Abstract: A navigation system for mobile use includes street map data used for creating a dynamic map display tracking movement of the vehicle and includes crime data used to provide an overlay on the dynamic display indicating a risk of crime to the vehicle's occupants from the surrounding area. Crime data may be harvested from police websites and/or generated using statistical correlation techniques from other proxy information. Presented crime data indicate crime risk, type of crime, crime date or time of occurrence, and linkage to environmental conditions such as type of weather, temperature, and moonlight.

Abstract: A navigation system for mobile use includes street map data used for creating a dynamic map display tracking movement of the vehicle and includes crime data used to provide an overlay on the dynamic display indicating a risk of crime to the vehicle's occupants from the surrounding area. Crime data may be harvested from police websites and/or generated using statistical correlation techniques from other proxy information. Presented crime data indicate crime risk, type of crime, crime date or time of occurrence, and linkage to environmental conditions such as type of weather, temperature, and moonlight.

Abstract: A motorcycle two cylinder asymmetric ignition timing system includes an electronic ignition advance circuit. A spark advance control signal is derived from a base signal which in turn has a magnitude that is representative of the time duration between spark ignition signals and thus is representative of engine speed. The spark is not advanced at engine speeds up to 300 RPM, is advanced 9.degree. between 300 RPM and 800 RPM and is advanced 16.degree. above 800 RPM. Intersection between a ramp signal which has a duration that is an inverse function of engine speed and a base signal that has an amplitude which is an inverse function of engine speed determines the time at which the ignition signal is generated. The lower the base signal, the sooner the intersection of the ramp with the base signal and thus the earlier the ignition signal. In this fashion the desired advance is attained.