The present invention relates to systems for warning of impending vehicle collisions.

Emergency vehicles such as fire trucks, police cars, ambulances and rescue vehicles, speeding toward a destination, pose a potential collision hazard to other motorists, particularly in metropolitan areas.

Although emergency vehicles typically have sirens and lights to warn of their approach, these warning devices are of limited effectiveness.

The direction from which a siren is approaching may be difficult for motorists to judge due to sound reflections from buildings.

Flashing lights are only visible to motorists within a clear line of sight from the emergency vehicle, e.g., to motorists on the same straight section of street as the emergency vehicle.

For example, a motorist on a street around the corner from the emergency vehicle may not be able to determine the location of the emergency vehicle or judge whether he is in danger of colliding with the emergency vehicle until it is too late; by the time the driver sees the emergency vehicle he may not have time to react.

Furthermore, even if a motorist is able to judge the direction from which an emergency vehicle is approaching, the motorist may have difficulty judging the speed at which it is approaching.

Even in rural areas, approaching emergency vehicles pose a danger to motorists because the sirens and lights of the emergency vehicles divert motorists'attention from driving.

It would be desirable to provide an effective system for warning drivers of approaching emergency vehicles.

The present invention addresses these problems and deficiencies and others in the manner described below.

The present invention relates to a method and system for alerting a driver of a first vehicle of an approaching second vehicle that includes a navigation information system in each vehicle, a transmitter in the second vehicle, a receiver in the first vehicle, a processing system, and a warning system in the first vehicle.

One of the vehicles may be a private or commercial vehicle such as an automobile, while the other may be an emergency vehicle such as an ambulance, firefighting vehicle, police vehicle or a rescue vehicle.

Each navigation information system provides data that describe the geographic position and speed of the vehicle.

The navigation information systems may, for example, use the global positioning satellite (GPS) system to obtain such data, or may obtain some or all such data from sensors and systems integral to the vehicle, such as a speedometer.

The transmitter transmits at least a portion of the navigation information relating to the second vehicle.

The receiver receives movement information that may consist of the transmitted navigation information or include at least a portion of it.

Alternatively, the movement information that the receiver receives may consist of information transmitted by a base station at a geographically fixed location or at least include a portion of it.

The processor, which may be located in the first vehicle or, alternatively, at any other suitable location, such as a base station or another vehicle, determines the position and direction of travel of the second vehicle relative to the first vehicle in response to the movement information and the navigation information relating to the first vehicle.

The movement information may consist of any suitable information associated with relative movement of first and second vehicles, including a straightforward warning signal, but preferably includes the navigation information relating to the second vehicle.

The warning system in the first vehicle provides a suitable indication to alert the driver if the processing system determines that the first and second vehicles are within a predetermined proximity of one another, though in some embodiments of the invention the warning system may take other parameters into account, such as the course on which the vehicles are headed and whether they are therefore likely to collide.

In some embodiments of the invention, the warning system may provide additional information, such as indications of the direction and speed of the vehicles relative to one another.

The indicator devices that provide such indications may include any suitable audible or visual displays, including straightforward indicator lights, buzzers and the like, as well as more sophisticated map-like graphical displays.

It is-also contemplated that graphical information can be provided to one or both drivers that indicates a safer alternative route, i.e., a route that is not likely to intersect with the route of the other vehicle.

The present invention provides rapid identification of the relative location and speed between two vehicles, such as a private (or commercial) vehicle and an emergency vehicle.

The invention can alert the driver of the private vehicle of the presence of an emergency vehicle, even if the vehicles are still far apart but are headed on courses that are likely to intersect one another.

A novel visual display can be included to show the location of both vehicles.

The invention can thus enhance safety for the drivers of both private and commercial vehicles.

The foregoing, together with other features and advantages of the present invention, will become more apparent when referring to the following specification, claims, and accompanying drawings.

Simplified navigation directions are provided when a navigation compact disk is not available in a shared compact disk reader.