What percentage of street miles have sidewalks in major US cities?

NYC: 99%. Boston: 96%. SF: 95%. Philadelphia: 93%. Chicago: 88%. DC: 86%. LA: 71%. Seattle: 68%. Atlanta: 41% (mid-case). Houston: 28%. Phoenix: 19%. NYC-to-Phoenix is 80-point range.

How many street miles lack sidewalks in the largest cities?

Houston: 4,488 miles. LA: 2,310 miles. Atlanta: 1,106 miles. Charlotte: 1,984 miles. Phoenix: 4,212 miles. These absolute numbers represent thousands of blocks where pedestrians must walk in the road.

When does a city's street network determine sidewalk presence?

Pre-1945 networks (NYC, Boston, SF, Philadelphia): ~99% coverage. Post-1965 networks (Phoenix, Jacksonville, Nashville, Houston): 19-28% coverage. Median street age is the primary predictor. FHA and ITE subdivision standards (1950s-1970s) made sidewalks optional on residential streets.

What is the relationship between missing sidewalks and pedestrian deaths?

NHTSA crash data shows Houston pedestrians killed disproportionately on US-59, US-90, I-45, and Sam Houston Tollway frontage roads where sidewalks do not exist. The crash record cites "in the roadway," technically accurate because no sidewalk existed.

How much does it cost to close a city's sidewalk gap?

Basic 5-foot concrete sidewalk: $25-40 per linear foot. Houston's 4,488-mile gap (one side only, low end): $1.18B. Charlotte's 1,984-mile plan: $50M/year over 30 years ($1.5B total). At current funding, most gaps take 100+ years to close.

Where the sidewalk ends. Mapping the gaps in major US metros.

Atlanta has sidewalks on 41% of its street miles. Houston has 28%. Phoenix, 19%. The gap is the single best predictor of where pedestrians have to walk in the road.

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