A New Model of Crash Severities Reportable to the MCMIS Crash File

The Motor Carrier Management Information system (MCMIS) Crash file has been developed by the Federal Motor Carrier Safety Administration (FMCSA) to serve as a census file of trucks and buses involved in traffic crashes meeting a specific crash severity threshold. Each state is responsible for identifying cases that meet the MCMIS Crash file criteria and reporting the required data through the SafetyNet system. The present report is an addition to three previous reports describing models to predict the number of crash involvements a state should be reporting. The model has been updated and changed over time as more data becomes available from additional states. In each state, the number of fatal involvements is well-known, so all states will start with a known quantity, the number of fatal truck and bus crash involvements. The new model also incorporates a rural/urban (RU) factor that accounts for the relative proportion of rural to urban truck travel in a state. In the new model, data from 16 states that provide all the information necessary to identify MCMIS-reportable cases were used. A log-linear model is fit to MCMIS data for the states that have information recorded for both fatal and nonfatal crashes. The model is then used to predict the number of nonfatal crashes for a new state in which the number of fatal crashes and the RU factor are known. Ninety percent prediction intervals provide a range of nonfatal crash values to be used for guidance. The new model provides more accurate prediction than previous models and is expected to be updated as data from additional states become availableFederal Motor Carrier Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/89595/1/102787.pd

Tracking the use of onboard safety technologies across the truck fleet

Special ReportThe Transportation Safety Analysis and the Automotive Analysis Divisons at the University of Michigan Transportation Research Institute (UMTRI) initiated the Onboard Safety Technologies project in 2007, supported by FMCSA, to collect detailed information about the penetration of onboard safety technologies in the trucking fleet and future use of these technologies. The five technologies examined included: lane departure warning (LDWS), electronic stability control (ESC), forward and side collision warning (FCWS/SCWS), and vehicle tracking systems (TRACKING). Previous work in estimating the penetration of onboard safety technologies never approached the question of technology penetration by sampling the popluation of trucking companies. This project uses that approach through the use of a random sample survey of the entire fleet of trucking companies to measure current penetration, future use, and the advantages available to companies employing these technologies. The source for the sample was the 2007 Motor Carrier Management Information System (MCMIS) file. Interviews were also conducted with companies with high penetration of the technologies as well as system suppliers of the technologies, in order to gather more detailed information about usage and future technology direction. The results of the survey show the expected low levels of usage of LDWS, FCWS, and SCWS, slightly higher levels of usage of ESC, and much higher usage of TRACKING. Analysis shows higher usage related to larger company size. Company usage of these technologies is expected to double over the next five years. The main factors noted by participants for using the technologies that vary little among the technologies include: proven safety benefits of the technologies, positive feedback by drivers, driver improvement, improved safety culture, reduced cost of accidents, and insurance benefits. The interviews yielded important views about the cost advantages of usage, the difficulty of justifying the purchase of the technologies, alternatives to safety technologies, and the future of technology integration.Federal Motor Carrier Safety Administration, Washington, D.Chttp://deepblue.lib.umich.edu/bitstream/2027.42/91262/1/102868.pd

Inductive Reasoning Games as Influenza Vaccination Models: Mean Field Analysis

We define and analyze an inductive reasoning game of voluntary yearly vaccination in order to establish whether or not a population of individuals acting in their own self-interest would be able to prevent influenza epidemics. We find that epidemics are rarely prevented. We also find that severe epidemics may occur without the introduction of pandemic strains. We further address the situation where market incentives are introduced to help ameliorating epidemics. Surprisingly, we find that vaccinating families exacerbates epidemics. However, a public health program requesting prepayment of vaccinations may significantly ameliorate influenza epidemics.Comment: 20 pages, 7 figure

The Effect of Expanded Antiretroviral Treatment Strategies on the HIV Epidemic among Men Who Have Sex with Men in San Francisco

Modeling of expanding antiretroviral treatment to all HIV infected adults already in care in San Francisco predicts reductions in new HIV infections at 5 years of 59% among men who have sex with men (MSM). Addition of annual HIV testing for MSM to universal treatment decreases new infections by 76%

