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Effectiveness of Disseminating Traveler Information on Travel Time Reliability: Implement Plan and Survey Results Report

CHAPTER 2. SITE SELECTION

The following sections describe the sites selected for the study. Overall, the three sites were chosen based on a variety of criteria – the corridors had challenges with congestion, reliability data for the facilities were available, and the project team had personal knowledge about the locations and close working relationships with local stakeholders that would facilitate deployment of the project.

HOUSTON, TEXAS

The Houston District of the Texas Department of Transportation (TxDOT) plans, designs, builds, operates, and maintains the state transportation system in Brazoria, Fort Bend, Galveston, Harris, Montgomery, and Waller counties. The population of the Houston District is more than 5.7 million people, with the largest city in the district being Houston, the 4th largest city in the United States. The following are key aspects of the region, which played an integral part in the study:

  • Houston TranStar®, the Houston traffic management center, is a national leader in freeway incident management and uses state-of-the-art technologies to reduce congestion on major roadways.
  • Houston TranStar® uses Anonymous Wireless Address Matching (AWAM) for traffic monitoring, which uses anonymous addresses from Bluetooth™ network devices to identify probes and calculate travel times and speeds on instrumented roadway segments.
  • The Houston region has the ability to provide travel updates to drivers during daily commutes as well as in emergency evacuation situations.
  • Houston TranStar® collects and archives historical speed data that could be utilized for this effort.

The study team, in conjunction with TxDOT staff, agreed to focus the study on commuters in the area bordered by I-10 (Katy Freeway) on the north, the Westpark Tollway on the south, the Brazos River on the west, and downtown Houston on the east. A map of this section of the city is provided in Figure 1. This section was selected because TxDOT had travel time reliability data that could be used for the study. The target roadways for the study were the Katy Freeway main lanes, the Katy Freeway Managed Lanes (a four-lane, bi-directional, barrier-separated, managed-lanes facility operating in the middle of the freeway with peak period, High-Occupancy Vehicle [HOV] discounts), and the Westpark Tollway. Travel time reliability information was available for all three of these facilities. The study was branded as the West Houston Transportation Study.

Figure 1. This figure presents a map of the Houston, Texas, area. A yellow box is used to identify the study region for the West Houston Transportation Study. It is bordered by I-10 (Katy Freeway) on the north, the Westpark Tollway on the south, the Brazos River on the west, and downtown Houston on the east.

Figure 1. Map. West Houston transportation study region.

Source: Google Maps.

An extension of the study focused on commuters in the area bordered by I-45 (North Freeway) on the west and the Hardy Toll Road on the east from downtown Houston to Conroe. A map of this section of the city is provided in Figure 2. This section was selected because TxDOT had travel time reliability data that could be used for the study. The target roadways for the study were the North Freeway, the North Freeway HOV Lane, and the Hardy Toll Road. Travel time reliability information was available for all three of these facilities. The study was branded as the North Houston Transportation Study.

Figure 2. This figure presents a map of the Houston, Texas, area. A yellow box is used to identify the study region for the North Houston Transportation Study. It is bordered by I-45 (North Freeway) on the west and the Hardy Toll Road on the east from downtown Houston to Conroe.

Figure 2. Map. North Houston transportation study region.

Source: Google Maps.

COLUMBUS, OHIO

The Ohio Department of Transportation (ODOT) maintains and/or monitors 49,250 Interstate, U.S., and State Route lane miles on which 310 million vehicle miles are traveled each day. This equates to the nation's 4th largest Interstate network and 5th highest vehicle miles traveled. Because of this high volume, ODOT has been a strong advocate of travel time reliability information and has a robust program to collect and utilize these data. The following are key aspects of ODOT's TTR capabilities, which played an integral part in the study:

  • As of 2015, ODOT has both historic and real-time data capabilities.
  • Historic data primarily consist of vehicle/cell probe information as available from traffic data provider INRIX.
  • Real-time data are captured along 2,400 centerline miles using Doppler radar from traffic data provider SpeedInfo.
  • Information from both of these sources, along with the corresponding travel time reliability index (TTRI) calculated by ODOT, were used as part of this effort.

The study team, in conjunction with ODOT staff, agreed to focus the study on commuters in the area along the I-71 corridor from downtown Columbus north to US 36. This section was selected because ODOT has access to travel time reliability data that could be used for the study. A map of this section of the region is shown in Figure 3. The study was branded as the North Columbus Transportation Study.

Figure 3. This figure presents a map of the Columbus, Ohio, area. A yellow box is used to identify the study region for the North Columbus Transportation Study, which is the I-71 corridor from downtown Columbus north to US 36.

Figure 3. Map. North Columbus transportation study region.

Source: Google Maps.

DURHAM – CHAPEL HILL – CARRBORO, NORTH CAROLINA

The Durham-Chapel Hill-Carrboro Metropolitan Planning Organization (DCHC MPO) is comprised of an urban area that includes the City of Durham and several towns in Orange County, North Carolina. The Durham metropolitan area has a population of more than 500,000, and the combined Raleigh-Durham statistical area population exceeds two million. The region's growth is tied to the expanding health science, medicine, and university research sectors, which keep the region among the top ten fastest growing areas in the United States. The following are key aspects of the region, which played an integral part in the study:

  • The DCHC MPO has collected transportation data on highway demand, vehicular travel time, bicyclists, pedestrians, and transit services since 2010 on a comprehensive basis, and also has data for particular parameters dating back to 2001.
  • The DCHC MPO's most congested corridors are the interstates, U.S. highways, and major arterials that provide access to the region's major employment centers, including the Research Triangle Park, Downtown Durham, Duke University, and UNC-Chapel Hill. These areas were the target areas for conducting the study in North Carolina.

The study team, in conjunction with DCHC MPO staff, agreed to focus the study on commuters in the area along the I-40 corridor between Raleigh and Durham, which encompasses the Research Triangle Park. A map of this section of the region is shown in Figure 4. The study was branded as the Triangle Transportation Study.

Figure 4. This figure presents a map of the Raleigh-Durham, North Carolina, area. A yellow box is used to identify the study region for the Triangle Transportation Study, which is the I-40 corridor between Raleigh and Durham.

Figure 4. Map. Triangle transportation study region.

Source: Google Maps.
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