Abstract: Controlling a traffic signal phase at one or more intersections. A control system at an intersection is configured to operate in one of a first mode or a second mode. While operating the controller in the first mode, in response to a transit priority signal received by the control system from a vehicle assigned transit priority, a green phase of the traffic signal is extended in favor of the vehicle assigned transit priority. While operating the control system in the second mode, in response to a transit priority signal received by the control system from the vehicle assigned transit priority, a current non-green phase of the traffic signal is preempted to a green phase in favor of the vehicle assigned transit priority.

Abstract: Management of traffic signal preemption control equipment. In one approach, logged preemption data is periodically read from each of a plurality of intersections having respective preemption controllers for preempting traffic signals at the intersections. The logged preemption data at an intersection describes operational states of the preemption controller and each vehicle control unit that submitted a preemption request at the intersection and data describing each individual preemption request. The logged preemption data read from the plurality of intersections are stored in a database. The database is monitored for data indicative of changes in operational status of the traffic signal preemption control equipment. In response to the data indicating a change in operational status, data descriptive of the change are output.

Abstract: Managing traffic signal preemption data accumulated at a plurality of intersections. In one approach a method includes reading the preemption data stored at each of the intersections. The preemption data includes for each preemption request an emitter code, and a date and a time the preemption request was submitted. The preemption data read from the intersections are stored in a database, and each emitter code is associated with a vehicle name in the database. Selected preemption data and associated vehicle names are read from the database in response to user input, and the selected preemption data and associated vehicle names are displayed. The database further stores data identifying the intersection from which the preemption data was read.

Abstract: Managing traffic signal preemption at a plurality of intersections. In one approach a security level code that specifies one of a plurality of security levels for at least one jurisdiction is input. The security level controls which emitter codes are allowed to preempt traffic signals at the intersections in the jurisdiction. A set of emitter codes for the plurality of intersections in the jurisdiction is determined in response to the security level code. The set of emitter codes is downloaded to a plurality of preemption controllers at the plurality of intersections in the jurisdiction. Each preemption controller accepts a preemption request only if the preemption request contains an emitter code indicated by the downloaded set of emitter codes as being allowed to preempt traffic signals at the intersections in the jurisdiction.

Abstract: Controlling a traffic signal phase at one or more intersections. A control system at an intersection is configured to operate in one of a first mode or a second mode. While operating the controller in the first mode, in response to a transit priority signal received by the control system from a vehicle assigned transit priority, a green phase of the traffic signal is extended in favor of the vehicle assigned transit priority. While operating the control system in the second mode, in response to a transit priority signal received by the control system from the vehicle assigned transit priority, a current non-green phase of the traffic signal is preempted to a green phase in favor of the vehicle assigned transit priority.

Abstract: Management of traffic signal preemption control equipment. In one approach, logged preemption data is periodically read from each of a plurality of intersections having respective preemption controllers for preempting traffic signals at the intersections. The logged preemption data at an intersection describes operational states of the preemption controller and each vehicle control unit that submitted a preemption request at the intersection and data describing each individual preemption request. The logged preemption data read from the plurality of intersections are stored in a database. The database is monitored for data indicative of changes in operational status of the traffic signal preemption control equipment. In response to the data indicating a change in operational status, data descriptive of the change are output.

Abstract: Managing traffic signal preemption data accumulated at a plurality of intersections. In one approach a method includes reading the preemption data stored at each of the intersections. The preemption data includes for each preemption request an emitter code, and a date and a time the preemption request was submitted. The preemption data read from the intersections are stored in a database, and each emitter code is associated with a vehicle name in the database. Selected preemption data and associated vehicle names are read from the database in response to user input, and the selected preemption data and associated vehicle names are displayed. The database further stores data identifying the intersection from which the preemption data was read.

Abstract: Managing traffic signal preemption at a plurality of intersections. In one approach a security level code that specifies one of a plurality of security levels for at least one jurisdiction is input. The security level controls which emitter codes are allowed to preempt traffic signals at the intersections in the jurisdiction. A set of emitter codes for the plurality of intersections in the jurisdiction is determined in response to the security level code. The set of emitter codes is downloaded to a plurality of preemption controllers at the plurality of intersections in the jurisdiction. Each preemption controller accepts a preemption request only if the preemption request contains an emitter code indicated by the downloaded set of emitter codes as being allowed to preempt traffic signals at the intersections in the jurisdiction.

Abstract: A multiple-word virtual address flexibly expands the virtual address space of a computer system without requiring the modification of the word size of the computer system. In a memory system having a virtual memory mapped to an absolute memory, the virtual memory is divided up into multiple levels each having a plurality of memory banks. Each memory bank has a plurality of words. The multiple-word virtual address provides a plurality of words for specifying the virtual memory level, memory bank, and offset word within the memory bank, to describe a selected memory location. Special instructions are added to the instruction set architecture to set up a window of program visibility, called a peephole, into a selected area of the expanded virtual memory. Existing programs are compatible with the multiple-word addressing scheme, and can also reference virtual memory through a defined peephole. New programs using multiple-word virtual addresses can still call procedures requiring single word virtual addresses.

Abstract: An Internet checksum for use by TCP/IP is generated in a single macro-instruction called a Block Add Octets instruction. Extraneous overhead of macro-instruction looping and bit masking is eliminated by combining checksum operations into a single macro-instruction using a block add approach. The programmer specifies the address in memory and the number of double-words of message data to be added together within a single instance of the Block Add Octets instruction so that looping and jump/branch instructions are not needed. The Block Add Octets instruction fetches all octets (8-bit data segments) contained in full double words from memory and adds them into the checksum. The method handles partial double words of data, full double words, and odd numbers of double words, whereby a double word consists of four octets. The checksum is calculated using one's complement arithmetic rather than two's complement, thereby increasing the speed of checksum calculation because the "end around carry" is eliminated.