The safety profile of work-related trucks

"Special report"This report is an investigation into the safety profile of work-related trucks which includes dump, garbage/refuse, tow/wrecker, cement mixer, utility, and many other single unit vocational trucks. Statistics are presented comparing work trucks to tractor semitrailers, straight truck vans, and passenger cars. Five years (1997-2000, 2002) of fatal crash counts are taken from the Trucks Involved in Fatal Accidents database. Fatal crash counts in 2002 for passenger cars are derived from the Fatality Analysis Reporting System data file. Vehicle miles traveled (VMT) data for trucks are taken from the 2002 Vehicle Inventory and Use Survey, while VMT data for passenger cars are derived from reports published by the Federal Highway Administration. Crash involvement rates per 100 million VMT are calculated and compared among different vehicle types. In addition, fatal crash statistics are presented comparing work trucks, straight truck vans, tractor semitrailers, and passenger cars with respect to road and environment characteristics, vehicle characteristics, and driver characteristics. Based on VIUS VMT, the average annual crash involvement rate for all trucks (class 3 and above) was 3.54. Dump trucks had the highest crash involvement rate (5.96). The rate for garbage/refuse trucks was 5.12, while the rate for tractor semitrailers was 3.63. Straight truck vans had one of the lowest rates (2.09). While fatal crash involvement rates for some of the work trucks appear to be high, aggregated rates do not take into account the kinds of roads that work trucks typically traveled on. Dump trucks accumulated 80% of travel on local trips (50 miles or less), while semitrailers accumulated only 15.8% of travel on local trips. After stratification by trip type, it is shown that rates for many work trucks are comparable to, and in some cases lower than, the rate for semitrailers. On trips greater than 50 miles the rates for dump trucks and garbage/refuse trucks were 2.90 and 1.90, respectively, while the rate for semitrailers was 3.29National Truck Equipment Association, Washington, D.C.http://deepblue.lib.umich.edu/bitstream/2027.42/13897/2/99204.pd

A data model of the Climate and Forecast metadata conventions (CF-1.6) with a software implementation (cf-python v2.1)

The CF (Climate and Forecast) metadata conventions are designed to promote the creation, processing, and sharing of climate and forecasting data using Network Common Data Form (netCDF) files and libraries. The CF conventions provide a description of the physical meaning of data and of their spatial and temporal properties, but they depend on the netCDF file encoding which can currently only be fully understood and interpreted by someone familiar with the rules and relationships specified in the conventions documentation. To aid in development of CF-compliant software and to capture with a minimal set of elements all of the information contained in the CF conventions, we propose a formal data model for CF which is independent of netCDF and describes all possible CF-compliant data. Because such data will often be analysed and visualised using software based on other data models, we compare our CF data model with the ISO 19123 coverage model, the Open Geospatial Consortium CF netCDF standard, and the Unidata Common Data Model. To demonstrate that this CF data model can in fact be implemented, we present cf-python, a Python software library that conforms to the model and can manipulate any CF-compliant dataset

Truck mechanical condition and crashes in the large truck crash causation study

Special reportThis study examines the relationship of heavy truck mechanical condition and crash risk. The LTCCS presents an opportunity to examine in more detail than previously possible the relationship of vehicle condition to crash risk. The report includes a review of existing literature, a full analysis of the results of the post-crash truck inspections, and a series of logistic regression models to test the association of vehicle condition and crash role. Two specific hypotheses are tested: The first hypothesis is that trucks with defects and out of service conditions are statistically more likely to be in the role of precipitating a crash than trucks with no defects or out of service conditions. The second hypothesis is that defects in specific systems, such as the brake system, are associated with crash roles in which those systems are primary in crash avoidance, and that there is a physical mechanism that links the vehicle defect with the crash role. Post crash inspections showed that the condition of the trucks in the LTCCS is poor. Almost 55 percent of vehicles had one or more mechanical violations. Almost 30 percent had at least one out of service condition. Among mechanical systems, violations in the brake (36 percent of all) and lighting system (19 percent) were the most frequent. A brake OOS condition increased the odds of the truck assigned the critical reason (identifying the precipitating vehicle) by 1.8 times. Both HOS violations and log OOS increased by a larger amount—2.0 and 2.2 times respectively. In rear-end and crossing paths crashes, brake violations, especially related to adjustment, increased the odds of the truck being the striking vehicle by 1.8 times.Federal Motor Carrier Safety Administration, Washington, D.C.http://deepblue.lib.umich.edu/bitstream/2027.42/64999/1/102509.pd

