U.S. Department of Transportation
Federal Highway Administration
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
This magazine is an archived publication and may contain dated technical, contact, and link information.
|Publication Number: FHWA-HRT-13-003 Date: March/April 2013|
Publication Number: FHWA-HRT-13-003
Issue No: Vol. 76 No. 5
Date: March/April 2013
Along the Road is the place to look for information about current and upcoming activities, developments, trends, and items of general interest to the highway community. This information comes from U.S. Department of Transportation (USDOT) sources unless otherwise indicated. Your suggestions and input are welcome. Let's meet along the road.
Researchers at the Federal Highway Administration (FHWA) are developing a device to field-test for bridge scour. The study is underway in the J. Sterling Jones Hydraulics Research Laboratory at FHWA’s Turner-Fairbank Highway Research Center in McLean, VA. The goal of the project is to address the need for more reliable, accurate, and practical methodologies to estimate the potential for soil erosion around bridge foundations.
Scour, the erosion of bridge foundations by water, is the most common cause of bridge failure in the United States and contributes significantly to construction and maintenance costs. Because of time and cost constraints, most methodologies to predict scour do not account for the wide range of naturally occurring soils and their resistance to erosion and scour.
Researchers envision the field device to be a closed recirculation and filtering system that will operate in both wet and dry conditions while minimizing environmental impacts. Once completed, the device will be used for foundation analysis and design in a manner similar to soil borings, with testing conducted at proposed foundation locations across the channel and flood plain area at sites of new or replacement bridges.
|Researchers are developing the device shown here to test for scour at bridge sites. The prototype consists of an outer pipe column with an inserted cutting head, which erodes the soil material inside the outer column, replicating the effects of natural scour.|
In testing, the researchers found that a lab-scale device consisting of an outer circular pipe column with a concentric cutting head centered within the column has performed well. Following lab testing, a prototype will be produced for field calibration. If results are favorable, the researchers expect that the device can be used to test the scour potential of a wide range of soils types to depths of 65.5 feet (20 meters).
For more information, visit www.fhwa.dot.gov/research/resources/bridge_scour_test.cfm or www.pooledfund.org/Details/Study/438.
As it rehabilitates its aging roadways, the Virginia Department of Transportation (VDOT) is saving time and money by combining methods of pavement recycling. The agency rebuilt a 3.7-mile (6-kilometer), two-lane section of southbound I–81 near Staunton, VA, by recycling existing road material and using it in the new pavement structure. The I–81 project marked the first time cold in-place recycling, cold mobile-plant recycling, and full-depth reclamation were used together on an interstate project in the United States, although other States have used the techniques separately. The $10.16 million project took about 8 months to complete. VDOT estimates that using conventional pavement construction would have cost about three times as much and taken about 2 years.
|Here, on I–81 in Virginia, workers prepare the underlying base material for a rehabilitation project that used full-depth reclamation. The process involves removing the existing asphalt pavement, pulverizing and then stabilizing it with an additive, and reapplying the material to the roadway.|
The project increased safety for drivers and road workers because it reduced work zone congestion. VDOT also used a novel traffic management plan: While one lane on I–81 was under construction, large trucks traveled on the other lane and cars were detoured onto U.S. 11, away from the construction. Onroad, Web-based, and other communications tools alerted motorists about the construction and detour.
VDOT won the 2012 Recycling Award in the cold in-place category from the Asphalt Recycling & Reclaiming Association and Roads & Bridges magazine. Winners were selected based on the amount of recycled pavement materials used, cost savings, and project challenges.
The Alaska Department of Transportation and Public Facilities recently approved a highway specification permitting the use of recycled, crushed glass in gravel used to strengthen subsurface layers of highway and airport pavements. The specification, initiated by the transportation department and the nonprofit Alaskans for Litter Prevention and Recycling, identifies a process for repurposing glass from household waste as a durable and long-lasting construction material.
Types of glass products allowed for recycling under the specification include food and beverage containers, some dishes, and glass from building windows. The recycling process turns the glass into a product that looks like shiny, pea-sized gravel and feels smooth like worn beach glass. The transportation department will use the recycled glass only in the base layers. Using crushed glass will decrease the amount of this material going into landfills, while reducing the transportation department’s need for rock and gravel used to strengthen roads. The department expects to see a cost savings by using the locally processed and stockpiled recycled glass over the traditional aggregate that must be transported via rail. Cost and quality data will be collected as projects incorporate the glass.
Alaska Department of Transportation and Public Facilities
The California Department of Transportation (Caltrans) recently began deploying intelligent transportation systems to counter congestion in the San Mateo metropolitan area. The $35 million San Mateo Smart Corridor project, scheduled to be completed by fall 2013, will apply the latest traffic management technology along 20 miles (32 kilometers) of El Camino Real from San Bruno to Menlo Park and on local streets in San Mateo County.
