The US Transit Bus Manufacturing Industry

Manufacturing buses for the US transit market has been a challenging business over the last several decades. It is a small market with volatile demand. Many manufacturers have gone bankrupt, left the market, or been acquired by competitors. Manufacturers of transit buses in the US must comply with a wide range of operational and design regulations. The most salient policy areas include regulating emissions, disabled access, procurement, alternative fuels, the Altoona Test, pooled purchases and piggybacking, spare ratios, workforce training, minimum useful life, Buy America, and research & development (R&D). The purpose of this report is to provide policy makers with an update on the state of the industry, an analysis of how government policies are impacting the industry, and suggestions for policies that can help the industry move forward and thrive to best serve the transit-riding public

Policy Issues in U.S. Transportation Public-Private Partnerships: Lessons from Australia, Research Report 09-15

In this report, the authors examine Australia’s experience with transportation public-private partnerships (PPPs) and the lessons that experience holds for the use of PPPs in the United States. Australia now has decades of experience in PPP use in transportation, and has used the approach to deliver billions of dollars in project value. Although this report explores a range of issues, the authors focus on four policy issues that have been salient in the United States: (1) how the risks inherent in PPP contracts should be distributed across public and private sector partners; (2) when and how to use non-compete (or compensation) clauses in PPP contracts; (3) how concerns about monopoly power are best addressed; and (4) the role and importance of concession length. The study examines those and other questions by surveying the relevant literature on PPP international use. The authors also interviewed 23 Australian PPP experts from the academic, public and private sectors, and distilled lessons from those interviews

Improved Bounds for the Excluded-Minor Approximation of Treedepth

Treedepth, a more restrictive graph width parameter than treewidth and pathwidth, plays a major role in the theory of sparse graph classes. We show that there exists a constant C such that for every integers a,b >= 2 and a graph G, if the treedepth of G is at least Cab log a, then the treewidth of G is at least a or G contains a subcubic (i.e., of maximum degree at most 3) tree of treedepth at least b as a subgraph. As a direct corollary, we obtain that every graph of treedepth Omega(k^3 log k) is either of treewidth at least k, contains a subdivision of full binary tree of depth k, or contains a path of length 2^k. This improves the bound of Omega(k^5 log^2 k) of Kawarabayashi and Rossman [SODA 2018]. We also show an application for approximation algorithms of treedepth: given a graph G of treedepth k and treewidth t, one can in polynomial time compute a treedepth decomposition of G of width O(kt log^{3/2} t). This improves upon a bound of O(kt^2 log t) stemming from a tradeoff between known results. The main technical ingredient in our result is a proof that every tree of treedepth d contains a subcubic subtree of treedepth at least d * log_3 ((1+sqrt{5})/2)