Resolve conflicts between traditional data sources by using archived data.

Results from the Planning for Operations Case Study from the Metropolitan Transportation Commission in San Francisco California

Date Posted

Applying Analysis Tools in Planning for Operations: Case Study #3 – Using Archived Data As a Tool for Operations Planning

Summary Information

As part of an effort to prioritize highway improvements to reduce bottlenecks and congestion, the Metropolitan Transportation Commission (MTC) of the San Francisco Bay Area in California, utilized archives to provide the data for the "existing conditions" portion of the analysis that enables the MTC to prioritize projects. The MTC relies on several different data capture methods in order to provide a broad view of their ongoing traffic conditions. Many of these data sets have several years of archived data.

Lessons Learned

In corridors where there were multiple data sets available for analysis, in the case of conflicting data, staff took a look at historical Performance Monitoring System (PeMS) data in order to determine which data source was most likely correct for that given day or time. This process required qualified staff who were able to effectively mine the data and determine the accuracy of the data received from the sensors. If the data were not analyzed, assessed for reasonableness, and compared against other sources, or if the data had been misinterpreted, the conclusions from the analysis could be unreliable.

Unreliable or nonexistent detector data had to be imputed based on nearby detectors and historical data. However, this method is only effective if the defective sensors are distributed across the system and not in clusters. Otherwise, the imputation would cause inaccurate results.