Mechanical & Materials Engineering, Department of


First Advisor

John D. Reid

Date of this Version



Ginger, C.G., Development of Iowa DOT Combination Bridge Separation Barrier with Bicycle Railing, Thesis to University of Nebraska-Lincoln Graduate Studies, July 23, 2018.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanical Engineering and Applied Mechanics, Under the Supervision of Professor John D. Reid. Lincoln, Nebraska : August, 2018.

Copyright (c) 2018 Chaz M. Ginger


The Iowa Department of Transportation typically builds separation barriers between vehicle and pedestrian/bicycle facilities when sidewalks or trails are present on vehicular bridges. Currently, Iowa DOT employs a combination bridge rail that utilizes a concrete parapet that previously had been successfully evaluated to National Cooperative Highway Research Program (NCHRP) Report 350 Test Level 4 (TL-4) criteria for these situations. While the parapet had been successfully evaluated, the combination bridge rail system as a whole had not been evaluated to any crash test standards. Iowa DOT desired that researchers at Midwest Roadside Safety Facility (MwRSF) design and test a combination bridge separation barrier to current Manual for Assessing Safety Hardware (MASH) TL-2 standards to use in place of their current, untested system.

During this effort, previous combination rails, low-height vertical parapets, and zone of intrusion (ZOI) studies were reviewed to provide guidance on system design. A simulation effort was also performed to aid in height selection of the parapet, as well as placement of the attached bicycle rail to reduce the amount of negative vehicle-to-rail interaction with the system. Using the information gathered during the review of previous systems and simulation effort, a full system design was produced. It was then recommended that the proposed system be evaluated to MASH test designation 2-11 in order to assess the system’s performance during a vehicle impact scenario.

Advisor: John D. Reid