I.

Purpose. The purpose of a traffic impact analysis (TIA) is to identify the relationship between land use and transportation system. The TIA is intended to ensure adequate review and consideration of potential impacts of proposed development on the surrounding thoroughfare and local street system. The city requires that TIAs be performed for both zoning requests and site plan processes.

II.

Traffic impact analysis.

A.

Acceptable level of service. A level of service "C" is the design objective for the city. A TIA must attempt to identify sufficient transportation improvements to achieve or maintain a level of service "C" or better.

B.

Study area. The minimum transportation impact study area shall include the entire neighborhood plus any neighborhood that abuts or is adjacent to the proposed development.

C.

Contents. Specific report requirements may vary depending on the site location and characteristics, geographic area, and size and type of development. However, each TIA must clearly state all assumptions and methodologies, and contain at a minimum, the following:

1.

Transportation system.

a.

Vicinity map that relates the site location to the thoroughfare and local street system.

b.

Thoroughfare designation according to the city thoroughfare plan.

c.

Number of roadway lanes, lane widths, and right-of-way widths.

d.

Traffic signal locations.

2.

Land uses.

a.

Existing and proposed (if applicable) land use characteristics for the subject site.

b.

Number of acres (gross and net) classified by zoning and density.

c.

Approximate gross square footage of existing and proposed structures.

D.

Background traffic.

1.

Existing conditions.

a.

Current traffic counts (both average daily traffic and morning and afternoon peak hours) on thoroughfares and collectors around the site shall be collected for the TIA and the counts shall be not more than one year old. The city's most current annual traffic counts may be used for the TIA if available.

b.

Turning movements at critical intersections should be collected for the intersection's analysis.

c.

For proposed new developments, if the site will be built in the future year, projected growing traffic volume, calculated by using a growth factor, between the current year and a tentative built year should be added to the current traffic counts. The growth factor will be determined by the city based on historical data from the city's annual counts.

2.

Projected build-out assumptions.

a.

Projected traffic volume for build-out scenarios will be provided by the city by using the results from TranPlan model completed by North Central Texas Council of Government for Collin County 2020 Long Range Transportation Plan update.

b.

Projected traffic volume for the streets, which were not included in TranPlan model analyses, should be calculated by using a growth factor. The growth factor will be provided by the city based on historical data from the city's annual counts.

E.

Site traffic; trip generation.

1.

Assume full development and occupancy.

2.

Show in tabular form the land use components, the trip generation rates (daily and peak hour), and total trips generated by land use types.

3.

Use the latest Trip Generation Manual published by Institute of Transportation Engineers.

4.

No passerby trip reductions allowed.

F.

Capacity analysis.

1.

Separate maps illustrating traffic volumes for different scenarios:

a.

Nonsite traffic projections for design year (ADT and AM/PM peak hour turning movements);

b.

Development traffic (ADT and AM/PM peak hour turning movements); and

c.

Nonsite traffic plus development traffic for design year (ADT and AM/PM peak hour turning movements).

2.

Capacity analysis of roadway links shall be performed for the ultimate design. Identify level of service with and without development site traffic. If the roadway links exhibit a LOS D, E, or F, then intersection analyses will need to be performed for those facilities.

G.

Mitigation of impacts.

1.

Identification of actions or alternatives required to maintain an acceptable level of service on the street system. Candidate actions include:

a.

Roadway link and intersection improvements.

b.

New or modified traffic signals.

c.

Access locations and driveway design.

d.

Transportation system management programs.

e.

Neighborhood traffic deviators/controls.

2.

Site plans or preliminary engineering plans for all thoroughfares, local streets, and intersection improvements must as a minimum conform to the requirements of the city's land development code.

H.

Revised traffic figures. If the proposal is significantly revised by the commission and/or city council, then revised traffic figures must be generated in order to comply with the final recommendation.

I.

Waiver of requirement. If the proposed development or zoning change generates less than 1,000 average daily trips, the city's traffic engineer may waive the requirement.

J.

Completion by registered professional engineer. The traffic impact analysis shall be completed by a registered professional engineer with a background in traffic engineering.

(Ord. No. 1939-5-01, 5-3-2001)