In and around traffic, your chance of dying as a pedestrian is higher than for biking or driving: 15 per 100 million miles walked, based on an rough estimate of 32 billion miles walked, or 44 per hundred million hours.
The minimum width of a sidewalk is 4 feet, to accommodate wheelchairs. The minimum width of a walking lane on a crowded sidewalk is 2 feet, and the space taken up by a pedestrian on a sidewalk is 12 SF, or 1% of the space needed by a car.
The capacity of a 2 foot walking lane on a sidewalk is 11,000 pph. The energy consumption of pedestrianism is directly related to the calories burned: 500/BTU/mile.
The cost of building a mile of 5-foot wide sidewalk (2 pedestrian lanes) is 120,000 $/mile, or $60,000 per mile of lane. The cost of maintenance for this sidewalk is $6,000/mile/year. Public sidewalks are commonly paid for as part of highway projects, and therefore 30% percent paid for by the highway trust fund. The share of funds that goes to pedestrian projects is tiny compared to traffic-ways, usually around 1% of road project funding.