Hot Topics is our electronic newsletter highlighting new publications and resources from a variety of sources.
In this issue:
- Spring maintenance expo: low cost, great value
- Roadside vegetation handbook updated
- Making native prairie plants at home in revegetation areas
- Road salt is making state lakes, rivers saltier
- Retroreflectivity resources
- Report series describes low-cost safety strategies
- TZD proceedings online; Web site redesigned
- Centerline rumble strips reduce lane-departure crashes
- Research and resources on local road and bridge funding
- National Journal Group launches transportation blog
- CEAM, Minnesota APWA launch new Web sites
- Web-based training offered for concrete mix design
- Best-selling author of Traffic to give presentation in St. Paul
- Upcoming LTAP workshops
Spring maintenance expo: low cost, great value
If you haven’t already registered for the 2009 Minnesota Spring Maintenance Training Expo, here are a few reasons why you should:
- Minnesota Department of Transportation (Mn/DOT) commissioner Tom Sorel will speak during the opening session.
- Presentations cover a range of topics: job site hazard prevention, healthy trees, truck-weight education, street-sweeping best practices, customer service, sign retroreflectivity requirements, sun safety for outdoor workers, NPDES Phase II best management practices, native plantings, concrete pavement repair, integrated roadside vegetation management, winning work relationships, and disaster response and debris management.
- The cost is low, and you get great value for the dollar.
- Attendance counts toward your Roads Scholar certificate.
- You can meet your peers and swap ideas.
- You can kick the tires of all types of equipment at the exhibits.
The expo takes place on April 14 and 15 in St. Cloud. Sponsors are the Minnesota Department of Transportation, the Minnesota Local Road Research Board, Minnesota LTAP, the Minnesota Street Superintendents Association, and the Minnesota Chapter of the American Public Works Association.
More information and registration.
Roadside vegetation handbook updated
Maintaining roadsides for safety and aesthetics is an important issue for all levels of government throughout Minnesota. In 2000, the Minnesota Local Road Research Board (LRRB) published the Best Practices Handbook on Roadside Vegetation Management, which served as a valuable resource for maintenance and engineering staff and was used widely in Minnesota and other states. (Minnesota LTAP assisted with the handbook’s production.) The handbook’s popularity, as well as the availability of new information from recent research, led the LRRB and Mn/DOT to publish an update of the handbook last year.
The 2008 edition retains all information from the original that is still accurate. It also includes a new chapter—“Managing Roadside Vegetation for Wildlife and Vehicle Safety”—that reflects recent Mn/DOT research about roadside habitats and their effects on driver safety. The new chapter’s primary conclusion is that roadside habitats can be managed to balance biological diversity and safety by selectively reducing woody vegetation without entirely removing grass habitats.
The main conclusion from the handbook is that successful roadside vegetation management depends on an integrated approach. This includes a wide variety of best management practices to address the many issues involved.
Kathy Schaefer, the instructor of the Circuit Training and Assistance Program (CTAP), was a member of the technical advisory panel for the handbook update. She is using the handbook in CTAP classes in May. The handbook will also be used in a session on integrated roadside vegetation management at the Minnesota Spring Maintenance Training Expo on April 15.
Read a technical summary of the project.
Download the handbook (report 2008-20; 4.8MB).
Making native prairie plants at home in revegetation areas
The findings from a recent study at the University of Minnesota Sandplain Research Farm may help transportation agencies re-introduce native prairie plant species along roadways. Researchers investigated techniques of rhizobial inoculation to support the growth of legumes and improve soil nitrogen levels.
The team tested several soil inoculation techniques, monitoring plots to determine which techniques produced the best nitrogen levels and the most legume growth. Inoculation with granular peat inoculant emerged as the recommended technique, and the findings suggested that it should be applied more heavily than it is currently in Minnesota.
Improved Methodologies for the Inoculation of Prairie Legumes in Roadside/Revegetation Settings (Mn/DOT 2008-48) is available from the Center for Transportation Studies (CTS) Web site.
Road salt is making state lakes, rivers saltier
Road salt residue is making Minnesota’s lakes and rivers saltier, according to new research from the University of Minnesota’s St. Anthony Falls Laboratory. The increasing salinity of our waters has an impact on aquatic life, and it could lead to significant problems with ground water in the long term.
Watch the U of M News Service video.
Retroreflectivity resources
The Federal Highway Administration (FHWA) released new federal retroreflectivity standards in January 2008. This mandate requires state and local agencies to assess the signs on their roads and develop a replacement plan within four years of the final ruling; replace non-compliant warning and regulatory signs within seven years of the final ruling; and replace guidance and street name signs within 10 years of the final ruling.
