TY  - JOUR
PY  - 1975//
TI  - Detecting freeway incidents under low-volume conditions
JO  - Transportation research record
A1  - Messer, Carroll J.
A1  - Ritch, Gene P.
A1  - Weaver, Graeme D.
A1  - Dudek, Conrad L.
SP  - 34
EP  - 47
VL  - 533
IS  - 
N2  - Two computer algorithms for automatic, freeway-incident detection under low-volume conditions were developed. The first approach uses a time-scan process. The second approach, considered to be superior to the first, operates on an event-scan principle. Computer simulations produced a family of curves that are useful in determining sensor- spacing requirements for an operational system using the event-scan algorithm. The results indicate that, when detector spacings of 1,000 ft (304.8 m) are used, all incidents on a 3-lane freeway section can be detected within 3 min for volumes up to 500 vehicles per hour. When volumes approach 1,000 vehicles per hour, 85 percent of the incidents can be detected within 3 min. Faster detection capabilities at the higher volumes would require closer detector spacings. Incident-detection operational considerations, particularly the manner in which software can be developed to recognize and compensate for vehicle-count errors produced by semitrailers and lane-change maneuvers, also are discussed.<p />
LA  - en
SN  - 0361-1981
UR  - http://dx.doi.org/
ID  - ref1
ER  -