The Dayton ITS Demonstration Project: Simulating Existing Conditions

The Miami Valley Regional Planning Commission is incorporating an Advanced Traveler Information System to alleviate real-time traffic problems associated with special events at the Ervin J. Nutter Center of the Wright State University. This study of the existing conditions is part of the evaluation plan and addresses two tasks: 1) documentation of the existing conditions; and 2) definition of measures of effectiveness. The existing conditions were depicted with the use of a computer simulation software package, Traffic Software Integrated System and separate scenarios were modeled for three existing conditions: ingress and egress for a special event and a major shopping day. For each of the modeled scenarios, several runs were conducted to accurately picture the traffic environment and avoid possible outliers due to the stochastic nature of the simulation program. Model calibration and validation was also used by conducting travel time studies. Several measures of effectiveness were chosen including travel times, delays, and system speeds. Finally, specific routes were studied for each of the scenarios and problem areas were identified

Review of Highway Cost Allocation Methodologies

The objectives of the current cost allocation study, the fifth in a series begun in 1982, include the following: 1) to evaluate current cost allocation methodologies and identify possible changes to Kentucky practices; and 2) to determine the 1991 fiscal year levels of cost responsibility and revenue contribution for each of several classes of highway users. Additional objectives include an evaluation of the equity of tax proposals advanced by the Kentucky Motor Transport Association, a preliminary determination of the revenue and cost implications of the Extended-Weight Coal Haul System, and an evaluation of the efficiency with which certain highway user taxes have been collected. As was the case in other recent cost-allocation studies, incremental cost assignment has been replaced with various highway use measures including vehicle-miles of travel, axle-miles, passenger-car-equivalent miles, and equivalent-single-axle-load miles. Results from the analysis indicate that cost responsibility was borne most heavily by passenger cars and motorcycles (44.2 percent). Other cost responsibilities were 24.6 percent for heavy trucks; 20.4 percent for pickups and vans; and 10.8 for all other groups. When compared to revenue for each vehicle class; cars, pickups and vans, and heavy trucks exceeded their cost responsibility, while medium trucks fell significantly short. From a limited examination of the Extended-Weight Coal Haul System, it was found that an estimated $2 million are lost annually from the Road Fund because fewer trucks are registered. Heavier weights of coal-decal trucks add approximately$9 million annually to pavement overlay costs. Related to tax collection, it was found that the weight-distance tax was collected at an efficiency of about 70 percent and other user-reported fuel taxes in the range of 75 to 77 percent

Evaluation of Advanced Surveying Technology for Accident Investigation

The objective of this study was to evaluate the use of advanced surveying technology tor the investigation of traffic accidents. The analysis shows that the investigation of traffic accidents using total station (survey) equipment provides a substantial improvement over the traditional coordinate procedure. The number of measurements obtained at an accident scene increased (by a factor of about two) when the total station equipment was used while the time required to collect the measurements decreased by about 33 percent with the man hours decreased by about one-halt. The increase in the number of measurements results in a more accurate and detailed investigation and accident diagram than typically obtained with the coordinate procedure. The use of computer plotting in the total station procedure results in a significant time savings when a detailed accident diagram is needed. It is recommended that the use of total station equipment be continued and expanded

Potential Effect of Cable Median Barriers on Commercial Vehicle Crossover Crashes

In 2016, commercial motor vehicles (CMVs) were involved in 4,079 fatal crashes in the U.S., representing 11.8 percent of all fatal crashes. State of Kentucky crash data for 2015-2016 show that per capita crash rates and increases in crash-related fatalities exceeded the national average. Crossover crashes occur when a vehicle leaves its intended path and veers into the path of oncoming traffic, typically resulting in head-on or sideswipe opposite direction crashes. Cable median barriers are a countermeasure which can potentially be used to mitigate crossover crashes. This research investigated the potential effectiveness of cable median barriers on CMV crashes. Analysis relied on an expert panel approach that evaluated the potential effects of cable barriers on altering the crash severity for fatal and incapacitating injuries (K and A in the KABCO severity index) and developed safety performance functions (SPFs) that resulted in crash prediction models that can be used to develop crash modification factors (CMFs) for estimating how the presence of cable median barriers can potentially affect crash occurrence and severity. The expert panel analysis concluded that safety gains are possible by installing cable median barriers and that their effectiveness is greater for fatalities. The average score of over 2 from the panel (on a scale from 0-5) indicates a moderate effect on crash outcomes. SPFs developed also supported the overall expert panel assessment. Analysis found that CMV crash outcomes benefit from installing cable median barriers, although only interstate routes were examined. The results indicate that CMV crashes will indeed be mitigated by installing cable median barriers. Both analyses supported this finding, and the overall conclusion is one of a positive impact. Benefits may be greater on divided roadways, since installations on two-lane roads may be more problematic due to space limitations. Additional research is recommended to evaluate this finding in light of which vehicle is the errant vehicle, since there could be significant implications for assessing the effectiveness of the cable median barrier if the CMV is the crossing-over vehicle

Towards Understanding the Roaming Mechanism in H + MgH → Mg + HH Reaction

The roaming mechanism in the reaction H + MgH →Mg + HH is investigated by classical and quantum dynamics employing an accurate ab initio three-dimensional ground electronic state potential energy surface. The reaction dynamics are explored by running trajectories initialized on a four-dimensional dividing surface anchored on three-dimensional normally hyperbolic invariant manifold associated with a family of unstable orbiting periodic orbits in the entrance channel of the reaction (H + MgH). By locating periodic orbits localized in the HMgH well or involving H orbiting around the MgH diatom, and following their continuation with the total energy, regions in phase space where reactive or nonreactive trajectories may be trapped are found. In this way roaming reaction pathways are deduced in phase space. Patterns similar to periodic orbits projected into configuration space are found for the quantum bound and resonance eigenstates. Roaming is attributed to the capture of the trajectories in the neighborhood of certain periodic orbits. The complex forming trajectories in the HMgH well can either return to the radical channel or “roam” to the MgHH minimum from where the molecule may react