A session at the Minnesota Spring Maintenance Training Expo on April 14 will address retroreflectivity requirements. Also, the Circuit Training and Assistance Program (CTAP) will offer sign retroreflectivity training in June 2009. Details will be available on the Web soon.
Following are several other retroreflectivity resources.
NACE Web site, grant program
Last year the National Association of County Engineering (NACE) launched an education Web site and companion grant program site to aid members in replacing traffic signs to meet the new federal retroreflectivity standards. The specially prepared education site assembles and publishes background information, best practices, and current literature from the transportation community.
The grant program allows counties to apply for one-time grants to significantly reduce the cost of their effort to improve reflective brightness of traffic signs. Applications will be received through June 30, 2009 (extended from December 31, 2008). NACE members can apply for the grant program by visiting the NACE Web site “Members Only” page.
Maintaining traffic sign retroreflectivity
One of the concerns expressed by agency personnel responsible for conformance with the new retroreflectivity minimums is the potential increase in tort exposure. Therefore, FHWA developed methods for maintaining retroreflectivity that, when implemented as intended, provide agencies with a flexible means of conforming with required minimum retroreflectivity levels and offer protection from potential tort claims. After completing an engineering study, agencies also can use other methods to maintain signs at the required minimum retroreflectivity levels. The information in this report can help DOTs determine which retroreflectivity maintenance method or combination of methods best suits their needs.
Methods for Maintaining Traffic Sign Retroreflectivity (Publication No. FHWA-HRT-08-026)
Retroreflectivity levels for blue, brown traffic signs
In 2003, the FHWA published research recommendations for minimum maintained retroreflectivity (MR) levels for most traffic signs but excluded white-on-blue and white-on-brown signs. The recommendations were based on conditions representing dark, rural environments. A new report describes the research activities and findings related to the development of recommendations for MR levels for white-on-blue and white-on-brown signs. The report also includes recommendations from an investigation related to MR levels needed for complex visual conditions, including glare from oncoming headlamps and fixed roadway lighting.
Minimum Retroreflectivity Levels for Blue and Brown Traffic Signs (Publication No. FHWA-HRT-08-029
Report series describes low-cost safety strategies
As part of its strategic highway safety effort, the Federal Highway Administration (FHWA) organized a pooled-fund study involving 26 states to evaluate low-cost safety strategies. The following reports describe the strategies studied.
Safety Evaluation of Increasing Retroreflectivity of STOP Signs (Publication No. FHWA-HRT-08-041)
This strategy aims to reduce the frequency of crashes related to drivers being unaware of STOP signs at unsignalized intersections. The report states that this strategy has the potential to reduce crashes cost-effectively, particularly at lower-volume intersections.
The goal of this strategy is to reduce the frequency of crashes involving a turning vehicle, which could be classified as head-on or rear-end crashes. The researchers concluded that installations of these types of lanes can be a cost-effective treatment for two-lane rural roads, especially those with a high frequency of rear-end collisions involving a vehicle trying to make a turn.
Safety Evaluation of STOP AHEAD Pavement Markings (Publication No. FHWA-HRT-08-043)
The goal of this strategy is to reduce the frequency of crashes related to drivers being unaware of stop control at unsignalized intersections. Based on the estimated safety effectiveness of STOP AHEAD pavement markings, the researchers concluded that the necessary crash reduction to obtain a 2:1 benefit-cost ratio is easily achieved. Therefore, this strategy has the potential to reduce crashes cost effectively at unsignalized intersections, particularly at three-legged and AWSC intersections.
The purpose of this strategy is to reduce the frequency of crashes related to drivers being unaware of stop signs at unsignalized intersections. Researchers studied three types of flashing beacons—intersection control beacons, beacons mounted on STOP signs, and actuated beacons—at stop-controlled intersections. The economic analysis indicates that standard flashing beacons and some of the actuated ones (that is, the less expensive beacons) are economically justified, but that a benefit-cost ratio of 2:1 might not be achievable for the more expensive beacon types.
TZD proceedings online; Web site redesigned
A proceedings of the 2008 Toward Zero Deaths conference is online. Some of the session topics of interest to local agency personal include:
- Minnesota’s Strategic Highway Safety Plan
- Signs and Stripes for Safety Sake
- Intersection Collision Prevention Overview
In addition, many of the presenters’ PowerPoints are posted.
