Civil Engineering Reference
In-Depth Information
16.7.2 Advantages of One-Way Operations
The reported advantages of one-way streets include the following:
c and
opposing left turns are eliminated, as is the need for special left-turn phases.
b. Simpli
a. Reduced Con
fl
icts at
Intersections: Con
fl
icts between through traf
c Signal Phasing
: Because the need for special left-turn phases is
eliminated, cycle lengths can be shorter resulting in less
ed Traf
and delays.
c.
Improved Traf
c Signal Progression:
Traffic signal offsets along a street can be
set at the designed speed since only direction of travel is involved. The through
band (or
“
red times
”
“
green wave
”
) for one-way
fl
flow is usually greater than that for two-
way
flow because the green wave for
both
directions of travel is smaller. One-
way traf
fl
es signal coordination within a network.
d.
More Opportunities to Add Signals
: Traf
c also simpli
c signals can be added along a street
without any adverse effect on the
“
through band
”
and progression.
e.
Safer Pedestrian Crossings
: There are more traf
c
“
gaps
”
acceptable to pedes-
trians since only one direction of travel is involved
—
making pedestrian cross-
ings easier and safer.
f.
Safer Intersections:
There are fewer traf
c con
fl
icts and eliminating the possi-
bility of head-on collision improves safety.
g.
More Travel Lanes
: Sometimes, one-way operations permit restriping a roadway
to provide an additional travel lane.
16.7.3 Disadvantages of One-Way Operations
Several disadvantages have been cited for one-way streets. Disadvantages include:
a.
Longer Travel Distances
: Some analysts have found that one-way streets
increase the VMT by up to 30 % [
20
].
b.
Increase in Left Turn and Right Turn Volumes
: The doubling up of left and right
turns can increase pedestrian
icts. In areas of very heavy pedes-
trian volumes, and additional signal phase may be needed.
c.
Possible Confusion to Drivers
: Confusion is greatest when drivers are not
familiar with the one-way system and/or the system design is not easily
understood by drivers.
d.
Longer Crossing Distances for Pedestrians:
Where medians formerly separated
opposing directions of travel, pedestrians have longer distances to walk when
medians are removed for one-way operation.
e.
Reduce Store Front Exposure
: One-way streets can adversely impact store front
businesses that depend on pass-by traf
—
vehicle con
fl
c.
f.
Adverse Effects on Transit Riders
: Transit service works best from a standpoint
of passenger perception and identity when it operates in both directions on the
same street. The adverse effects of one-way streets on transit service are greater
when the one-way streets are far apart.
