Parking facilities are a critical part of a transportation system: vehicles are typically parked about 23 hours per day and require parking at every destination. These facilities impose various economic, social and environmental costs. This report describes how to estimate the number of parking spaces that exist in an area, their total costs, and optimal pricing. This information is important for many policy and planning decisions. Recent surveys indicate that typical North American communities have three to eight parking spaces per vehicle, including many seldom-used spaces. Considering land, construction and operating expenses, their total annualized costs per space typically range from about $600 for a basic surface lot on inexpensive land to more than $5,000 for high-amenity structured parking. Overall, their costs are estimated to average about $1,000 annually per space or $5,000 per vehicle-year, totaling more than a trillion dollars per year in the U.S. For every dollar a motorist spends on their vehicle somebody typically spends about a dollar on parking for its use. Most parking costs are external, resulting in higher taxes, rents and retail prices, plus significant environmental damages. These external costs are economically inefficient and unfair since they increase total parking and traffic costs, and force households that drive less than average to cross-subsidize higher-mileage motorists. More efficient parking management can provide larger savings and benefits than previously recognized.