Interactive Crash Map
Click any marker to see detailed crash information and cost breakdown. Colors indicate crash severity (red = fatal, orange = serious, yellow = minor).
Cost Analysis & Distribution
Network Delay Cost by Crash Type
Crash Distribution by Category
Crash Trends Over Time
Death & Serious Injury (DSI) Trends
Fatal and serious injury crashes — the focus of road safety interventions
Minor & Non-Injury Crash Trends
Minor injury and non-injury crashes — larger volume, important for network delay costs
Detailed Cost Breakdown
| Crash Category | Count | Unit Cost Range | Total Network Delay | Social Cost | Combined Total |
|---|---|---|---|---|---|
| Loading cost data... | |||||
Methodology & Data Sources
- Crash Data Source: New Zealand Transport Agency Crash Analysis System (CAS), Auckland region, . Includes all reported crashes: fatal, serious injury, minor injury, and non-injury crashes meeting Police reporting thresholds. Total: crashes analyzed.
- Social Costs (NZTA MBCM): Primary crash costs calculated using NZTA's official Monetised Benefits and Costs Manual (MBCM v2.7.3). This is the standard methodology used for all transport project evaluation in New Zealand. Includes: medical costs, rehabilitation, property damage, statistical value of life, loss of productivity, legal costs, emergency response, and crash investigation. Values include under-reporting adjustment factors and are updated to 2024 NZD. Applied to all crashes.
- Network Delay Costs (Flow Methodology): Additional economic costs from crash-induced traffic congestion, quantified using methodology developed by Flow Transportation Specialists (commissioned by Auckland Transport, July 2025). Based on empirical analysis of 4 case study crashes with travel time data collected via TomTom GPS. Applied to crashes on major roads (motorways, arterials) where network disruption is significant.
- Flow Case Studies: Four serious/fatal crashes analyzed: motorway multi-vehicle, divided arterial, 4-lane arterial, and 2-lane arterial. Travel time impacts measured during disruption and recovery periods. No minor crash case studies were conducted by Flow.
- Network Delay Valuation: Uses MBCM composite value of time ($37-40/hour) plus congestion increments ($27-28/hour), multiplied by 3.2× unexpected delay factor from NZTA Research Report 670. Min/max ranges reflect methodological uncertainty in how the 3.2× factor is applied.
- Crash Classification: Network-impacted crashes matched to six categories based on road type, lanes, severity, and vehicle count: Motorway Multi-Vehicle, Divided Arterial Serious, 4-Lane Arterial Serious, 2-Lane Arterial Fatal, Other Serious, and Minor Crash on Major Road*.
- *Minor Crash Caveat: Flow studied ZERO minor crashes. Minor crash network costs ($5K-$10K) are extrapolated from Flow's hypothesis that minor crashes on major roads "can lead to as much network delay as a serious crash." This is unvalidated.
- Data Period: represents post-COVID return to normal traffic patterns. Some behavioral changes (remote work) may affect delay magnitudes versus pre-pandemic baselines.
- Conservative Estimates: Network delay costs exclude: vehicle operating costs, rubbernecking delays, cancelled trips, schedule reliability impacts, wider economic impacts, emergency vehicle delays. True network costs likely 20-40% higher than estimates shown.
- References: NZTA MBCM v2.7.3. Harrison, P. (2025). Network Disruption Cost of Serious Crashes. Flow Transportation Specialists. NZTA Research Report 670 (Harrison & Walton, 2020). NZTA CAS database.