Township Solicitor.
D.
All contributions in lieu of preparation of fees shall be paid prior to approval of the final plan by the Township.
A.
Highway Capacity Manual, Special Report 209, Transportation Research Board, 1994.
B.
Trip Generation, latest edition, Institute of Transportation Engineers.
C.
Site Impact Traffic Evaluation Handbook, Federal Highway Administration, 1985.
D.
Development and Application of Trip Generation Rates, Federal Highway Administration, 1985.
E.
NCHRP Report 187, "Quick Response Urban Travel Estimation Techniques and Transferable Parameters: User's Guide," Transportation Research Board, 1978.