27 CAR § 95-408. Assessment of existing conditions

(a)(1) Other than to support the purpose and need by analyzing the no-build alternative, assessing the existing conditions is essential to calibrate the chosen analysis tool or tools. (2) Any chosen analysis tool must be calibrated. (3) This applies to tools such as Synchro/SimTraffic, HCS, CORSIM, and VISSIM. (b) Some of the key issues to calibration include: (1) Identification of necessary calibration targets of acceptability, i.e., calibrating the through-put turning movement volumes at existing intersections to within ten percent (10%); (2) Allocation of sufficient time and resources to achieve calibration targets; and (3) Selection of the appropriate calibration parameters to best match local observations, i.e., saturation flow-rate, travel time, average speed, through-put volume, etc. (c) Because existing conditions within each proposal study area will be unique and because the level of calibration effort, which can be complex and time-consuming, can depend on the chosen tool, discussion with Arkansas Department of Transportation Planning and Research Division staff should occur during early coordination.