Gf. Newell, A SIMPLIFIED THEORY OF KINEMATIC WAVES IN HIGHWAY TRAFFIC .2. QUEUINGAT FREEWAY BOTTLENECKS, Transportation research. Part B: methodological, 27(4), 1993, pp. 289-303
Citations number
1
Categorie Soggetti
Transportation,"Operatione Research & Management Science","Engineering, Civil
For a freeway having various entrance and exit ramps, the methods desc
ribed in Part I are used to relate the cumulative flow curve at any ju
nction to the net cumulative entrance flow at this junction, and the c
umulative flow curves for the freeway at the next upstream junction an
d/or the next downstream junction. If the type of flow-density relatio
ns typical of freeway traffic are idealized by a triangular shaped cur
ve with only two wave speeds, one for free-flowing traffic (positive)
and the other for congested traffic (negative), then the relationship
is easy to evaluate. The cumulative flow curve at the junction is simp
ly the lower envelope of a translation of the cumulative curve from up
stream and a different translation of the cumulative curve from downst
ream. This relationship is the basic building block for a freeway flow
prediction model described in Part III.