COOPERATIVE AGREEMENT - Laserfiche WebLink

Task 8: Model Validation Purpose The purpose of this task is to adjust the model so that the travel demand modeling system produces realistic, validated estimates of current traffic -flow patterns in'the Tri-Valley area. Approach and Methodology The CONSULTANT shall exccum the trip generation, trip distribution, modal split, and trip assignment modules for the I990 base year and measure the accuracy of the model against actual traffic volumes. The CONSULTANT shall validate the model to the following jurisdictions_ tolerances, by jurisdiction, for ADT, and peak -hour directional traffic or levels mutually agreed upon by the Authority, the Counties and Seventy-five percent of freeway link volumes wiH be within +/- 20 percent_ Fifty percent of freeway link volumes will be within +/- 10 percent. Seventy-five percent of major arterial link volumes will be within +/- 30 hence!r Fifty percent of major arterial link volumes wall be within +/- 15. percent Intersection movements greater than 1,000 vehicles per hour — 50 percent will be within +/- 20 percent_ Intersection movements between 500 and 1,000 vehicles per hour — 30 percent wiL ; within +/- 20 percent These tolerances are based on direct output from Emmet and do not include any manual adjustments. Higher tolerances will be achieved by manually adjusting the model output and developing, where appropriate, factors to bring the model generated numbers closer to the counts. Intersection turning movements will be estimated based on using the Ferness adjustment method as described in the Authority's Technical Procedure Manual_ The intersection analysis will be conducted using adjusted volumes_ The CONSULTANT shall prepare detailed comparisons of observed and estimated average daily (and AM and PM peak -hour) traffic volumes at critical roadway sections and screcnlines, as well as peak -hour turning -movement volumes at intersections in the Tri-Valley area to test the models' accuracy_ Based on the moults, adjustments shall be made in the modcli.ng process, and new model runs shall be performed Cooperative Agreement No. 45.01.00 -Exhibit A Between Contra Costa Transportation Authority and Page 9 of 13 County of Alameda, Pleasanton, Dublin, and Livermore