| 摘要 |
A road traffic congestion detection system (30) comprises a detector for detecting the presence or lack of presence of at least one vehicle in a detection zone (36) to produce a presence signal; a detector for detecting, when at least one vehicle is in the detection zone, an instantaneous speed of the vehicle or of one of the vehicles in the detection zone to produce a speed signal; and a processor (10) for producing a congestion signal (20) dependent on the presence signal and the speed signal. The detecting means produces the presence signal as a series of pulses dependent on the time the vehicle was present in the detection zone. The congestion signal is also produced as a series of pulses, the pulse width dependent on whether the speed signal satisfies predetermined criteria. The congestion signal may be compatible with the HIOCC algorithm and trigger alerts in a MIDAS system. The detector may use electromagnetic radiation, such as RADAR, and cover two lanes of the carriageway (14, 22) with means to detect only vehicle travelling in one direction. |
