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July/August 2005
Communication Product Updates
Compiled by Zac Ellis of FHWA's Office of Research and Technology ServicesBelow are brief descriptions of products recently published online by the Federal Highway Administration's (FHWA) Office of Research, Development, and Technology. Some of the publications also may be available from the National Technical Information Service (NTIS). In some cases, limited copies are available from the Research and Technology (R&T) Product Distribution Center.
When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS Web site at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703–605–6000
Toll-free number: 800–553–NTIS (6847)Address requests for items available from the R&T Product Distribution Center to:
R&T Product Distribution Center, HRTS-03
Federal Highway Administration
9701 Philadelphia Court, Unit Q
Lanham, MD 20706
Telephone: 301–577–0818
Fax: 301–577–1421For more information on research and technology publications from FHWA, visit the Turner-Fairbank Highway Research Center's (TFHRC) Web site at www.tfhrc.gov, FHWA's Web site at www.fhwa.dot.gov, the National Transportation Library's Web site at http://ntl.bts.gov, or the OneDOT information network at http://dotlibrary.dot.gov.
Characteristics of Emerging Road and Trail Users and Their Safety
Publication No. FHWA-HRT-04-104FHWA undertook this study to clarify the operational characteristics of an increasingly diverse group of trail and other nonmotorized transportation users. Three “Ride for Science” data collection events were conducted to obtain the physical trail dimensions, turning capabilities, lateral operating space, acceleration, speed, and stopping sight distance that trail users encounter. The results confirmed the diversity in the operating characteristics of road and trail user types. Below are highlights from the report’s findings:
Sweep width for inline skaters. The sweep width of inline skaters falling in the 85th percentile of all sweep width measurements was 1.5 meters (4.9 feet), which actually is wider than the AASHTO recommended width for bike lanes.
Design speed. Out of all types of trail users, recumbent bicyclists had the highest observed 85th-percentile speed, clocking in at 29 kilometers per hour (18 miles per hour) —less than the American Association of State Highway and Transportation Officials’ (AASHTO) minimum design speed.
Horizontal alignment. Most users did not reduce their speeds for turning radii greater than 16 meters (52.5 feet).
Stopping sight distance. A recumbent cyclist falling in the 85th percentile of measured stopping sight distances required a distance of only 32.7 meters (107.3 feet) on wet pavement—less than the AASHTO design speed.
Vertical alignment and crest vertical curves. Recumbent bicyclists required a crest vertical curve 46.7 meters (153 feet) in length—less than the AASHTO value.
Signal clearance intervals. Five-second clearance intervals did not provide sufficient time to clear a five-lane, 18.3-meter (60-foot) wide intersection for users with clearance times falling at the 85th percentile or higher.
Characteristics of Segway® users. Many characteristics of Segway human transporter users were comparable with those of other emerging trail users.
These findings suggest that design guidelines may need to be revised to incorporate the needs of emerging trail users. The results of this study can be used to help design professionals adequately design roadway and shared-use path facilities to meet the operational and safety needs of this growing group of users.
To view the report, visit www.tfhrc.gov/safety/pubs/04104/roadstechbrief.pdf.
Long-Term Pavement Performance (LTPP) Year in Review 2004
Publication No. FHWA-HRT-04-125In 2004 the Long-Term Pavement Performance (LTPP) program continued working toward optimizing the public’s investment in the highway system by providing the information, data, and products that highway engineers and managers need to design, build, maintain, and manage more cost-effective and better performing roads. This report outlines LTPP’s 2004 program area accomplishments and how the extension of the Transportation Equity Act for the 21st Century impacted the LTPP program.
To view the report, visit www.tfhrc.gov/pavement/ltpp/reports/04125/04125.pdf.
Guide for Curing of Portland Cement Concrete Pavements
Publication No. FHWA-RD-02-099This document provides guidance on the details of concrete curing practices as they pertain to the construction of portland cement concrete pavements. The guide is organized around the major steps involved in curing pavements—curing immediately after placement (initial curing), curing during the period after final finishing (final curing), terminating the curing process, and evaluating the effectiveness of the curing process. The publication also offers specific information on selecting curing materials and procedures, analyzing concrete properties and jobsite conditions, and adjusting the curing practice to account for specific project conditions.
Other Articles in this issue:
Safety Scans—A Successful Two-Way Street
Multistate Endeavor to Address Premature Pavement Distress
Looking to Load and Resistance Factor Rating
Achieving Concrete's Full Potential
July/August 2005 · Vol. 69 · No. 1
