1. Alternative Road Impact Fee Methodologies
Clancy Mullen, AICP
Duncan Associates
Austin, TX

2. Basic Impact Fee Formula
Travel Demand (Trips or Vehicle-Miles)
[Consumption-Based Must Use VMT]
X Cost per Trip/VMT
[Consumption: Cost ÷ Capacity]
[Improvement: Cost ÷ Future Trips or VMT]
= Gross Impact Fee

3. Consumption-Based Method
Cost of Representative List of Projects
÷ Vehicle-Miles of Capacity (VMC)
= Cost per VMC
x System VMC/VMT Ratio
= Cost per VMT

4. Improvement-Based Method
Cost of Improvements Needed
÷ Projected New Trips or VMT
= Cost per Trip or VMT

5. History of ACHD’s Impact Fees
1989: Original Study by Duncan Assoc.
1991: Auto Tag Fee Increase Vote
1992: Ord. 184
1992: Idaho Development Fees Act
1993: CIP and Revised Ordinance
1995: CIP Update
1996: Revised Study by Duncan Assoc.
1999: Ord. 193 Based on Staff Study
2000: Developers Sue
2001: Ord. 194 Based on Updated Study
2002: HB 604 Amended State Act
2003: Ord. 197 Based on Improvement Method

6. Original Study Consumption-Based Methodology
Fees Varied Based on Trip Length
County-Wide Construction/ROW Costs
Trip Length Reduced for State Roads
Four Assessment Districts
Boise/Garden City ($837)
Western Cities ($900)
Near Rural ($964)
Far Rural ($1,039)

7. 1999 Amendments (Ord. 193) County-Wide Fee for Residential Uses
Variable Fee for Nonresidential:
Boise/Garden City ($3,158/1000 sf)
Eagle ($2,701)
Meridian ($2,466)
Kuna/Star ($1,486)
Variable ROW Costs ($22k-$365k/LM)
Credit Error: Pk Hr Cost – ADT Credit
Reduced Construction Cost

8. Assessment Districts

9. Benefit Districts

10. Idaho HB 607, effective 3/2002 Micron vs. Ada County Hwy Dist
Micron expanding plant, wanted credit for all past and future taxes to ACHD
Law now requires credit based on what developer paid
Unfair to New Firms to Area

11. Advantages of Standards-Driven Method
Flexibility to Spend Revenues
No Need to Be Tied to Specific List of Projects
Simple to Calculate

12. Advantages of Improvements-Driven Method
Ties Fees to Improvements Benefiting Development
Sound “Rational Nexus” to Impacts
Ensures No Fees Used to Pay for Deficiencies
Relates Directly to CIP and Long Range Plans