The Connected Corridors team had already gathered considerable data about the I-210 corridor as part of the corridor selection process, in order to assess its suitability for the pilot. Once I-210 had been chosen, the project team expanded its data-gathering in an effort to understand the corridor as thoroughly as possible.
The types of data collected include:
- Geometry of intersection approaches (number of lanes, lane markings, length of turning bays, turn restrictions) for approximately 525 intersections. This information was generally retrieved from maps or aerial photos from Google Maps. This required considerable time and effort, particularly to measure the length of turning bays using a Google Maps application.
- Location of traffic sensors on the freeway mainline, freeway ramps, and individual intersection approaches. While sensor layout diagrams were provided for most of the corridor intersections, these diagrams did not always indicate the exact location of sensors on each approach. The location of sensors had to be visually verified and extracted from Google aerial and street view photos for approximately 300 intersections. In these cases, a Google Maps measuring tool was used to determine the location of each sensor relative to the downstream stop line.
- Available signal timing sheets from Caltrans, LA County, and local jurisdictions.
- Available intersection detection layout diagrams from Caltrans, LA County, and local jurisdictions.
- Available five-minute traffic counts from the Arcadia TransSuite system and available vehicle detections from the Arcadia Bluetooth sensor network, both from December 2013 to present. A connection was established with the Arcadia TransSuite traffic signal control system, enabling the project team to get real-time access to signal status data from all city-operated signals, five-minute traffic counts from about two thirds of the city-operated intersections, and one-minute travel time data from the city-operated Bluetooth sensor network.
- One-week sample of signal timing and 15-minute traffic flow data from the Pasadena i2 centralized traffic signal control system.
- Reports on traffic impact studies that have been conducted for proposed projects within the I-210 corridor over the past eight years.
- Synchro model developed by Iteris covering a significant portion of the city of Pasadena.
In analyzing the data, the project team:
- Developed several maps of corridor systems. While many maps already existed, these maps generally covered only a specific system. What was needed in the corridor were maps that included all the existing systems in a single document. Efforts were thus required to transpose data from one mapping system to another.
- Conducted various analyses on the Arcadia real-time data to assess their quality, identify typical daily flow profiles, and determine how the available data could be used to determine flow patterns at individual intersections and through the city. This required reviewing detailed timing data from 51 intersections and sensor data from 367 detection stations covering a six-month period.
- Conducted a preliminary analysis of the quality of the traffic flow data sample that was obtained from the city of Pasadena. This required reviewing and analyzing data from over 500 sensors across 70 intersections covering a seven-day period.
- Assessed how vehicle counts from existing traffic detection locations may be used to determine traffic flow patterns along specific arterials and within the corridor. This is a complex analysis that required several weeks to process data from various arterial segments and, for each arterial segment considered, data from various periods.
The project team modeled arterials within the I-210 corridor in Synchro, a commonly used signal optimization software. This model currently models nearly 500 signalized intersections. While half of this modeling re-used a Synchro model that was developed by Iteris for the city of Pasadena, information from the source model had to be reviewed to correct several inaccuracies and code several missing intersections. Coding of the remaining intersections, particularly the signal timing information for each intersection, required substantial effort. This modeling will eventually be used to assess the operational effectiveness of existing traffic signal control plans under existing flow patterns, as well as existing and proposed control plans under assumed traffic conditions. It is also used to assess data gaps and needs.
List of data collected
The following table lists the types of data collected. To see the files for each type, click the blue headings below or the links in the sidebar:
Freeway RampsRamp Metering - LMR Tables
Road Network Information
Travel Impact Studies