Project Details
06/01/16
03/22/19
Midwest Transportation Center
Missouri Department of Transportation
University of Illinois
Researchers
William G. Buttlar
James Meister
About the research
A comprehensive laboratory and field investigation was carried out to evaluate the performance of recycled asphalt mixtures in Missouri by researchers at the University of Missouri-Columbia, in collaboration with the Missouri Department of Transportation and the Midwest Transportation Center.
Eighteen field sections were evaluated, including a number of sections from the recent Long-Term Pavement Performance (LTPP), Special Pavement Sections (SPS-10) project in Osage Beach, Missouri, which was constructed in 2016. Binder testing and mix performance tests were carried out on field cores and laboratory compacted specimens.
Based on the findings of the study, the following conclusions were drawn: (1) Missouri’s practices for the responsible and effective use of recycled materials is sound and continues to improve over time. Recent mix designs demonstrate more appropriate balancing between recycled material levels and virgin binder selection, resulting in better performance tests results when compared to older recycled mix designs. (2) Opportunities exist for further improving recycled mix design methods and recycling optimization in Missouri, including (a) moving to higher asphalt binder replacement (ABR) levels, by implementing mixture performance tests (balanced mix design); (b) increasing the use of recycled ground tire rubber (GTR) in Missouri mixes, by using balanced mix design to certify mixes using new, more economical GTR recycling methods, and; (c) researching the use of recycled materials in stone-mastic asphalt (SMA) designs.
It is recommended to further evaluate and fine-tune mix performance tests for use in balanced mix design, which is particularly important for modern, heterogeneous recycled mixes.
Funding Sources:
Midwest Transportation Center
USDOT/OST-R ($200,000.00)
Missouri Department of
Transportation ($200,000.00)
University of Illinois ($70,000.00)
Total: $470,000.00
Contract Number: DTRT13-G-UTC37
Researchers
Carlos Sun
About the research
The Highway Safety Manual (HSM) is a national manual for analyzing the highway safety of various facilities, including rural roads, urban arterials, freeways, and intersections. The HSM was first published in 2010, and a 2014 supplement addressed freeway interchanges. The HSM incorporated the safety modeling results from several National Cooperative Highway Research Program projects that used data from various states across the nation. The HSM recommended that individual states calibrate the HSM to local conditions on a regular basis. An initial statewide calibration for Missouri was finalized in 2013. The current recalibration effort builds upon the previous calibration and is designed to keep the calibration values up to date with the most current crash data and calibration methodologies. The current effort also involves the development of crash severity distribution functions so that crash frequencies can be estimated according to the severity categories of fatal, severe injury, minor injury, and property damage only. HSM calibration is a labor-intensive effort that requires the collection and use of detailed data such as road geometrics, traffic volumes, traffic signalization, land use, and crash frequency and severity. This report documents the details of the methodology employed for facility site selection, data collection, data processing, calibration, and severity assignment. Sixteen facility types were calibrated. These included rural two-lane segments with the related three-leg and four-leg intersections; rural multilane segments with the related three-leg and four-leg intersections; urban two-, four- and five-lane arterial segments; urban and rural four-lane and urban six-lane freeway segments; urban three- and four-leg signalized intersections; and urban three- and four-leg unsignalized intersections. The calibration results indicated that the HSM predicted Missouri crashes reasonably well, with the exception of a few site types for which it may be desirable for Missouri to develop its own safety performance functions in the future.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($145,977.00)
USDOT/OST-R ($145,743.00)
Total: $291,720.00
Contract Number: DTRT13-G-UTC37
Researchers
Praveen Edara
Carlos Sun
About the research
Effective signage that is easily understood facilitates safe driving through a work zone. While the guidance for work zone signage in the Manual on Uniform Traffic Control Devices (MUTCD) is suitable for many conditions, there may be instances where alternative signage may be more effective at enhancing safety. This project evaluated the use of alternative signage for closure of a middle lane in a freeway work zone on a bridge rehabilitation project on I-170 in St. Louis, Missouri. The alternative signage displays the lane arrangement in a single sign, while the MUTCD recommends using two signs to direct the movements to the left and the right sides of the work area. The evaluation of the alternative signage included stakeholder and driver surveys, operational and safety analyses, and the collection and analysis of field videos to assess driver behavior.
