JOSH — Fire Evacuation Capacity Analysis System

Berkeley, CA  •  AB 747 / Government Code §65302.15  •  v3.4 ΔT Standard

What is JOSH?

JOSH is an objective, algorithmic system that calculates whether a proposed development project materially degrades fire evacuation route capacity. It applies the Highway Capacity Manual (HCM 2022) ΔT method: each project’s peak-hour vehicle demand is compared against the bottleneck effective capacity on all evacuation paths within 0.5 miles. If the marginal evacuation delay (ΔT) exceeds the zone-specific threshold derived from NIST safe-egress windows, the project requires discretionary review. All determinations are fully reproducible from published sources — no professional judgment, no discretion.

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Demo Projects — Three-Tier Coverage Matrix

Project Scale Determination Key Factor Documents
Ashby Small Infill 10 units · 2 stories MINISTERIAL 10-unit project at Ashby BART — below the 15-unit size threshold. Standard 1 (size gate) is not triggered, so the project qualifies for ministerial approval reg… Brief Audit trail
Downtown Mid-Rise 85 units · 3 stories DISCRETIONARY 85-unit, 3-story project on Shattuck Ave. Exceeds the 15-unit threshold. Non-FHSZ → no road degradation. Mobilization rate 0.90 (NFPA 101 design basis) → 191.25… Brief Audit trail
Hills Gateway 80 units · 3 stories DISCRETIONARY 80-unit project near the Berkeley Hills in FHSZ Zone 3. Mobilization rate 0.90 (NFPA 101 design basis, constant) → 180 project vehicles. Road capacity degraded … Brief Audit trail
Hills FHSZ Small Infill 10 units · 2 stories MINISTERIAL 10-unit project in the Berkeley Hills FHSZ Zone 3 area — same location as Hills Gateway (Project 3, 80 units → DISCRETIONARY). Despite the fire zone and high mo… Brief Audit trail
Claremont Hills Terrace 25 units · 3 stories CONDITIONAL 25-unit hillside project NOT in a mapped FHSZ zone. Mobilization rate 0.90 (NFPA 101 design basis, constant) → 56.25 project vehicles. No road capacity degradat… Brief Audit trail
Cedar Street Infill 75 units · 6 stories DISCRETIONARY 75-unit, 6-story project in North Berkeley (NOT in FHSZ). Mobilization rate 0.90 (NFPA 101 constant) → 168.75 project vehicles. Building egress penalty: 6 stori… Brief Audit trail