Overview

Employing the World Health Organization Health Economic Assessment Tool (HEAT), we can determine that cyclist training in Central Park prevents ~26 premature deaths annually, or $343 million per year in economic benefit. We can model also the impact of 15 mph speed cap: every 1% change in participation ≈ 1% change in mortality benefit.

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#1 – Assess the public health value of cyclists training in Central Park using the WHO/HEAT tool

Use Assumption:

• Cyclists comprise 45% of 42 million visitors per year to Central Park
• 42 million x 45% = 18.9 million
• 18.9 million ÷ 365 days = 51,781 cyclists training for one hour per week
• 51,781 ÷ 2 = 25,890 cyclists training twice per week for an hour

ChatGPT Query: Using the WHO/HEAT tool, quantify the reductions in mortality of from 25,890 people biking one hour, twice a week in Central Park and convert this economic value (HEAT Monetization)

ChatGPT Reply: Here is a clean application of the World Health Organization Health Economic Assessment Tool (HEAT) methodology for 25,890 people cycling 1 hour twice per week.

1️⃣ Cycling Exposure

Assumption:

• 25,890 adults
• 1 hour × 2 per week = 120 minutes/week

HEAT dose–response:

• 100 min/week → 10% reduction in all-cause mortality
• Linear scaling up to 45% cap

At 120 minutes/week: 120/100×10% = 12% relative risk reduction

2️⃣ Baseline Mortality

Using a typical U.S. annual mortality rate:

• 8.5 deaths per 1,000 people = 0.0085 annual mortality rate

Expected annual deaths without cycling: 25,890×0.0085 = 220 deaths/year

3️⃣ Deaths Prevented

• 220 deaths × 0.12 ≈ 26 premature deaths avoided annually

4️⃣ HEAT Monetization (Value of Statistical Life)

HEAT monetizes avoided deaths using national Value of a Statistical Life (VSL).

• Current U.S. DOT guidance:  $13 million per statistical life
• Economic value: 26.4 × $13,000,000 ≈ $343,200,000

📊 Final HEAT Output

If 25,890 people cycle 2 hours per week year-round:

• ~26 premature deaths prevented annually
• ≈ $343 million per year in economic benefit

Sensitivity Range

• Mortality reduction = 10–13%
• VSL = $10–15 million

Annual economic value range: $260M – $400M per year

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#2 – Model the impact of a speed limit reduction to 15 mph 

ChatGPT Query: Based on these numbers, estimate impact of a 15 mph cap on mortality exposure.

ChatGPT Reply: Using the HEAT baseline we just calculated:

Baseline (25,890 riders)

• ~26 premature deaths avoided annually
• ≈ $343 million annual economic value

Under the World Health Organization HEAT framework, speed itself does not directly reduce benefit unless it lowers total physical activity. A 15 mph cap only changes mortality impact if it reduces participation or minutes ridden. 

Step 1 — Marginal Value Per Rider

• 26 deaths avoided / 25,890 riders ≈ 0.0010 deaths avoided per rider per year
• Economic value per rider: $343M / 25,890 ≈ $13,250 per rider per year
• This makes modeling simple: Every 1% change in participation ≈ 1% change in mortality benefit.

Step 2 — Modeled Participation Declines

Scenario A — 5% decline (≈1,295 fewer riders)

• Deaths avoided: 26 × 0.95 = 24.7
• Additional deaths: ≈ 1.3 per year
• Economic loss: ≈ $17 million annually

Scenario B — 10% decline (≈2,589 fewer riders)

• Deaths avoided: 26 × 0.90 = 23.4
• Additional deaths: ≈ 2.6 per year
• Economic loss: ≈ $34 million annually

Scenario C — 15% decline (≈3,884 fewer riders)

• Deaths avoided: 26 × 0.85 = 22.1
• Additional deaths: ≈ 3.9 per year
• Economic loss: ≈ $51 million annually

Scenario D — 20% decline (≈5,178 fewer riders)

• Deaths avoided: 26 × 0.80 = 20.8
• Additional deaths: ≈ 5.2 per year
• Economic loss: ≈ $69 million annually

Key Insights

Under HEAT:

• If total cycling time remains constant → near-zero mortality impact
• If participation drops → mortality benefit declines linearly
• Each 1% reduction ≈ 0.26 additional deaths per year
• Each 10% reduction ≈ ~$34M in lost annual economic value