Protocols for Dual Tracer PET/SPECT Preclinical Imaging

BACKGROUND: Multi-tracer PET/SPECT imaging enables different modality tracers to be present simultaneously, allowing multiple physiological processes to be imaged in the same subject, within a short time-frame. Fluorine-18 and technetium-99m, two commonly used PET and SPECT radionuclides, respectively, possess different emission profiles, offering the potential for imaging one in the presence of the other. However, the impact of the presence of each radionuclide on scanning the other could be significant and lead to confounding results. Here we use combinations of (18)F and (99m)Tc to explore the challenges posed by dual tracer PET/SPECT imaging, and investigate potential practical ways to overcome them. METHODS: Mixed-radionuclide (18)F/(99m)Tc phantom PET and SPECT imaging experiments were carried out to determine the crossover effects of each radionuclide on the scans using Mediso nanoScan PET/CT and SPECT/CT small animal scanners. RESULTS: PET scan image quality and quantification were adversely affected by (99m)Tc activities higher than 100 MBq due to a high singles rate increasing dead-time of the detectors. Below 100 MBq (99m)Tc, PET scanner quantification accuracy was preserved. SPECT scan image quality and quantification were adversely affected by the presence of (18)F due to Compton scattering of 511 keV photons leading to over-estimation of (99m)Tc activity and increased noise. However, (99m)Tc:(18)F activity ratios of > 70:1 were found to mitigate this effect completely on the SPECT. A method for correcting for Compton scatter was also explored. CONCLUSION: Suitable combinations of injection sequence and imaging sequence can be devised to meet specific experimental multi-tracer imaging needs, with only minor or insignificant effects of each radionuclide on the scan of the other

Evaluation of the CSA 2010 operational model test

In accordance with its primary mission to reduce crashes, injuries, and fatalities involving large trucks and buses, the Federal Motor Carrier Safety Administration (FMCSA) initiated the Comprehensive Safety Analysis 2010 (CSA 2010) Operational Model Test. The program focused on initiating contact with more carriers and drivers, development of a new measurement system to replace Motor Carrier Safety Status Measurement System (SafeStat), application of a wider range of progressive interventions to correct high-risk behavior, and more efficient use of Agency resources. The test ran for 29 months from February 2008 through June 2010. This report is an evaluation of the CSA 2010 Operational Model Test. The evaluation focuses on key components of the model. In particular, measurement system thresholds exceeded in type and frequency, interventions received in type and frequency, and the number and percentage of carriers touched under the new model are calculated and reported. Intervention cycles and patterns are explored and effectiveness of interventions is determined by comparing test carriers that received CSA 2010 interventions to control carriers that did not. Costs to the agency of performing interventions are investigated and compared to the current process of conducting compliance reviews (CRs). The new Safety Measurement System (SMS) that is used to rank a carrier’s safety performance in the seven Behavior Analysis and Safety Improvement Categories (BASICs) is evaluated by assessing associations between percentile scores and crash rates. Comparisons with the current model under SafeStat are reported and quality of the Motor Carrier Management Information System (MCMIS) data files is discussed. Finally, results from a survey completed by field staff participating in the Operational Model Test is presented to determine which aspects of CSA 2010 worked well and which did not.U.S. DOT Office of Analysis, Research, and Technologyhttp://deepblue.lib.umich.edu/bitstream/2027.42/86185/1/102763.pd