The objective of this project was to develop system designs for programs to monitor travel time reliability and to prepare a guidebook that practitioners and others can use to design, build, operate, and maintain such systems. Generally, such travel time reliability monitoring systems will be built on top of existing traffic monitoring systems. The focus of this project was on travel time reliability. The data from the monitoring systems developed in this project – from both public and private sources –included, wherever cost-effective, information on the seven sources of non-recurring congestion. This data was used to construct performance measures or to perform various types of analyses useful for operations management as well as performance measurement, planning, and programming. The datasets in this zip file, which is 338.39 MB in size, are in support of SHRP 2 reliability project L38A, "Pilot testing of SHRP 2 reliability data and analytical products: Southern California." This report can be accessed via the following URL: https://rosap.ntl.bts.gov/view/dot/3611 This zip file contains 11 files, including 8 Microsoft Excel worksheets (XLSX), 2 Comma Separated Values (CSV), and 1 Zip Package (PKZIP) files. The Microsoft Excel worksheets can be opened using the 2010 and 2016 versions of Microsoft Word, the CSV files can be opened using most text editors, and the PKZIP files can be opened using most zip file extraction programs.