LTAP news briefs
The Washington State Local Technical Assistance Program (LTAP) is a partnership between WSDOT's Local Program Division and FHWA, providing training opportunities and a coordinated technology transfer program for local agencies in Washington State. LTAP offers courses directly targeting the training needs of local agencies receiving Federal funding.
Below are news items of interest to our local agencies and partners.
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Statewide Roadway Action Plan Leads to Crash Analysis at District Level
In their Statewide Roadway Departure (RwD) Action Plan, the Kentucky Transportation Cabinet (KYTC) recommended the installation of rumble strips and high friction surface treatment (HFST) primarily on State roads with functional class “Collector” or higher. The State evaluated these countermeasures and determined a benefit-cost ratio for center line and edge line rumbles strips up to 65:1 and up to 44:1 for HFST. These findings led KYTC to systematically integrate rumble strips into the State’s resurfacing schedule.
KYTC then developed a suite of safety performance functions (SPFs) used in network screenings for proven countermeasures, such as cable median barrier and HFST. This tailored network screening uses crash types and facility types that correlate with where these countermeasures are most effective (e.g., wet weather curve crashes for HFST). This allows KYTC to eliminate non-RwD crash types to focus on locations with the most potential for safety improvement.
KYTC is building on the success of its Statewide RwD Action Plan with an ongoing crash analysis at the District level. These studies will investigate each District’s RwD safety challenges using a systemic approach and the State-specific SPFs to identify potential projects. A systemic approach is a proactive, cost-effective means of addressing where crashes are expected in the future. The systemic approach doesn’t replace, but complements, the need for site-specific projects. KYTC has a goal to allocate HSIP funds equally between systemic and site-specific projects across the State
High Friction Surface Treatments Effectively Reduce Crashes
In 2012, Thurston County in Washington State conducted a data-driven safety analysis to identify and prioritize potential safety projects that would be eligible for Highway Safety Improvement Program (HSIP) funds. The data showed that 27 percent of fatal and severe crashes involved skidding or out of control vehicles. The data also revealed that wet and icy pavements contributed to 47 percent of crashes. These patterns led the County to identify high friction surface treatment (HFST) as an effective solution for crash reduction. The County used risk factors for arterial and collector roads to prioritize locations for HFST, including posted speed limit of 50 mph or more, traffic volumes, presence of horizontal curves, and shoulder type and width.
In 2016, the Washington State Department of Transportation awarded Thurston County more than $2 million for HFST at 29 locations, which were installed in 2018. In the three years following installation, the HFST projects at horizontal curves have resulted in substantial reductions in average crashes per year, including 46 percent for total lane departure crashes, 70 percent for wet lane departure crashes, and 100 percent for fatal and serious injury lane departure crashes.
High-Friction Surface Treatment EDC Storyboard- Helping Drivers Get a Grip
EDC storyboards share innovation deployment stories in an interactive digital slideshow that incorporates images, video, and graphics to create a highly visual experience for our readers.
Our latest storyboard comes from the focus on reducing rural roadway departures (FoRRRwD) team and discusses benefits of high-friction surface treatment as a countermeasure for rural roadway crashes and gives some crash statistics that may surprise you. This relatively inexpensive treatment can reduce crashes on wet curves by over 80 percent!
EDC Safety Summit Series Begins Soon
Safety innovations have been a cornerstone of the EDC program since 2011, resulting in their rapid deployment and institutionalization, and the upcoming EDC Safety Summit Series will build on that momentum.
September 1 will focus on Safe Transportation for Every Pedestrian (STEP) and will include opportunities to discuss this topic with peers and establish relationships that can boost success now and in the future.
Register for the summit, which will take place from 10 am to 2 pm ET each day and is open to all State, local, and tribal stakeholders. Participants can join for one or all five Wednesdays. Contact Karen King, FHWA Virginia Division, for additional information. 8/21
Innovation of the Month: Targeted Overlay Pavement Solutions
More than 40 percent of major roads in the United States are in poor or mediocre condition. The U.S. Department of Transportation’s 2015 Conditions & Performance Report estimated that America needs more than $800 billion to fix highways and bridges. By enhancing overlay performance in priority locations, State and local highway agencies can help ensure safer, longer-lasting roadways.
Improved overlays are now available for both asphalt and concrete pavements that enable agencies to provide long-life performance under a wide range of traffic, environmental, and existing pavement conditions. FHWA’s Targeted Overlays Pavement Solutions initiative, known as TOPS, encourages agencies to maximize their investment by using overlays in high-maintenance locations such as primary or interstate pavements, intersections, bus lanes, ramps, and curves.
The TOPS team is promoting eight asphalt overlays and two types of concrete overlays that offer many benefits. These overlays reduce maintenance, maximize previous investments through extended service life of pavement structures, and reduce user delays (fewer work zones). In addition, certain overlays increase skid resistance, improve resiliency in flood-prone areas, reduce splash and spray, and reduce noise.
- Asphalt rubber gap-graded (PDF 470KB)
- Crack attenuating mix (PDF 454KB)
- Enhanced friction overlay (PDF 382KB)
- Open-graded friction course (PDF 386KB)
- Highly modified asphalt (PDF 339KB)
- Stone matrix asphalt (PDF 392KB)
- High-performance thin overlay (PDF 981KB)
- Ultra-thin bonded wearing course (PDF 459KB)
Concrete on Asphalt
Concrete on Concrete
The TOPS team provides technical assistance to help transportation agencies select the right overlay product for the right location. The team has created fact sheets on different types of overlays and will release several case studies and how-to documents later this year. View the TOPS EDC overview video and stay tuned for information on additional webinars and workshops.
To learn more about Targeted Overlay Pavement Solutions, contact Tim Aschenbrener (asphalt) and Sam Tyson (concrete), EDC-6 team co-leads or visit the team's EDC website. To stay connected with the TOPS team, join their mailing list to receive updates and new resources as they become available. 8/21