(a)   Traffic impact studies (TIS) can be a valuable planning tool for the City.  A traffic impact study allows the City to better understand the impact a proposed development will have on adjacent roads, intersections, and site access driveways before the Planning Commission or City Council approves the development. This type of planning provides the ability to make modifications to the proposed plans and/or plan for the mitigation of the traffic impact prior to the development being constructed.
   (b)   Important questions that may be answered by a traffic impact study:
      (1)   Are the number of access points the minimal necessary to serve the project without negatively impacting the flow of traffic along arterial streets?
      (2)   Are the proposed access points a sufficient distance from intersections to minimize conflicts?
      (3)   Are proposed access points adequately spaced from other access points along the street?
      (4)   Should left turns be restricted by signs, channeled driveways, or the installation of a median?
      (5)   Have other methods of access, such as shared driveways, frontage roads or access off a side street been evaluated?
      (6)   Is the sight distance adequate at proposed access points?
      (7)   Are deceleration lanes necessary?
      (8)   Is the throat length at the driveway sufficient to minimize conflicts within the site?
      (9)   Can trucks and waste-hauling vehicles easily access the site and circulate to and from loading areas?
      (10)   Is the design sensitive to pedestrian needs?
   (c)   The traffic impact study guidelines presented in this section will perform the following functions:
      (1)   Establish standards of study;
      (2)   Ensure that important traffic concerns are addressed;
      (3)   Provide staff with a check list for the review process;
      (4)   Promote an increased understanding of traffic impact issues for those involved in the development process.
   (d)   A full or partial traffic impact study will be required for any proposed development when the Planning Commission has determined, after receiving input from the subdivision review staff, that street capacity and/or safety are concerns, or when a proposed development will generate 100 or more added new peak hour trips to or from the site during the adjacent roadway's peak hours or the development's peak hour.
   (e)   The use of the 100-vehicle threshold is reasonable because in an hour an additional 100 vehicles can:
      (1)   Change the level of service at an intersection;
      (2)   Require the addition of turn lanes to accommodate site traffic while not impacting through traffic;
      (3)   Lead to a need for additional traffic control measures such as stop signs, blinking lights, and/or traffic signalization;
      (4)   For residential developments, 100 peak hour traffic trips are likely to be generated by:
         A.   150 single-family detached homes;
         B.   245 apartments;
         C.   295 town home condominiums.
      (5)   For commercial development, 100 peak hour traffic trips are likely to be generated by:
         A.   A 15,000 square foot shopping center;
         B.   A 37,000 square foot medical/dental office;
         C.   A 55,000 square foot general office building;
         D.   A 115,000 square foot light industrial use;
         E.   A 250,000 square foot manufacturing use;
         F.   An 85,000 square foot research and development facility;
         G.   A 4,400 square foot bank with drive-throughs;
         H.   A convenience store with 5 gasoline pumps; and
         I.   A 5,200 square foot restaurant with a drive-through window.
   (f)   In some cases, a proposed development may generate fewer trips than the threshold indicated above, but a safety or capacity issue in the area of the proposed development may require a full or partial impact study for the following reasons:
      (1)   High accident intersection or section of roadway;
      (2)   Proximity of proposed site drives to other site drives or intersections;
      (3)   Sensitivity of adjacent neighborhoods;
      (4)   Existing or projected level of service of street(s) adjacent to the proposed development which is unacceptable;
      (5)   High traffic volumes on adjacent roadway(s) that may impact movement into and out of the site.
(Ord. 12-2002.  Passed 7-2-02.)