B.4. - ASSESS PROJECT IMPACTS

B.4.1.   Project Impact Assessment

The key elements of the project impact assessment include evaluations of issues outlined for a specific Analysis Level.

A.

Project Impacts. The key elements of the project impact analysis include:

• Generalized Daily Traffic Volume Level of Service

• Using the daily traffic volumes forecast and general daily level of service thresholds, a general evaluation should be made of the arterial roadway system for the short term and long-term horizon years. Incremental differences attributable to the land use action should be identified. A map showing generalized levels of service should be presented for each design year.

• For unsignalized intersections of 2 lane (and rarely on 4-lane) roads, where traffic on the main road is not stop controlled, an evaluation for the need for auxiliary speed change lanes is to be provided (reference Section 2.3.7.D).

• Peak Hour Intersection Level of Service

• An a.m. and p.m. peak hour intersection level of service analysis shall be conducted for each intersection, based on procedures specified in the Highway Capacity Manual. All level of service analysis worksheets shall be included in the Appendix.

• The principal objective of the intersection level of service traffic impact analysis is to identify whether the traffic from the proposed project when added to the existing plus short and long term planning horizon traffic will result in a significant impact and an unacceptable LOS. For definitional purposes, the threshold for acceptable LOS is not less than LOS D for peak hours.

• Significance for signalized intersections is defined as when the added project traffic causes an intersection to fail the minimum acceptable LOS standard; or when the background traffic conditions (without project traffic) causes an intersection to fail the minimum acceptable LOS standards; and when the project traffic causes more than a 2 percent increase in the intersection delay. Significance for unsignalized intersections is defined when backstacking to adjacent intersections would create impeded traffic flows and/or excessive congestion; when added project traffic is determined to create potential safety problems.

B.

Traffic Signals and Access Locations. Traffic signals warranted by the land use action a signal warrant analysis (based on the MUTCD) shall be identified. The acceptability of the signal locations must be demonstrated through a signal progression (time-space) analysis. The analysis shall consider any existing access or intersection or a possible future signal location along the arterial for a distance of at least one mile in each direction of the proposed signal. A cycle length of between 80 and 120 seconds should be selected and agreed to by the ECM Administrator. A travel speed of 45 mph on majors and 35 mph on minors, unless the existing posted speed limit is less, must be used. A major arterial bandwidth of 50 percent and a minor arterial bandwidth of 40 percent are considered desirable, and must be used where existing conditions allow. Where intersections or other accesses have no signals presently, but are expected to have signals, a 60 percent mainline, 40 percent cross roadway, and cycle split should be assumed. Where more detailed information is available from turning movement projections, other split assumptions may be made.

Any access where a signal would reduce the desirable bandwidth shall be identified. In general terms, that access should remain unsignalized and have turning movements limited by access design or median islands, unless the impacts to traffic operation and safety are made worse. The implications of the land use action upon the adequacy of the signal locations for each design year shall be provided. Distances between signalized intersections (centerline) shall be indicated. Signal progression worksheets (time-space diagrams) shall be included in the TIS Appendix.

The following signalization and access parameters shall also be addressed:

• Turn lane storage needs shall be identified for the "necessary" situation, based on projected turning volumes and AASHTO analytic techniques. Appropriate documentation of the calculations must be provided;

• The identification of project sight distance at the project entrances and all internal roadways shall be conducted. Line of sight triangles for determining sight distances and landscape restrictions shall be prepared and submitted.

• Appropriateness of acceleration or deceleration lanes.

• All proposed project entrances on arterials shall be evaluated as to whether they require acceleration lanes or deceleration lanes per the requirements presented in these Standards.

C.

Pedestrian and Bicycle Impact Evaluations. Pedestrian and bicycle facility demand shall be identified and related items for discussion shall include:

• School routing plans shall be developed per the MUTCD between the project and all schools within 2 miles of the project boundary.

• The demand for pedestrian and bicycle facilities to serve high pedestrian activity areas with the land use shall be evaluated and properly accommodated for the planning of the project.

• The need for links of bicycle or pedestrian facilities to neighboring land uses or attractions (trails, etc.) within 1,320 feet or greater if applicable to unique pedestrian-oriented destinations) of the project site.

• Existing and proposed sidewalk width, separation from traffic, and space available for trees, public transportation services stops (if any), or other related elements (if any).

• Geometric improvements and recommended traffic control devices to accommodate pedestrians and bicyclists.

D.

Pedestrian and Bicycle Level of Service. Existing and proposed pedestrian and bicycle facilities shall be evaluated for compliance with the following elements:

1.

Directness. Walking distance to destinations like public transportation services stops, schools, parks, and commercial or activity areas shall be direct. Measurement of directness is the ratio of the actual distance to a destination via a sidewalk or pathway divided by the minimum distance characterized by a grid roadway system,

2.

Continuity. The sidewalk/walkway system shall be complete, without gaps. The pedestrian corridor shall be integrated with the activities along the corridor and shall provide continuous access to destinations,

3.

Roadway Crossings. Safety and comfort is essential while crossing roadways, intersections, and mid-block crossings. Factors that affect safety include number of lanes to cross, crossing delay for pedestrians, signal indication, cross-walks, lighting, raised medians, visibility, curb ramps, pedestrian buttons, convenience, comfort, and security,

4.

Visual Interest and Amenity. Pedestrians enjoy visually appealing environments that are compatible with local architecture and include roadway lighting, fountains, and benches.

5.

Security. Pedestrians shall be visible to motorists, separated from motor vehicles and bicycles, and under adequate roadway lighting.

6.

Surface Condition. Pedestrian facilities shall be free from obstructions, cracks, and interruptions.

E.

Special Studies. This section provides the ECM Administrator with opportunities to require specific focused traffic analyses that may be unique to the proposed land use action. The ECM Administrator will determine if special studies are required in a Scoping Meeting. These may include, but are not limited to, the following:

1.

Access Management.  

• If a development is proposing a new access location on an arterial and an Access Management Plan does not exist, the ECM Administrator may require an Access Management Plan. Proposals to access roads classified as arterials and above shall require review through the Major Thoroughfares Task Force Process;

• Access spacing;

• Accident/safety concerns (accident statistics);

• Truck routing;

• Emergency and snow routes; and

• Hazardous materials routes.

2.

Neighborhood Transportation Impact Evaluation. The TIS may be required to include a focused analysis of the potential project-related impacts on adjacent residential neighborhood quality of life issues, such as potential cut-through traffic and speeding/volume concerns. If it is determined that a neighborhood transportation impact evaluation is required, the following procedure shall be followed:

• Examine existing transportation conditions within the neighborhood following the procedure as set forth for the transportation impact analysis. Daily and peak hour traffic volumes shall be collected for the local roadways to be included in the analysis;

• Determine project-generated traffic for all modes within the neighborhood and show on a figure;

3.

Determine total traffic projections for the local roadways. This shall follow the same procedures as described earlier, including other projects and area-wide growth, if applicable:

• Determine if the proposed project would create significant impacts to the residential roadways;

• If necessary, develop measures including, but not limited to, traffic calming techniques, to mitigate any significant impacts; and

• The neighborhood TIS shall also discuss how pedestrians and bicyclists would access the proposed project from the adjacent neighborhood(s), and the need for special facilities to enhance direct pedestrian and bicycle connectivity.

4.

Sight Distance. Sight distance concerns that are anticipated or observed which may impact access, intersection, or roadway operation and safety need to be discussed in the TIS. Recommendations regarding stopping sight distance, intersection sight distance, and passing sight distance needs shall be provided for detailing on the final development, site plan, or final construction plans.