Toward Zero Deaths is a multiagency partnership that includes representatives from Mn/DOT, the Minnesota Department of Public Safety, the Minnesota State Patrol, the Federal Highway Administration, and the Center for Transportation Studies (CTS). The conference was hosted by the CTS and sponsored by Mn/DOT, the Department of Public Safety, and the Minnesota TZD program.
The redesigned TZD Web site was launched at the conference. The new site features year-to-date tracking of traffic fatalities, a gateway to safety statistics, more user-friendly navigation, and expanded coverage of topics included in the Minnesota Strategic Highway Safety Plan. The site also offers tips for how groups can organize to identify and help find solutions to the traffic safety problems in their communities.
Centerline rumble strips reduce lane-departure crashes
The results of an Arizona Department of Transportation (ADOT) study, "Safety Enhancement Evaluation of Ground-In Centerline Rumble Strips," suggest that centerline rumble strips can be a cost-effective solution to reduce crashes on rural roads. Further, ADOT's experiences, observations, and lessons learned could help other agencies that are considering CLR installations within their own jurisdictions.
The study and its findings are described in “The Sound of Safety,” an article in the January/February 2009 issue of Public Roads. Public Roads is the bimonthly magazine of the Federal Highway Administration (FHWA).
Research and resources on local road and bridge funding
To help Minnesota’s public works officials better understand potential funding, Mn/DOT’s Research Services Section sponsored a study designed to identify the most relevant and useful research on transportation finance issues.
The report — A Synthesis of Research andResources on Local Road andBridge Funding for Local PublicWorks Officials (2007-16) (pdf) — not only highlights potential funding sources and information, but categorizes those sources into three broad groups: funding system/options, advocacy tools, and benefits of local transportation infrastructure investments.
National Journal Group launches transportation blog
The National Journal Group has launched a transportation blog. It is one of several “expert blogs” in which a panel of insiders discusses key issues.
National Journal Group is a leading source of nonpartisan reporting on the current political environment and emerging policy trends.
CEAM, Minnesota APWA launch new Web sites
The City Engineers Association of Minnesota (CEAM) has redesigned its Web site.
The site includes the CEAM Forum, maintained by the League of Minnesota Cities. The forum is an enhanced version of the list-serves the League has operated for several years. Forums allow participants to easily view past messages, which are viewable in the forum format for one year from the posting date.
Other pages on the CEAM site contain information about careers, committees, training and events, and scholarships.
The Minnesota Chapter of the American Public Works Association also has a new and improved Web site. Please check it out.
Web-based training offered for concrete mix design
Online training on Mix Design Principles (FHWA-NHI-134087) is now available.
The training was developed by the Transportation Curriculum Coordination Council (TCCC) in partnership with the National Highway Institute (NHI) to review integrated materials and construction practices for concrete pavement. It is the first training of its kind offered by NHI. This course is recommended for the Transportation Curriculum Coordination Council levels II through IV.
The course discusses theoretical, laboratory, and field testing to determine the portland cement concrete mix that will achieve the best possible durability, strength, constructability, economy, and uniformity. This module is part of a curriculum from the Integrated Materials and Construction Practices for Concrete Pavement manual developed through the National Concrete Pavement Technology Center at Iowa State University. Other modules will be available as they are converted to Web-based training.
Register online at www.nhi.fhwa.dot.gov.
Best-selling author of Traffic to give presentation in St. Paul
Tom Vanderbilt, author of the New York Times best seller Traffic: Why We Drive the Way We Do (and What It Says About Us), will give the Center for Transportation Studies (CTS) Spring Luncheon presentation on May 19. The luncheon is part of the 20th Annual CTS Transportation Research Conference, which will be held at the Sheraton Hotel in Bloomington May 19 and 20.
In his most recent book, Vanderbilt explores some of the remarkable dynamics of traffic. For example, he asks, would you be surprised that road rage can be good for society? Or that most crashes happen on sunny, dry days? That our minds can trick us into thinking the next lane is moving faster? Or that you can gauge a nation’s driving behavior by its level of corruption? At the luncheon, Vanderbilt will share the complex web of physical, psychological, and technical factors that explain how traffic works, why we drive the way we do, and what our driving says about us.
For more information, contact Sara Van Essendelft, 612-624-3708, cceconf5@umn.edu.
Upcoming LTAP workshops
Minnesota Truck-Weight Compliance Training
Motor-Grader Operator Training
Also, the Circuit Training and Assistance Program (CTAP) will offer sign retroreflectivity training in June 2009. Details will be available on the Web soon. CTAP is the mobile arm of Minnesota LTAP.