(1) The operation allocation shall be calculated using the following factors:

(a) The combined student count of basic program students;

(b) The combined student count of special program students;

(c) The district's prorated average distance;

(d) The district's total land area;

(e) The district's prorated number of destinations;

(f) If the district is a nonhigh district, the answer to the following question: Does the district provide transportation service for the high school students residing in the district?

(g) Any other district data element as described by the superintendent in the annual operations bulletin. In order for a data element to be included, it must be found to be statistically significant for two consecutive school years.

For each district, an expected allocation is determined using the coefficients resulting from a regression analysis of (a) through (g) of this subsection, evaluated statewide against the total of all school district's prior year expenditures. If a data element is determined not to be statistically significant, it shall not be included in the calculation of the allocation. The coefficients will be determined using the prior school year fall, winter, and spring reports and prior year expenditures.

(2) For the calculation of the regression analysis coefficients, the prior year expenditures for each district shall be adjusted as required by the legislature.

(3) The adjusted allocation is the result of modifying the expected allocation by:

(a) Adding any district car mileage reimbursement; and

(b) Adding any adjustment resulting from the alternate funding systems identified in WAC 392-141-380; and

(c) Making any deduction resulting from an alternate school year calendar approved by the state board of education under the provisions of RCW 28A.305.141; and

(d) Making any adjustment as required by the legislature.

(4) Each district's actual allocation for student transportation operations is the lesser of the district's prior year expenditures adjusted as required by the legislature or the adjusted allocation.

(5) The funding assumption for the transportation operation allocation is that kindergarten through twelfth grade (K-12, or whatever grades are enrolled in district schools) school transportation services are provided by the district five days per week, to and from school, before and after the regular school day and operating one hundred eighty days per school year. K-12 service being provided on any other basis is subject to corresponding proration of the operation allocation.