Link travel times are one of the most widely used and valuable measurements of congestion. Travel time measures are compatible with multimodal analyses and are understood by nontechnical audiences, yet are rigorous enough for technical analyses by transportation engineers and planners. The “average” car and floating car techniques are the most widely used travel time–based measures. Although there are cost, safety, and data limitation problems associated with collecting travel time data manually, the use of computer-aided travel time technology solves most of these problems. Detailed speed, time, and distance information can be safely collected in up to 0.1-sec intervals for a reasonable cost. The consistent format of the computer data lends itself to an automated analysis process. The development and benefits of using computer-aided travel time data collection techniques using distance-measuring instruments (DMI) and laptop computers are discussed. Automated analysis techniques and developmental software can produce results such as speed profiles, average speeds, level of service, and vehicle accelerations. Current and future research on air quality methods, fuel consumption information, and planning model potential is also presented.

The goal of the access management study of the Houston–Galveston Area Council in Texas, was to examine the effects of recommended improvements before, during, and after project implementation in three areas: operations (traffic flow, intersection delay, and corridor delay), safety (crash frequency, crash rates, and comparisons with state averages), and economic (comparison of taxable sales receipts and control for other economic factors occurring during those times). This paper focuses on an economic assessment that was not addressed by previous studies and on local concerns about the economic impacts of access management. This economic evaluation methodology focused on collection and analysis of taxable sales data to examine possible changes in business activity before, during, and after any implemented access management improvements for various classes of businesses in the corridor study areas. Three corridors, consisting of principal arterials in a large urban area with retail and residential development, were studied. The trends from the three corridors studied suggested that business sales increased at a greater rate along these corridors than in the adjacent control zip code analysis zone. The data showed that overall economic activity in the three corridors was not negatively affected by the implementation of access management. Although confounding factors (Hurricanes Rita and Ike and the economic recession of 2007 to 2009) were in play in an examination of economic impacts during these types of projects, the results of this evaluation indicated that corridor economic activity typically remained steady, and in many cases, increased after access management projects were implemented.

Several steps in the planning, execution, and evaluation of the I-45 Pierce Elevated reconstruction in Houston provide a strong framework for preparing for projects that affect critical links in the nation’s transportation system. These elements include preconstruction traffic modeling, public information, and data collection before and during each phase of construction. Traffic modeling helped to prepare for construction by first developing delay numbers for the estimated user cost used in the A + B bidding. Second, preconstruction modeling identified bottlenecks that were temporarily remediated at strategic locations. Finally, modeling provided speed and travel time data used in mounting a public information campaign. Data collection and monitoring of traffic conditions immediately before, immediately after, and a few weeks after construction began provided an immediate picture of traffic conditions and identified problem locations that could be corrected during construction. A critical public information campaign was undertaken using television, radio, newspaper articles, billboards, fliers, and variable message signs. Each of these provided advance warning to motorists in the weeks before construction began and variable message signs, radio, and the Internet were used to provide real-time information during construction. Preparations for the Pierce Elevated reconstruction went beyond standard procedures and planning typically used for major construction projects. Although engineers have traditionally been designers as well as project managers, they will be called on more to become brokers of information that will allow the public to use the transportation network in the most time- and cost-effective manner under adverse construction conditions.

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Many state departments of transportation (DOTs) often use a subjective evaluation program to assess the condition of their roadway assets. Because pavement markings are typically only a small part of these assessment programs and because visual assessment is subjective, the ratings may not always be accurate in identifying roadways with inadequate markings. This research sought to evaluate the accuracy of visual assessments of pavement markings. The Texas Transportation Institute conducted two separate nighttime evaluations as part of a Texas DOT research project. The first evaluation was conducted on open roads, and the second was conducted on a closed experimental course. Subjective rating data were collected on pavement markings by several DOT evaluators. To analyze the data, researchers compared retroreflectivity measurements with subjective ratings of the pavement markings. For the first night study, the average subjective rating of each marking compared with the measured retroreflectivity resulted in a logarithmic R2 value of .818. The second night study resulted in a logarithmic R2 value of .821 before training and .809 after training. The data were also evaluated by marking color and evaluator experience level. Researchers found that average subjective ratings showed acceptable correlation with retroreflectivity measurements, but ratings could show large variations between individuals. The researchers recommend that subjective assessment be considered a viable option for evaluating pavement markings. They also recommend that for any assessment the evaluator be well trained or multiple evaluators be utilized, with reported ratings averaged to provide reliable results.