How the Calculator Works

Routing

We use OpenRouteService (ORS) to compute separate walking and driving routes between your two locations. The walking route uses the foot-walking profile, while the driving route uses the driving-car profile with toll and highway distance extras enabled. These give us the distance in miles and estimated duration for each mode.

Because walking and driving routes can differ significantly — pedestrians can cut through parks, take footpaths, and cross plazas — we request each route independently rather than assuming the same path.

Time Value of Money

Your income bracket is used to estimate an hourly time value: the bracket midpoint divided by 2,080 annual work hours. For example, the $50,000–$74,999 bracket uses a midpoint of $62,500, yielding $30.05/hour.

The leisure discount. We do not value walking time at your full hourly wage. Most people choosing between walking and driving are not choosing between walking and working. Walking time can be enjoyed, used for phone calls, podcasts, or simply thinking. We apply a 50% leisure discount, valuing walking time at half of the computed hourly rate. This reflects the economic concept that leisure time has lower opportunity cost than work time, a principle well-supported in transportation economics literature.

Driving time is valued at the full hourly rate because driving demands your full attention and cannot easily be used productively.

Fuel Cost

We estimate fuel cost as driving distance / effective MPG × gas price per gallon.

Gas prices are refreshed daily from the U.S. Energy Information Administration (EIA) Petroleum Data API. For states with direct EIA coverage, we use the state-level price. For others, we use the appropriate PADD (Petroleum Administration for Defense District) regional average. A static fallback table ensures the calculator works even if the EIA API is temporarily unavailable.

MPG estimation starts from a 25 MPG national fleet average and adjusts ±1 MPG for state driving conditions (urban-heavy states like CA and NY trend lower; highway-heavy states like TX and WY trend higher). For short trips, we apply aggressive MPG penalties because cold engines, frequent stops, and city traffic dramatically reduce fuel efficiency. A 2-mile city trip may use only 56% of baseline MPG — this matches EPA cold-start testing data.

Maintenance

We apply a flat rate of $0.09 per mile for direct maintenance costs (oil changes, brake pads, filters, and repairs). This is a conservative national average derived from AAA's annual "Your Driving Costs" study, which typically reports higher per-mile maintenance costs when including labor and parts at dealership rates.

Ownership Variable Costs

Beyond maintenance, every mile driven contributes to depreciation, tire wear, and can affect insurance rates. We estimate this at a base of $0.14 per mile, adjusted by state: high-cost states (CA, NY, NJ, MA, DC, FL, MI, LA, NV, WA) add $0.03/mile, while low-cost states (IA, ID, IN, KS, NC, OH, UT, WI, NE) subtract $0.02/mile. These adjustments reflect regional differences in insurance premiums, labor costs, and vehicle depreciation rates.

Tolls and Congestion

When ORS reports toll-road distance on the driving route, we apply a per-mile toll rate that varies by state (from $0.07 in low-toll states to $0.26 in NJ and NY), plus a $1.10 base plaza fee. If your destination falls within Lower Manhattan's congestion pricing zone, we add a $5.00 congestion charge.

Parking

Driving somewhere means parking when you get there. We estimate parking costs based on trip distance and state density. Short trips in high-density states (NY, CA, DC, etc.) assume $4–$5 in parking fees and 4–5 minutes of search time. Longer trips to suburban destinations assume free parking with minimal search time. The time spent finding parking is valued at your full hourly rate, since it is not leisure time.

Environmental Cost

We include a $0.05 per mile environmental externality cost for driving. This is based on the EPA's social cost of carbon (approximately $51 per ton of CO₂) combined with average vehicle emissions of 404 grams of CO₂ per mile, plus estimated local air quality impacts. While drivers do not pay this cost directly, it represents a real societal expense — one that walking avoids entirely.

Walking Health Savings

Regular walking delivers measurable health benefits that translate into lower medical costs over time. The CDC estimates that physical inactivity costs the U.S. healthcare system approximately $117 billion per year. On a per-person basis, inactive adults spend roughly $1,500 more per year on medical care than active adults.

We estimate health savings at $3.80 per hour of walking. This is conservative: dividing $1,500 in annual savings by 182.5 hours of walking (30 minutes per day) yields $8.22/hour. Our lower figure accounts for the fact that a single walk does not guarantee the full annual benefit, and that some walkers may already be physically active through other means.

Short-Trip Driving Penalties

Short city trips are particularly expensive to drive. Cold engines burn more fuel, stop-and-go traffic reduces efficiency, and low average speeds increase idle time. We model this with distance-based MPG penalties (a 2-mile trip may run at only 56% of baseline MPG) and speed-based penalties (average speeds below 16 mph trigger an additional 12% efficiency loss). High-density states receive a bonus penalty on trips under 10 miles, reflecting heavier traffic and more frequent stops.

We also estimate idle time — the minutes spent warming up, waiting at lights, and circling for parking — which ranges from 0.8 to 4.5 minutes depending on trip distance, speed, and state density. This idle time is valued at your full hourly rate.

What We Don't Include

Our model deliberately omits several factors to keep the comparison focused and defensible:

• Weather and terrain: We do not adjust for hills, rain, or temperature, which can affect both walking comfort and driving efficiency.
• Safety: Pedestrian safety varies enormously by location and is difficult to monetize responsibly.
• Vehicle type: We use fleet averages rather than asking about your specific car, to keep the input simple.
• Carpooling or transit: This is a two-mode comparison — walking versus solo driving.
• Mental health benefits: While walking is strongly associated with reduced anxiety and depression, we do not attempt to price this.

Our Bias, Disclosed

We built this tool because we believe walking is undervalued. Our assumptions lean toward making walking's benefits visible — the leisure discount, health savings, and environmental costs are all choices that favor walking. We believe these choices are defensible and well-sourced, but we want you to know they exist. If you disagree with any assumption, the About page explains our reasoning in more detail.