Browsing by Author "Tilahun, Nebiyou"

Now showing 1 - 5 of 5
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    An Agent-Based Model of Origin Destination Estimation (ABODE)
    (Journal of Transport and Land Use, 2013) Tilahun, Nebiyou; Levinson, David
    This paper proposes and tests an agent-based model of worker and job matching. The model takes residential locations of workers and the locations of employers as exogenous and deals specifically with the interactions between firms and workers in creating a job-worker match and the commute outcomes. It is meant to illustrate that by explicitly modeling the search and hiring process, origins and destinations (ODs) can be linked at a disaggregate level. The model is tested on a toy-city as well as using data from the Twin Cities area. The toy-city model illustrates that the model predicts reasonable commute outcomes, with agents selecting the closest work place when wage and skill differentiation is absent in the labor market. The introduction of wage dispersion and skill differentiation in the model increases the the average home to work distances considerably. Using data from Twin Cities area of Minneapolis-St. Paul, aggregate commute and wage outcomes from the model are shown to capture the trends in the observed data. Overall, the results suggest that the behavior rules as implemented lead to reasonable patterns. Future directions are also discussed.
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    Impact of Exempting the Recording of Low Level Speed Violations in Minnesota
    (Center for Transportation Studies, University of Minnesota, 2015-02) Douma, Frank; Tilahun, Nebiyou; Spencer, Peck
    This report covers work done to respond to a request from the Minnesota State Legislature that was included in amendments to Minn. Stat. § 171.12, passed in the 2012 Legislative session. Specifically, the report examines the impacts of Minnesota Statute § 171.12, Subd. 6, better known as the “Dimler Amendment,” which calls for certain low-level violations of certain speed limits to not be entered on the violator’s driving record. The statute called for a report from the Commissioners of Transportation, Public Safety and Health on the impacts of increasing the Dimler qualifying range from 5 mph to 10 mph in 60 mph speed zones on travel reliability, travel efficiency, safety, and privacy. Based on the findings of these analyses, the impacts of the 2012 changes were negligible. More significantly, however, in the course of this project, the researchers came upon findings that led them to question the efficacy of the law itself. The public appears to not be aware of the law’s existence, which may be compounded by the fact that the law lays on top of Minnesota’s already complex speed laws and regulations. Further, the exemptions may be benefiting a small, but significant number of repeat offenders, and complicating regulation of commercial vehicle drivers.
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    Impacts of Minnesota’s Primary Seat Belt Law
    (Center for Excellence in Rural Safety, University of Minnesota, 2012-03) Douma, Frank; Tilahun, Nebiyou
    In the spring of 2009, the Minnesota Legislature changed the state’s seat belt law, making not wearing a seat belt a “primary” offense, where officers can ticket drivers for not wearing a seat belt even if no other traffic law is broken. Using data from the Minnesota Crash Records Database provided by the Department of Public Safety, the study utilized two methods of analysis, first comparing actual crash data from July 2009 – June 2011 to expected data based upon trends from July 2004 - June 2009, and second, comparing the expected post law change injury types estimated from the July 2006 – June 2009 crash data to the actual post primary crash data from July 2009 through June 2011. Results of seat belt use and public opinion surveys were also reviewed. This study estimates that there have been 68 - 92 fewer fatalities from motor vehicle crashes, and 320 - 550 fewer serious injuries since the primary seat belt law went into effect. This improved safety record translates into at least $45 million in avoided hospital charges, including a direct savings of nearly $10 million or more tax dollars that would have paid for expenses charged to government insurers. The primary seat belt law has enjoyed the support of over 70% of all Minnesotans and observed use of seat belts statewide has risen from 86.7% in 2008 to an alltime high of 92.7% in 2011.
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    Social Networks and ICT in Location Choice
    (University of Minnesota Center for Transportation Studies, 2009-08) Tilahun, Nebiyou; Levinson, David
    Humans are social animals. We routinely interact with others learning about one another, about places, where to go and what places to avoid. Our activities are coordinated with others; sometimes because we explicitly seek to physically meet with those we know personally, other times the coordination is systemic because of norms and requirements of when those activities can take place (e.g. shopping when the shops are open etc.). With those personally known, interactions serve to exchange information, form social bonds and to create social support systems. With in the transportation realm, the social dimension comes into play in different ways. Two or more people who want to meet face to face have to select a meeting location and travel to that destination. People can also learn about short-term activity locations, or about residences and workplaces through others and make location decisions based upon them. These two areas of social contacts' influence in the location choice is the topic of this report. The report looks into how job search methods can impact home and work location patterns at the aggregate level. It also investigates the role job search methods and their outcomes play in subsequent relocation and residential location decisions at the individual level. A third element that will be considered is the relationship between home, work and activity locations for social meetings. The roles of social networks are explored in work finding, residential location choice, and choices of meeting locations.
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    Statistical Modeling for Intersection Decision Support
    (2006-02-01) Davis, Gary A.; Tilahun, Nebiyou; Mesa, Paula
    This project was a component of the Intersection Decision Support (IDS) effort conducted at the University of Minnesota. In this project, statistical modeling was applied to crash data from 198 two-way, stop-controlled, intersections on Minnesota rural expressways, in order to: (1) identify intersections that were plausible candidates for future IDS deployment; (2) develop a method for estimating the crash-reduction effect of IDS deployment; (3) develop a method for predicting the crash-reduction potential of IDS deployment, and (4) test the hypothesis that older drivers were over-represented in intersection crashes along US Trunk Highway 52. All these objectives were accomplished using hierarchical model structures similar to that employed in the Interactive Highway Safety Design Model. Five rural expressway intersections were identified as having crash frequencies that were atypically high, and this group included the intersection of US Trunk Highway 52 and Goodhue County highway 9, the site chosen for the prototype IDS deployment. It was then determined that a 3-year count of crashes after deployment would probably be sufficient to detect any crash reduction effect due to the IDS, although a reliable estimate of the magnitude of this effect would require a longer test period. Assuming that the effect of an IDS deployment would be to make the crash frequencies at treated intersections similar to that experienced by typical intersections, it was estimated that deployment of the IDS at the five high-crash intersections would, over a 15-year period, result in a reduction of about 308 crashes. Finally, using an induced-exposure approach, twelve intersections were identified as showing over-representation of older drivers, five of these being on US Trunk Highway 52.