creator Dao, Hoang advisor Li, Zongzhi Nowadays, State transportation agencies have developed management systems as analytical tools to improve roadway safety. Management systems dealing with traffic safety hardware including traffic signs, signals, lighting, pavement markings, guardrails, barriers, and crash cushions have been identified as an important and non-separable part of safety management. As statistics shown, approximately 42,000 deaths on American roads due to vehicle crashes with one of the main causes being in lack of adequately performed safety hardware. It is easily realized that along the time the performance of traffic safety hardware decreases. State transportation agencies have spent millions of dollars on maintenance and replacement of safety hardware in each year. However, most of the agencies have not developed robust methodologies to assess impacts of traffic safety hardware on safety performance and optimize safety hardware investments. This study began with a literature review of safety performance functions and useful service lives of different types of safety hardware. Based on findings of the literature review and case studies conducted nationwide, this research proposes a new risk-based methodology for computing the safety index that assesses impacts of safety hardware conditions on vehicle crashes. The methodology is applied to a computational study by using 5- year data from 2002 to 2006 on 193 highway segments in Ozaukee County, Wisconsin. The results are compared with Empirical Bayesian adjusted crash estimates via statistical tests in order to validate the proposed methodology. Finally, it discusses future directions for continuing refinements of the proposed methodology. Submitted by Dana Lamparello (dlampare@iit.edu) on 2013-03-04T16:38:56Z No. of bitstreams: 2 Final_Thesis_HoangDao_CAEE_July2012.pdf: 1073245 bytes, checksum: 44ca442a8bfee480aedd31d5dc8c01ea (MD5) Signed Title Page.pdf: 7845 bytes, checksum: fc2ce84e28737692351ccde4a27b7186 (MD5) Made available in DSpace on 2013-03-04T16:38:56Z (GMT). No. of bitstreams: 2 Final_Thesis_HoangDao_CAEE_July2012.pdf: 1073245 bytes, checksum: 44ca442a8bfee480aedd31d5dc8c01ea (MD5) Signed Title Page.pdf: 7845 bytes, checksum: fc2ce84e28737692351ccde4a27b7186 (MD5) Previous issue date: 2012-07 M.S. in Civil Engineering, July 2012 2012-07-23 2012-07 http://hdl.handle.net/10560/2900 en Thesis born digital application/pdf In Copyright http://rightsstatements.org/page/InC/1.0/ Restricted Access CAEE / Civil, Architectural, and Environmental Engineering Illinois Institute of Technology Affiliated department