Civil Engineering Reference
In-Depth Information
Fig. 7.12 Offset freeway
interchange
to prevent cross
weaving maneuvers and lane imbalance, these locations are
the source of capacity bottlenecks that cause substantial peak period delays.
—
Complex Weaving Freeway Sections: Freeway weaving areas, where traf
c
must merge across several lanes to leave the freeway, can become congestion
bottlenecks. This is especially so where the weaving section is too short
—
requiring traf
c to slow down to
find acceptable gaps to maneuver between
lanes. These weaving con
icts are most problematic where there are left-side
entry and right side exit, or right side entry and left side exit ramps, and there are
several freeway lanes to cross (Fig.
7.13
).
fl
Short Freeway On-Ramps
:
Short freeway on ramps, especially with inade-
quate (short) acceleration lanes cause merging traf
c to enter gaps by forcing
through traf
c to slow down. An example is given in Fig.
7.14
.
Short Freeway Off-Ramps: Exit ramps with short deceleration lanes require
exiting traf
c to slow down while still in the through freeway lanes. These
Fig. 7.13 Right side entry ramps and left side exit ramp causing complex weaving maneuvers
