Publication Data
Optimal Traversal Planning in Road Networks with Navigational Constraints
Abstract: A frequent query in geospatial planning and decision making
domains (e.g., emergency response, data acquisition, street cleaning), is to ¯nd an
optimal traversal plan (OTP) that traverses an entire area (e.g., a city) by navigating
through all its streets. The optimality is de¯ned in terms of the time it takes to
complete the traversal. This time depends on the number of times each street segment is
traversed as well as the navigation time such as the time spent on changing direction
at each intersection. While the problem roots in the classic problems of graph theory,
real-world geospatial constraints of road network introduce new application-speci¯c
challenges. In this paper, we propose two algorithms to ¯nd OTP of a directed road
network. Our greedy algorithm employs a classic graph traversal algorithm. During the
traversal, it utilizes a set of heuristics at each intersection to minimize the total
travel time. Our near-optimal algorithm, however, reduces an OTP problem to an
Asymmetric Traveling Salesman Problem (ATSP) by extracting the dual graph of the
original network in which each edge is represented by a graph node. Using an
approximate solution for ATSP, our algorithm finds a near optimal answer. Our
experiments using real-world road networks verify that our near-optimal algorithm
outperforms the greedy algorithm in terms of the overall cost of its generated
traversal by a factor of two, while its complexity is tolerable in real-world cases.
