Transit-Oriented Development
How urban form determines climate impact
Your Progress
Section 4 of 5Urban Form = Climate Destiny
The most impactful climate decision a city makes isn't technology—it's where and how densely to build.
❌ Sprawl Model
- → Single-family homes on large lots
- → Separated uses (residential, commercial, industrial)
- → Car-dependent: avg 35+ miles/day driven
- → Per-capita emissions: 3-5 tons CO2/year (transport)
✅ TOD Model
- → Mixed-use buildings within 1/2 mile of transit
- → 15-minute neighborhoods (walk to daily needs)
- → Multi-modal: transit, bike, walk, micro-mobility
- → Per-capita emissions: 1-1.5 tons CO2/year (transport)
The numbers are stark: A person living in sprawl emits 2-3x more from transport than someone in a transit-oriented neighborhood. Globally, urban form determines 40% of transport emissions—more than vehicle efficiency.
🎯 Interactive: Transit vs. Sprawl Comparison
Compare two development patterns for the same population. Watch how density affects emissions, costs, and livability.
City Population
500KCar-Dependent Model
Transit-Oriented Model
🏙️ Six TOD Design Principles
1. Density Gradients
Highest density within 1/4 mile of station (12-20 floors), tapering to 3-6 floors at 1/2 mile. Ensures ridership while respecting neighborhoods.
2. Mixed-Use Mandate
Ground floor retail, residential above, offices nearby. Creates 18-hour activity, supports local businesses, reduces commute trips by 30-40%.
3. Parking Minimums → Maximums
Traditional codes require 1-2 spaces per unit. TOD caps at 0.5-1. Frees land for housing, cuts construction costs $25-50K per unit.
4. Pedestrian-First Streets
Wide sidewalks (12-15ft), protected bike lanes, street trees, slow traffic (15-20 mph). Safety increases walking by 50-80%.
5. Frequent Service
Transit every 5-10 minutes peak, 15 minutes off-peak. Eliminates schedules—just show up. Ridership doubles vs. 30-min headways.
6. Affordable Housing Integration
20-30% below-market units required. Prevents displacement, ensures diverse neighborhoods, concentrates transit benefits equitably.
🌍 Cities That Got It Right
🇩🇰 Copenhagen: The 15-Minute City
62% of residents bike to work/school (vs. 1% US average). Integrated metro, S-train, bus rapid transit. Zero-car neighborhoods like Nørrebro. Result: 45% of trips by bike, 20% transit, 35% car.
🇨🇳 Shenzhen: Electric Transit
100% of 16,000+ buses are electric (since 2017). 12 metro lines, 300+ km of track. Mixed-use TOD mandated for all new developments. Population 13M, density 7,000/sq mi.
🇨🇦 Vancouver: SkyTrain Network Effect
68 km automated metro (since 1985) shaped city growth. 80% of new housing within 800m of stations. Car ownership: 550 per 1,000 people (vs. 800 North America avg). Upzoning near stations funded transit expansion.