What is the I-Value in Signals and how is it computed?
The Upstream Filtering and Metering Adjustment Factor (I) accounts for the filtering effects of upstream signals within a mile of the analysis signal on each approach. It is based on the weighted average of the v/c ratios of the upstream contributing movements (automated in Signals) and can make a significant difference in the d2 delay, especially where the subject approach has v/c ratios approaching or exceeding 1.0.
