Cycling into the Future: Implementation of Enhanced Bikeways Along San Fernando Street in Downtown San Jose

In 2012, the City of San Jose acquired funding from the Transportation for Livable Communities Grant Program and began installing “green striped” enhanced bicycle lanes on a 1.5 mile stretch San Fernando Street between Diridon Station and 10th Street connecting San Jose’s Downtown Train Station to San Jose State University. According to city documents, these enhanced bikeways are intended to “enhance the visibility and safety of this route as a primary bikeway.” An important element of the project was the installation of LED streetlights to improve nighttime visibility. This specific project undertaken by the city falls under the umbrella of its Bike Plan 2020, intended to transform San Jose into “a city where bicycling is safe, convenient, and commonplace.” One of the Bike Plan’s primary goals is to reduce bicycle collision rates by 50% before the year 2020. The San Fernando Street Improvement Project and others like it will be validated by “reach[ing] a Gold-level Bicycle Friendly Community status by 2020.” The purpose of this research is to determine whether this project has successfully reduced rates of injuries and fatalities

A bifurcation and symmetry discussion of the Sommerfeld effect

The Arnold Sommerfeld effect is an intriguing resonance capture and release series of events originally demonstrated in 1902. A single event is studied using a two degree of freedom mathematical model of a motor with imbalance mounted to laterally restricted spring connected cart. For a certain power supplied, in general the motor rotates at a speed consistent with a motor on a rigid base. However at speeds close to the natural frequency of the cart, it seemingly takes on extra oscillations where for a single rotation it both speeds up and then slows down. Therefore in a standard experimental demonstration of the effect, as the supplied torque force is increased or decreased, this may give the illusion that the stable operation of the motor is losing and gaining stability. This is not strictly the case, instead small oscillations always present in the system solution are amplified near the resonant frequency. The imbalance in the motor causes a single resonance curve to fold back on itself forming two fold bifurcations which leads to hysteresis and an asymmetry between increasing and decreasing the motor speed. Although as outlined the basic mechanism is due the interplay between two stable and one unstable limit cycles, a more complicated bifurcation scenario is observed for higher imbalances in the motor. The presence of a Z2 phase space symmetry tempers the dynamics and bifurcation picture.Comment: 14 pages, 8 figure