Travel Time Reliability Reference Manual/Primary use in SHRP II

TICAS is the software that is primarily used for travel time and vehicle miles traveled (VMT) data collection in Strategic Highway Research Program 2 (SHRP II) Project L38-Pilot Testing of Reliability Data and Analytical Tools. TICAS calculates and provides cumulative travel time with records every 0.1-mile from the specified start point to the end point along the corridor. Data is available in varying time intervals, ranging from 30 seconds to one hour.

For primary test, three corridors were selected, and the routes were created and save in TICAS. The start and end points for the corridors are listed below in Table 1.

Table 1: Corridor Boundaries

The team downloaded data from January 2006 through December 2012 for each corridor. Downloading the traffic data was a time consuming effort due to the fact that the TICAS software is only capable of calculating two months of data per query. In addition, when downloading the data for TH 100, TICAS would tend to quit working if more than two weeks of data were selected at one time, due to the large number of stations along the corridor. If days with no travel time or VMT data available were selected when using TICAS, an “Error in evaluation” message would appear. When this occurred, each individual day had to be checked to determine which days were missing data. After recognizing that, in general, the only days with missing data were the first Saturday and Sunday of November each year (on occasion, the last weekend of October was missing data), the search was narrowed down fairly quickly and the days with missing data were simply not selected in TICAS.

Table 2: Days with Missing TICAS Data

For the further extension of the SHRP II Project L38, the team also downloaded the travel time and VMT data from TICAS on I-35E and TH 13. Instead of performing analysis with seven-year data, only data in year 2012 was downloaded.

In summary, TICAS is a powerful software that could provide corridor-based traffic metrics like travel time and VMT. The data can be collected in every 30 seconds and can be specified in every 0.1 mile. However, there are some limitations when using TICAS. Firstly, downloading the traffic data with multiple years was a time consuming effort due to the fact that the TICAS software is only capable of calculating two months of data per query. Secondly, there is no button like "Select All" which enable user to download the data in large number of days. For example, if user needs to download certain traffic data for a whole year in 2012, TICAS does not allow selecting 366 days in 2012 directly, but select one by one for 366 times. Thirdly, TICAS cannot identify the specific date with error traffic data, but only give user a “Error in evaluation” message. When this occurs, each individual day has to be checked to determine which days are missing data.

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