Residential parking requirements specify the number of parking spaces that must be provided when new residential units are built. How these parking requirements influence housing affordability is examined. The provision of parking spaces requires land, building materials, and equipment, which increase the price of housing. On the other hand, it is a common belief that off-street parking requirements prevent streets from being overcrowded with parked cars. In a case study of six neighborhoods in the city of San Francisco, the influence on housing affordability of code-required parking was studied. A hedonic model was fit to data that described housing and neighborhood characteristics to explain statistically the sales price of housing units that changed hands in those neighborhoods in 1996. The analysis revealed that single-family houses and condominiums were more than 10 percent more costly if they included off-street parking than if they did not. Based on the selling prices and the distribution of incomes of San Francisco residents, it was estimated that tens of thousands of additional households could qualify for home mortgages for units without off-street parking if those units could be provided legally under zoning and subdivision ordinances. The policy implications of this finding include the possible consideration of alternative forms of regulation pertaining to the provision of off-street parking in residential projects.

A review of the shale wellbore stability mechanism based on mechanical-chemical coupling theories, Petroleum (2015), Abstract: Wellbore instability in hard brittle shale is a critical topic related to the effective exploitation of shale gas resources. This review first introduces the physical-chemical coupling theories applied in shale wellbore stability research, including total water absorption method, equivalent pore pressure method, elasticity incremental method of total water potential, and non-equilibrium thermodynamic method. Second, the influences of water activity, membrane efficiency, clay content, and drilling fluid on shale wellbore instability are summarized. Results demonstrate that shale and drilling fluid interactions can be the critical factors affecting shale wellbore stability. The effects of thermodynamics and electrochemistry may also be considered in the future, especially the microscopic reaction of shale and drilling fluid interactions. An example of this reaction is the chemical reaction between shale components and drilling fluid.

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