On any approach to a traffic signal where a traffic control monitoring system is in use, the agency shall ensure that the yellow change interval on that approach is not shorter in duration than that determined by the formula set forth in §B of this regulation, following any adjustments required by §C of this regulation. Formula. The formula for calculating the yellow change interval (in seconds) is: Adjustments to Calculated Yellow Change Interval. The calculated yellow change interval shall be rounded up to the nearest half second. If the calculated yellow change interval is less than 3.0 seconds, then the yellow change interval shall be 3.0 seconds. If the calculated yellow change interval is greater than 6.0 seconds, then the yellow change interval shall be 6.0 seconds.