The analysis of field videos showed that drivers may have adapted to the alternative sign because the rate of lane changes decreased between the early and late periods of construction. Stakeholder interviews found that personnel from the Missouri Department of Transportation (MoDOT) and the contractor generally thought that the alternative sign communicated information more clearly but had mixed opinions on whether the use of the sign improved safety. Drivers did not express any concerns regarding the use of the alternative sign through a website that collects feedback on MoDOT work zones. A review of crash data found that crash patterns during the work zone period were similar to the crash patterns before the work zone was in place, and the use of the alternative sign did not appear to be a contributing factor in any work zone crashes. Analysis of Regional Integrated Transportation Information System (RITIS) traffic data found that use of the alternative sign did not have an impact on travel times in the vicinity of the work zone. Overall, the evaluation found that the alternative sign communicates information clearly and does not cause any adverse impacts to work zone safety and operations.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($75,000.00)
USDOT/OST-R ($75,052.00)
Total: $150,052.00
Contact Number: DTRT13-G-UTC37
Researchers
Glenn Washer
About the research
The objective of this project is to develop new nondestructive evaluation (NDE) technology for the condition assessment of post-tensioned bridge components.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($50,593.00)
University of Missouri – Columbia ($9,407.00)
USDOT/OST-R ($60,000.00)
Total: $120,000.00
Contract Number: DTRT13-G-UTC37
Researchers
Glenn Washer
About the research
This research studies a bridge in Kansas City, Missouri that was constructed in 1959 but never opened to traffic to assess its deterioration and compare results from different nondestructive testing methods.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($58,271.00)
University of Missouri – Columbia ($12,988.00)
USDOT/OST-R ($83,009.00)
Total: $154,268.00
Contract Number: DTRT13-G-UTC37
Researchers
Carlos Sun
Praveen Edara
Charles Nemmers
Bimal Balakrishnan
About the research
The J-turn, also known as restricted crossing U-turn (RCUT) or superstreet, is an innovative geometric design that can improve intersection safety. Even though this design has been in use in several states for many years, there is very little research-based guidance for several design parameters.
A driving simulator study was conducted to analyze the parameters of lane configuration, U-turn spacing, and signage. Two lane configurations were examined: 1) acceleration/deceleration configuration where acceleration and deceleration lanes are provided and 2) deceleration only configuration where only deceleration lanes are provided.
Lane configuration was found to be the most important parameter affecting J-turn safety based on speed differentials. The only significant interaction effect among parameters was between lane configuration and U-turn spacing. The acceleration/deceleration configuration performed better than the deceleration only configuration with 66.3 percent fewer safety critical events. Vehicle trajectories and average lane-change locations showed that U-turn spacing impacted significantly the acceleration/deceleration configuration (i.e., average merge locations changed by 96 to 101 percent), but not the deceleration only configuration. No strong preference was demonstrated by the study subjects for either the directional or the diagrammatic signage style.
This project represents the first human factors study of the J-turn focused on developing design guidance. This human factors approach complements other traditional approaches such as crash analysis and micro-simulation.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($99,207.00)
University of Missouri – Columbia ($69,272.00)
USDOT/OST-R ($99,965.00)
Total: $268,444.00
Contract Number: DTRT13-G-UTC37
Researchers
Sarah Orton
About the research
The project will experimentally evaluate the current and improved expansion joint designs under different loading conditions. Full-scale finger plate designs will be built and tested in the laboratory to evaluate their performance and fatigue life.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($297,289.00)
USDOT/OST-R ($73,570.00)
Total: $370,859.00
Contract Number: DTRT13-G-UTC37
Researchers
Praveen Edara
Carlos Sun
Henry Brown
About the research
In support of its Toward Zero Deaths (TZD) initiative, the Missouri Department of Transportation (MoDOT) initiated this research project to develop guidance on treatments that can reduce crashes and fatalities. The first task for this project was to synthesize the literature and state of the practice related to system-wide safety treatments and document the treatments’ effectiveness. In particular, the objective was to examine those treatments that have not already been implemented in Missouri. The safety effectiveness, implementation guidelines, limitations, costs, and concerns of the treatments were documented. The identified safety treatments work in conjunction with the “Necessary Nine” strategies identified in the Missouri Blueprint. Accordingly, the synthesis covered three areas: (1) horizontal curves, (2) intersections, and (3) wrong-way crashes. The reviewed treatments included