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3 CHAPTER ONE INTRODUCTION BACKGROUND extent of these differences and their impact on the goal of more uniform permitting is not well understood. Identifying Trucking is an important transportation mode for the economy and documenting the different bridge evaluation practices of this country. Trucking is regulated not only by federal rules used for OS/OW vehicle permits are considered to be an but also by state and sometimes local legislation and policies. important step toward more uniform permitting. In particular, trucks that exceed the legal limits for dimension and weight are required to have a permit to operate, which is This synthesis study focuses on overweight vehicle per- referred to as an oversize/overweight (OS/OW) permit. The mit review that requires bridge evaluation. However, other criteria used in the permitting process are not uniform among potentially relevant subjects are also addressed to have a different jurisdictions. Nonuniformity has been a concern for complete understanding of the subject. the trucking industry, with respect to different lengths of time needed to have a permit review completed, different results of permit application for the same load, the need to change the OBJECTIVE vehicle configuration to transport the same goods through dif- ferent states, etc. Note that some of the factors contributing to The objective of this synthesis study is to gather information on nonuniformity are difficult to control. For example, many state bridge rating systems, bridge evaluation practices, and states have thresholds for the definition of "superload" that re- permit policies, as they relate to overweight and oversize vehi- quire evaluation of all the bridges on the planned route. These cles. The information is intended to help in the understanding thresholds are often defined by state legislation or policies es- of the reasons for nonuniformity in permit practices, and thus tablished at different times in the past. Making them uniform to encourage the development of possible solutions. can be difficult if not impossible. APPROACH In permit review, particularly for overweight trucks, bridge capacity is important. As opposed to pavements for This study was approached using the following steps. which truck wheel loads are critical factors, bridges are required to carry the entire truck load, depending on the re- A survey was conducted of transportation agencies at lation between the vehicle and the bridge lengths. When a the state level in the United States and their counterparts bridge on the route is determined to be unable to carry the in Canada to understand the operations of permit review load, the permit cannot be issued. Therefore, bridge capacity and issuance and related bridge evaluation and load rat- sometimes becomes the weakest link in issuing a permit. ing. The questionnaire was initially sent to four states and then further revised to address the issues and con- Some state permitting offices have worked with industry cerns thereby generated. The final questionnaire was toward a goal of increased uniformity in permitting over- distributed to state-level transportation agencies in the weight and oversize trucks within and between states. His- United States and several agencies in Canada and is torically, most of that effort has been focused on state laws given in Appendix A. A total of 44 agencies from and regulations governing motor carriers. Relatively little United States and 10 from Canada returned the ques- attention has been directed toward the contribution of state tionnaire and their responses are summarized and dis- bridge evaluation practices and procedures toward achieving cussed in this report. this goal. This issue is a focus of the present study. A literature search was performed that included the use of the World Wide Web to understand previous relevant Bridge evaluation for permit review is very much related work with regard to bridge evaluation for truck permit to bridge load rating practice, and both may vary between issuance. The identified research reports, papers, and and within states. Choice, interpretation, and limitation of the other publications were reviewed and are summarized specifications, software tools, treatment of nonstandard con- and discussed in this report. figurations (such as axle gages and multiple-lane configura- Telephone interviews were conducted with targeted or- tions), and allowances for in-place dead loads are examples ganizations and individuals to supplement the informa- of those areas where variation in practice often exists. The tion acquired through the survey and literature review.