Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-08-24
FLEXIBLE TRAFFIC
| CONTROL TRIED ON
| RHODE ISLAND AVE.
New System to Be Extended
Throughout City if Re-
suits Are Good.
USE OF AMBER LIGHTS
is TO BE RESTRICTED
Varying Time Cycles Is Expected
to Permit Uninterrupted
Flow Of Cars.

The new flexible system Of traffic
control, recommended last year by the
TRAFFIC Advisory Council, was put into
operation today on Rhode Island ave-
nue. between Twelfth and North Capitol
streets.
If is found to facilitate the flow of
traffc it viii be installed throughout
the downtown area, w. A. Van DaIzer,
director Of vehicles and trafic, an
nounced.
The system is called the complete
progressive traffic signal system and
carries the Endorsement of the fore
most traffic engineers and organiza-
tons IN the country 1t differs from
the old system principally lii that the
lights flash on different but co -ordi-
mated time cycles, whereas formerly all
lights on a given street changed stimuli
taneously.
Increases ''Ware Band"
The particular advantage Of this, A.
@. Seller. TRAFFIC Department engineer,
explained, Is that it increases the
wave band" or length of the groups
OF vehicles passing an intersection be-
tween changes of lights, thereby in
larging the streets traffic capacity
Also, under the new system, amber
lights viii fash at half-Second inter
walls from midnight to o'clock in the
morning, warning motorists Of the in
tersections.
The Rhode Island avenue experiment
incorporates the skip amber" system,
now being tried out at several inter-
sections throughout the city. BY this is
meant that the amber light win show
only when the signal is changing from
green to red. The change from red to
green viii be without warning. This is
intended to prevent drivers from
beating the light"
Mr.. Van Duzer said he intended to
proceed Immediately to advertise for
bids for other equipment of the flexible
type II the experiment on Rhode Island
avenue proves a success. Twenty five
thousand dollars was made available by
the last Congress and approximately
$1,000 was spent on Rhode Island ave-
nue..
Plan 100 Installations.
The trafic director estimated that
the rest of the appropriation would be
sufficient to install the flexible system
at 100 downtown intersections. When
may be extended throughout the en-
tire city.
The new system is in complete ac-
cord with the recommendations Of the
National Conference of Street and
Highway Safety, down to the most
minute detail" Mr.. Seller, who has Su-
pervised the installation, declared.
1T differs from the old, or limited,
progressive system, in that it is now
possible to adjust the timing In ac-
cordance with the flow of traffic at a
particular street intersection, whereas
formerly the time divisions throughout
the entire street were equal, disregard
ing completely heavy or light cross traf-
fic," he continued. The installation
and timing has taken approximately 10
days, since 1t was necessary to make
traflc counts at each of the intersec-
tons before determining the time Pc
RODS"
Cycles Vary.
1.-THE time cycles vary at almost
every intersection, but the average is
about 40 seconds for Rhode Island
avenue traff1e to 20 seconds for cross
streets. BY this means of having the
lights fash at different times it is pos
sible to obtain an uninterrupted flow
of traffic. The new system also dis
courages speeding, since the motorist
travelling at a speed greater than %
miles per hour will find himself run
ming into red light. He must main
tain 22-mlle rate, however, or he Will
miss the lights
The great advantage over the old
system lies in the increase of the traffic
wave band. BY wave band is meant
the groups in which vehicles travel.
Under the limited system these groups
contained only II or IL cars, while with
the flexible system they are increased
to 10 to %.
Each light has a separate timing
device which regulates its time cycle.
A master timer, however, controls and
co-ordinates the entire system. This
master timer starts the amber flashing
at midnight and automatically changes
back to red and green at o'clock in
the morning.
THE flexible system has been in use
in the Chicago loop district for more
than i've years, where it has been found
highly successful. 1t now Is being in
stalled on some streets in New York