Results from the Planning for Operations Case Study from the Metropolitan Transportation Commission in San Francisco California
Applying Analysis Tools in Planning for Operations: Case Study #3 – Using Archived Data As a Tool for Operations Planning
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.