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In some states (e.g., Texas), frontage roads have been a design solution for providing access along rural freeways and access-controlled principal arterials. In rural and lesser-developed urban areas, the frontage roads are usually operated as two-way facilities because of relatively long distances between interchanges. As areas become more urban and the adjacent land is developed, traffic volumes increase, and as interchange spacing decreases, it becomes desirable to convert the frontage roads to one-way operation. There is a need to objectify safety impacts of frontage road conversion, and business and property owners are often concerned with economic impacts related to access, business activity, and property values. Recognizing these needs and concerns, the Texas Department of Transportation contracted with the Texas A&M Transportation Institute to investigate the safety and economic impacts of converting two-way frontage roads to one way. Researchers investigated eight sites throughout Texas: both conversion sites and comparison sites that remained two way. Researchers developed 12 crash modification factors by crash severity and crash type for frontage road conversion. A sample application is provided in this paper. To assess economic impacts, researchers obtained parcel-level appraisal data and found overall increases in appraised values. Researchers surveyed business owners and managers and customers. Researchers found that business owners and managers are typically concerned with access, gross sales, and ramp and interchange locations and spacing. Finally, researchers identified lessons learned with the crash data for those performing safety analyses.

The Highway Capacity Manual provides a means for evaluating level of service on freeways, highways, and urban streets. Presently, the Highway Capacity Manual methodology is not able to evaluate level of service on freeways with free-flow speeds greater than 75 mph or multilane highways with free-flow speeds greater than 60 mph, and many states now have facilities with posted speed limits that exceed these free-flow speeds. Recent research, conducted by the Texas A&M Transportation Institute (TTI), developed speed prediction equations for uninterrupted flow facilities with higher posted speed limits. From these equations, this paper develops procedures for calculating free-flow speed on facilities with higher posted speed limits and develops methods for estimating level of service on freeways with free-flow speeds up to 85 mph and multi lane highways with free-flow speeds up to 80 mph. For freeways, the recommendations call for utilizing the TTI speed prediction equations to calculate free-flow speed and using the calculated free-flow speeds to determine level of service from speed–flow curves developed within this paper. For multilane highways, recommendations call for utilizing the TTI speed prediction equations to calculate base free-flow speed, which is part of the equation for calculating free-flow speed, and then using the calculated free-flow speed to determine level of service from speed–flow curves developed within this paper. To aid practitioners, step-by-step procedures are provided for applying the TTI speed prediction equations within the Highway Capacity Manual methodology.

This study evaluated the effect of yellow rapid flashing beacon characteristics on the ability to detect objects located behind a sign during a closed-course driving study sponsored by FHWA. For the analysis focusing on object detection distance, the results indicated that certain study assemblies were associated with shorter object detection distances. During the day, the object detection distance was shorter for objects behind an assembly with two rectangular beacons below the sign (R-B), as opposed to other beacon arrangements, such as two rectangular beacons above the sign and two circular beacons below or above the sign. At night, the detection distance to an object was shorter behind an assembly with R-B when compared with an assembly with two 12-in. circular beacons below the sign. These findings indicated that characteristics of the R-B, such as the light intensity or the location of the beacons, might negatively affect the driver's ability to see an object. For the analysis focusing on the accuracy of detecting objects, which considered the number of objects missed by the participants, the location of the beacons (above or below the sign) was significant during the day but not at night. During the day, participants were less likely to miss an object when the beacons were above the sign.

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