signing, geometric design and access management, intelligent transportation systems (ITS), pavement markings, and signal control enhancements to improve safety. In the last few years, MoDOT has replaced several high-crash intersections on rural highways in the state with J-turns. Given their safety effectiveness and low cost, J-turns have become a preferred alternative to replace high-crash two-way stop-controlled intersections on high-speed highways. Unfortunately, national guidance on the design of J-turns is very limited. This project addressed this gap in practice by developing guidance on spacing and acceleration lanes. A thorough examination of crashes that occurred at 12 existing J-turn sites in Missouri was conducted. The crash review revealed the proportions of five crash types occurring at J-turn sites: (1) major road sideswipe (31.6%), (2) major road rear-end (28.1%), (3) minor road rear-end (15.8%), (4) loss of control (14%), and (5) merging from U-turn (10.5%). The crash rates for both sideswipe and rear-end crashes decreased with an increase in the spacing from the minor road to the U-turn; J-turns with a spacing of 1,500 ft or greater experienced the lowest crash rates. A calibrated simulation model was used to study various volume scenarios and design variables. For all scenarios, the presence of an acceleration lane resulted in significantly fewer conflicts. Therefore, acceleration lanes are recommended for all J-turn designs, including lower volume sites. Moreover, while a spacing between 1,000 and 2,000 ft was found to be sufficient for low-volume combinations, a spacing of 2,000 ft is recommended for medium- to high-volume conditions.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($80,091.00)
University of Missouri – Columbia ($63,232.00)
USDOT/OST-R ($80,278.00)
Total: $223,601.00
Contract Number: DTRT13-G-UTC37
Researchers
Glenn Washer
About the research
The objective of the research was to determine the frequency and cause of resonant vibrations of vertical truss members on bridge A4497 over the Missouri River in Jefferson City, Missouri. Instrumentation to monitor the vibrations of four vertical members was installed on the bridge and monitored for 42 days. Weather data available from the weather station at the Jefferson City Memorial Airport were used to analyze weather conditions causing resonant vibrations of the four vertical members.
Eleven vibration “events” were found where vertical members vibrated with higher than normal acceleration. The researchers also analyzed historical weather data to determine how frequently the resonance vibrations were occurring. The research team concluded that the frequency of resonant vibration events was likely 0.25 or fewer events per day. The vibrations were caused by average winds from the west-northwest, northwest, or southwest of approximately 17 mph or greater, based on monitoring results.
Recommendations stemming from the research are as follows:
- The effect of the vibration events on the durability of the vertical truss members should be analyzed further to determine if a retrofit is necessary. The data provided through the field monitoring should be used in the analysis.
- Other vertical members of similar lengths should be monitored to determine if they are also affected by resonant vibrations.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($15,000.00)
USDOT/OST-R ($15,000.00)
Total: $30,000.00
Contract Number: DTRT13-G-UTC37
Researchers
Carlos Sun
Praveen Edara
Henry Brown
Charles Nemmers
About the research
The American Association of State Highway Transportation Officials (AASHTO) released a supplement to the Highway Safety Manual (HSM) in 2014 that included models for freeway interchanges composed of segments, speed-change lanes, and terminals. A necessary component when using the HSM is having the appropriate safety-related data. However, a high percentage, approximately 75 percent, of interchange crashes in the Missouri Department of Transportation (MoDOT) Transportation Management System (TMS) are landed on an incorrect location within an interchange. For example, crashes are frequently assigned to the midpoint of the ramp terminal instead of to one of the two ramp terminals. Another example includes crashes that are assigned to the freeway mainline when the crashes are related to the ramps. In order to properly calibrate and use HSM freeway interchange models, the location of crashes needs to be corrected. Crash landing correction involves the visual inspection of crash images compiled by the Missouri State Highway Patrol. A detailed procedure was established along with a reviewer test so that crash correction can be conducted uniformly among multiple reviewers. A total of 10,897 crashes were reviewed and 9,168 underwent detailed review and correction. Among the total crashes reviewed, 1,482 were partial cloverleaf crashes, 5,086 diamond interchange crashes, 780 ramp crashes, and 1,820 speed-change lane crashes. The crash location correction process helped to eliminate the error rate associated with interchange crash locations by 69 percent. Any analyst can correct crash locations by following the procedure detailed in the final report for this project.
Funding Sources:
Midwest Transportation Center
Missouri Department of Transportation ($59,996.00)
University of Missouri – Columbia ($36,278.00)
USDOT/OST-R ($92,698.00)
Total: $188,972.00
Contract Number: DTRT13-G-UTC37