ITS Berkeley

This paper extends the well known Held-Karp's lower bound available for a single Travelling Salesman Problem to the multiple depot case. The LP-relaxation of a symmetric multiple vehicle, multiple depot problem is shown to be lower bounded by an infinite family of bounds. Each lower bound can be computed in a tractable way using a matroid intersection algorithm. When the costs of travelling between any two locations satisfy triangle inequality, it is shown that there exists a 2-approximation algorithm for solving the multiple depot, multiple TSP. These results are useful in solving the...

California boasts nine national parks that are home to a plethora of recreational, cultural, and professional opportunities. It is no surprise that national parks draw in millions of recreational and non-recreational trips from across the country and internationally, however how visitors choose to arrive at these federal lands is a major consideration for land management, policy, and infrastructure decisions. According to the National Park Service’s Visitor Use Statistics, an overwhelming majority of visitors arrive by automobile. Alternative transportation options to national parks in...

The transportation landscape is in transition. Rising congestion, failing infrastructure, changing behaviors, adapting to a more inclusive definition of mobility, the desire for cleaner and more efficient engines, and grappling with the role of autonomous vehicles and drones, to name just some of the factors, demands that we take a fresh approach to designing for mobility. Yet the rapid pace of technology development is creating emerging trends that are driving change faster than our ability to model, design, and manage them. This could potentially result in undesirable economic,...

The arrival times of vehicles traveling southbound along a two-lane, bi-directional highway were recorded at eight neighboring locations upstream of a bottleneck caused by an oversaturated traffic signal. Cumulative curves constructed from these observations describe completely and in great detail the evolution of the resulting long queues. These queues formed directly upstream of the signal when the signal's service rate fell below the southbound arrival rates, and never formed away from the bottleneck. The predictability of bottlenecks like the one studied here can be exploited to manage...