A planned fiber-optic communication system will connect to Caltrans’ Transportation Management Center in Oakland and 10 cities in San Mateo County. Electronic message signs will guide motorists through detours during freeway incidents, sensors will provide information about the volume of traffic at specific locations, and closed-circuit television cameras will enable road managers to monitor traffic flow and determine the most effective ways to reroute motorists during major congestion.
|Workers prepare to install colorful fiber-optic cable on El Camino Real in San Mateo County, CA.|
One of the major benefits is that the project will link more than 250 State and local traffic signals. With this network, road managers can adjust signal timing remotely to better control traffic flow during incidents, eliminating the need to drive to individual signals to make adjustments. The project also will improve communication and coordination among emergency responders, local agencies, and Caltrans because they will all have access to the same information.
The American Association of State Highway and Transportation Officials (AASHTO) and ASTM International (formerly known as the American Society for Testing and Materials) recently signed an agreement on standards that solidifies coordination between the two organizations in the areas of highway construction, safety, maintenance, and sustainability.
AASHTO’s then Executive Director John Horsley and ASTM President James A. Thomas signed the agreement, which now serves as the basis for cooperation on the development and publication of voluntary standards for highway construction in the United States and around the world.
AASHTO’s transportation experts have contributed to more than 125 volumes of standards and guidelines related to the design, construction, maintenance, operation, and administration of highways, bridges, and other transportation facilities. Likewise, ASTM’s technical committees have developed more than 1,000 standards that address the needs of road construction and transportation. The agreement will help the organizations avoid duplication of efforts, streamline processes, and respond to industry needs efficiently and collaboratively, saving time and resources.
The National Highway Traffic Safety Administration (NHTSA) recently released updated 2011 data on highway traffic fatalities. Analysts report that highway deaths fell to 32,367 in 2011, the lowest level since 1949 and a 1.9 percent decrease from the previous year. The 2011 data show that the downward trend in fatalities in recent years continues, and overall fatalities since 2005 have decreased 26 percent.
Although Americans drove fewer miles in 2011 than in 2010, the nearly 2 percent drop in roadway deaths outpaced the corresponding 1.2 percent decrease in vehicle miles traveled. In addition, information in the Fatality Analysis Reporting System shows that 2011 also saw the lowest fatality rate ever recorded, with 1.10 deaths per 100 million vehicle miles traveled in 2011, down from 1.11 deaths per 100 million vehicle miles traveled in 2010.
Deaths involving drunk drivers dropped 2.5 percent in 2011, but the number of people killed in crashes involving distraction rose by 1.9 percent from 2010 to 2011. NHTSA officials note that this apparent increase may be attributed in part to growing awareness and reporting of distraction as a contributing factor.
For more information or to download the report, visit www-nrd.nhtsa.dot.gov/Pubs/811701.pdf.
The Pedestrian and Bicycle Information Center (PBIC) released the results of a comprehensive national study of bike-sharing programs. The report, Bike Sharing in the United States: State of the Practice and Guide to Implementation, provides guidance on how to plan, implement, and measure the success of bike-share programs in communities of all sizes.
The guide can serve as a resource for a broad audience, including transportation planning professionals and public officials considering implementing a bike-share program. The study focused on a range of municipal programs that local jurisdictions have funded, managed, administered, and permitted.
Based on an analysis of 12 existing and planned programs across the country, the guide explores the evolution and expansion of bike sharing in the United States. Further, it defines success factors, describes a step-by-step approach to implementing a program, documents costs, examines different models for funding, and describes metrics for monitoring and evaluating success.
For more information and to download the guide, visit www.bicyclinginfo.org/bikeshare.
New videos on FHWA’s Highways for LIFE Web site feature projects funded through the Technology Partnerships program. The goal of Highways for LIFE is to advance longer lasting highway infrastructure using innovations to increase safety and efficiency. The Technology Partnerships program helps industry develop promising prototypes into market-ready products that can improve highway quality, enhance safety, or reduce congestion.
|A video on FHWA’s Highways for LIFE Web site demonstrates use of the bridge bent system for seismic regions. Here, workers are setting the cap beam.|
The six videos run about 3 to 5 minutes each and provide overviews and demonstrations of various technologies and processes. Examples of the videos include “Bridge Bent System for Seismic Regions,” “Full Depth UHPC [Ultra-High Performance Concrete] Waffle Bridge Deck Panels,” “Automated Pavement Marker Placement System,” and “Aggregate Image Measurement System (AIMS2).”
For more information and to view the videos, visit www.fhwa.dot.gov/hfl/commtool.cfm.