Civil Engineering Reference
In-Depth Information
Fig. 7.18 Time-space pattern.
Source
Reference [
5
]
The key considerations from both capacity and congestion perspectives include
(a) the traf
c signal cycle, (b) the number of phases, (c) the amount of green time on
each phase, and (d) the number of lanes and the traf
c volume on each approach.
Detailed procedures for estimating intersection capacities, stopped delays at intersec-
tions, and
are set forth in the 2010 Highway Capacity Manual [
6
].
Figures
7.19
and
7.20
show the effects of volume-to-capacity ratios and traf
“
levels of service
”
c
signal spacing on arterial speed. The free-flow speed decreases as the number of
signals per mile increases. And the rate of speed drop diminishes after signal
density exceeds 5 signals per mile.
Fig. 7.19 Suggested speed
estimation curves as a
function of signal spacing and
V/C Ratio
—
Class I arterials.
Source
Reference [
7
],
Fig.
7.10
