Show Lights Light Alone Cant Can't Solve Peak Traffic U IONAL light lights cannot move traffic traffic SIGNAL fic At t It Its peak In our larger cities lies satisfactorily says Edward S. S Jordan ordan representing the tho street ti-al- ti tic lie c committee of the National Auto Auto- Automobile Automobile mobile chamber of commerce In la the monthly bulletin of that body pub pub- published published this week Highway engineers rs and city traffic managers are beginning to learn what railroad authorities discovered some cars ago ago namely namely that signals will work rork for a certain volume of traffic but ut cannot handle handlo a peak volume of wise ross travel satisfactorily Railroads long ago arranged for separation of grades at busy points recognizing that the block signal system system system tem might serve as a B. warning but could not handle the problem of actually actu- actu actually ally Uy moving two lines of traffic cross- cross crossIng crossIng Ing ng each other ollier PROGRESSIVE CITIES Progressive cities titles are beginning to adopt separation of grades at busy highway intersections Detroit now has h as a separation of grades at East Grand Orand Boulevard and East Jeffer Jeffer- Jefferson Jefferson Jefferson son avenue In St. St Louis Louts there Is an pass over where the Boulevard parkway passes over a major street street- at the entrance to ire Belles park parle Bethlehem Pa has an elaborate pass over which handles traffic at five Intersections St St St. Joseph Mo has adopted grade separation as a a. major method of clearing traffic San Francisco has an pass over-pass at atthe atthe atthe the foot of Market street and the Embarcadero ro This city also has a pedestrian viaduct for the passengers passengers gers gen who enter or leave the Ferry building from the central business dis die district district let ti-let and the East Bay communities In Cincinnati there are 11 over over- overpasses overpasses passes where one street Is carried by a a. bridge or a a. viaduct over an an- another another other street In the tha case of thi city the original reason for the pass over was not for reasons of traffic but be because be- be because because cause of topography MOST USE FROM FRO STREETS There may be some cities clues where the main flow of traffic is mainly west east-west or mainly south north-south but bu buin butIn butIn in those communities where at an any point there is heavy flow of traffic 1 In four directions separation of grades Is Sa the ultimate logical solution This is simply a a. matter of com com- common common common mon sense In the use of street space Often orten the need in a city is not for ad ad- additional streets but for effective use of the highways that already exist exIst If a B. main thoroughfare is constantly constant interrupted by signal delays that tha street is useless during Its Idle period If we take a a. busy Intersection where the traffic flow Is approximately approximately equal In the wise cross-wise Ions and where the signal delay Is Isa Isa isa a minute at a time each street Is being used at only half Its capacity because it is Idle half the time In any study of signal systems the tha problem of grade separation should be included at the same time MODERN NEEDS NEEDS' Grade Grode separation docs does not replace the he general use of ot signals any more than railroad grade separation lees away with block signals our v grade separations at Intervals of pos pas possibly possibly J sibly eight blocks this would give clearance to the block and through cross town traffic and It would be necessary only to have very brief sig sig- signal signal sig- sig signal nal Intervals at Intervening blocks which could clear dear the local traffic In Ina a a. short time The Tho whole problem of grade sep sep- separation separation separation both for intersecting high high- highways highways highways ways and for railroads needs new de designing de- de designing designing signing to meet modem requirements In many parts of the west est for In Instance In- In instance stance stancer one finds that the railroad warning signs have ha never been moved from right next to the track where they were established In the horse drawn buggy days Education punishment of the reckless reck reck- reckless reckless less and strict law enforcement are important In the improvement of our traffic facilities but we must always remember that we are dealing with the adventurous adventurous' and constitutionally heedless nature of the human being Accordingly the engineering means of protection should be applied and the separation of grades Is s an Im im- Important important important step The record of motor fatalities for forthe forthe forthe the first six months of this year Is b bIn un unfavorable un- un unfavorable favorable f In most of the larger com com- communities Only by engineering meth meth- methods methods methods by making the highways actually safer can wb expect ct to meet the addi addi- additional additional additional problem of increased population and increased transportation Engi Engi- Engineering Engineering Engineering science has helped to meet the growing problems In all walks of life and is Just beginning to operate In the field of designing city streets to meet modern vehicular needs |