Parking cost is a key aspect of the generalized cost used in mode choice modeling. It is also an important policy variable that gains more and more attention in Transportation Demand Management (TDM) strategies. Traditionally, parking costs are collected manually through labor-intensive and costly surveys. Then typically a parking cost model is built with some statistical analysis to relate the costs to explanatory variables such as employment density, population density, and parking demand at the zonal level. Due to the limited availability of parking cost data, it is very challenging to develop and update models as frequently as needed.
With the emergence of web-based databases, private vendors are collecting parking related information and providing free access to the data via interactive webpages or mobile apps. The data includes up-to-date parking rates (hourly, daily, monthly), parking capacity, and geographic location. These services are available in many major metropolitan areas in the U.S. and the coverage is growing rapidly. What is especially attractive is that some vendors even provide access to their Application Programming Interface (API), that can be used to receive updated data in real-time. This provides a great opportunity for planning agencies to get up-to-date data at no or much lower cost.
This study uses a market-based approach to equilibrate parking demand with parking supply in Southern California. On the supply side, the up-to-date parking database is obtained through private vendors with detailed information on parking rates, capacity, and location for 2,962 facilities in the region. The data quality is validated against other public data sources. On the demand side, the 2012 California Household Travel Survey provides valuable information on the parking fees paid and subsidy received by trip purpose. Other explanatory variables include socio-economic and land use characteristics for each Traffic Analysis Zone.
This study's contributions are: 1) a cost-effective method to collect updated and detailed information on parking cost, and 2) a market-based approach to estimate future parking costs.