​An overabundance of free or low-rate parking can have several effects. First, it may promote commuters to drive single-occupant vehicles rather than ridesharing or taking transit. This may lead to increased congestion on the highway network. It hinders short-term parking needed for commercial areas.

Parking Pricing is a strategy to limit the parking demand which in turn may reduce single occupancy travel. Rates charged for parking vary by demand.  Typically, rates increase as the demand increases. Often parking pricing, in combination with reduced parking requirements for development, shared parking and other techniques may be implemented as a TDM strategy (to reduce vehicle traffic in an area) and ways to maximize developable land.

​References

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 Victoria Transport Policy Institute
Parking Pricing means that motorists pay directly for using parking facilities. Parking Pricing may be implemented as a TDM strategy (to reduce vehicle traffic), as a Parking Management strategy (to reduce parking problems), to recover parking facility costs, to generate revenue for other purposes (such as Transportation Management Association or downtown improvement district), or a for a combination of these objectives.
Victoria Transport Policy Institute

TCRP Report 95 Parking Pricing and Fees
The nation's growth and the need to meet mobility, environmental, and energy objectives place demands on public transit systems. Current systems, some of which are old and in need of upgrading, must expand service area, increase service frequency, and improve efficiency to serve these demands.
TCRP Report 95 Parking Pricing and Fees.pdf

Parking Spaces/Community Places (EPA)
Many communities are evaluating parking issues as part of a broader process of reevaluating their overall goals for growth. They want and need new residents and jobs - for vitality, economic growth, and other reasons - but they need to decide how and where to accommodate them. In cities, towns, and countryside, new and newly rediscovered development patterns offer solutions.
Parking Spaces/Community Places (EPA)

Reforming Parking Policies to Support Smart Growth
This report is intended to serve as a guide or a handbook for communities interested in planning and implementing parking policies and programs that are supportive of Smart Growth and Transit Oriented Development (TOD). The focus is on downtowns, neighborhoods, and transit station areas in which a major investment has been made to provide regional and local transit accessibility.
Reforming Parking Policies to Support Smart Growth