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The Robot Traffic Cop comes to Town

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 1929 traffic system

The Robot Traffic Cop comes to Town

AVERY McBEE - The Sun (1837-1989); May 12, 1929; pg. SM4

The Robot Traffic Cop comes to Town

Another automatic device for vehicular regulation appears

Baltimore is about to install several units of a new traffic dispatching system which, to those who have seen it in operation seems almost human; more than human and some of its aspects of controlling the ebb and flow of vehicles.

The interesting point about this new system is that it does not direct traffic so much and all of the advantages of the electric signal and combine them, without manifesting any of their disadvantages.

Of course, a score of questions immediately leaped up for an answer when the system is outlined. The idea first was demonstrated here several months ago one little model board of a street intersection, toy cars being used for illustration. Police Commissioner Charles D. Gaither, inspector George E. Lurz, head of the traffic division of the Police Department, and a number of cities an automobile club officials and private citizens were present to watch the demonstration. The idea seemed almost too good to be true, and most of those present wisely reserve judgment until they could see the system in actual operation.

For that purpose Commissioner Gaither, Inspector Lurz, Nathan L. Smith, city highways engineer; H. M. Lucius, secretary of the automobile club of Marilyn and several other persons journeyed to Wilmington to watch the second day of operation of the signal system there. Upon his return, the Commissioner announced that the idea would be tried out in Baltimore as soon as engineers could survey some important points in this city and install the devices.

Mr. Gaither, however, is not so sanguine over the device as a control for traffic at some of the heaviest of downtown intersections. While he grants that the signal would work, he believes that an equally heavy flow on both the streets intersecting streets during a busy day would force the lights to do just what the present arbitrary system is doing-give green on each of the streets in equal proportion to the other. While there would be brakes in the line, he thinks that the value of catching up the small bits of lost motion would not equal the difference in operating expense between the present and the new system.

However, the Commissioner is confident that other downtown points might will be handled with this system, and the engineers already are surveying some important points against the possibility of installation. It already has been decided definitely to install the control at Park Circle, where six streets Brady eight, Karen both rail and motor traffic, and it gay, MONUMENT and Asquith streets, a difficult five-point intersection can all kinds of traffic.

Mr. Lucius representing the motorist was impressed with the invention and expressed the belief that the motorist themselves would be pleased with the arrangement and would not dread these signals as they do the arbitrarily-timed lights that cause such a waste of time.

The Department of Public Safety, the traffic governing body of Wilmington, is immensely pleased with its new controller. After a week of operations George B. Black, superintendent of public safety, declared that vehicular movement was satisfactory under all conditions and that, except for the need of a readjustment at one point, there has been no hitch since the dispatcher has been installed, lost the motion having been particularly eliminated and automatic control mastering every situation.

The brain of the system is a little box that is placed on the sidewalk at the intersection. This box connects with contacts in the street bed setback from what each intersection and also with the lights, which can be of any type now in use. The distance at which the contacts are placed from the corner is determined entirely by the speed at which it is desired to move traffic – the further away from the contact, the faster the flow of cars. Where Streetcar traffic is an element, another contact is fixed on the trolley wire and is actuated the trolley wheel passing under it after passengers have been discharged and taken on.

When an automobile approaches the intersection it rolls over its contact and if new traffic is approaching from the other Street, it will get a green light before it reaches the corner. If two cars moving at right angle strike their trails at the same instant, the light will not hesitate, but it will decide between the two, giving right away to one car long enough for it to cross, returning to give the other car passage as soon as the first machine has crossed the street or made its turn.

What happens when a car runs over the contact is this: an impulse is transmitted to the control box or “electric eye.” If conditions are right, the impulse will be relayed immediately to the signal; if not, the impulse will be “filed” and do note of it will be taken at the proper time.

Thus if the traffic is heavy on one street and cars are clicking over trials on that street one after another, while traffic on the alternating Street is light, then the signal will recognize the heavy line and stay green to that traffic for a certain lifetime. If, however, one or two or three cars have come in from the other Street and are waiting for recognition, the signal will change over after, say 30 or 40 seconds, to clear these cars, returning immediately to the rush of the heavy line along again.

If traffic is extremely heavy on both of the intersecting streets the contacts are clicking constantly, the device recognizes first one line and then the other, giving right away and partially until there is a break in one of the lines. But the moment there is a break, then the signal switch is over and gives heavy traffic the green to hurry it through.

In the “electric eye,” there are a number of little levers which can adjust the system to any desired condition. For instance, if it is desired to give one street a longer time at certain times of the day than the other, a lever will be switched to allow that, say, 40 or 50 seconds or minutes before the light changes to pick up cars straddling in front of the minor Street.

Or the signal can be made to show green always the one street and make changes only when a car comes in from the other Street, never allowing side traffic, however, to usurp the preponderance of time from the main artery.

One important phase of the new idea is that it places no burden on the brain of the motorist since the operation of the signal is entirely automatic. The driver does not have to blow the horn or make any special effort to bid for recognition. He cannot help running over the treadle as long as he is on the right-hand side of the street, so the system works as well for the most witless driver and for the stranger as it does for the most skilled motorist and one entirely familiar with the system.

The control box is said to be adjustable to any kind of traffic situation. In Wilmington, for example, a bad situation has been brought under control at the intersection of Delaware Ave., Pennsylvania Avenue and Van Buren streets. At this point to main traffic arteries converge at a 45° angle into one wide street and at the point of intersection, both streets are crossed by a small Street. This makes a five-point intersection.

The new system handles traffic at this point in three phases, gauged entirely by cars running over their contacts. Traffic coming on the two streets that meet at a 45° angle move in one phase; traffic on the broad thoroughfare that is formed by the convergence of these two arteries moves in another phase, and traffic that moves out of each side of the smaller thoroughfare moves in a third phase.

The Baltimore delegation was frankly skeptical of the ability of the system to handle certain situations, but his questions brought a prompt answer, followed by a demonstration. Commissioner Gaither was solicitous of the welfare of the pedestrians, but engineers in charge of the Wilmington installation pointed out that people on foot are being encouraged to watch traffic instead of the signals, for if they start across with traffic it is moving in one direction they know that they are safe as long as there are cars in the intersection when traffic is cleared they know that the signal will change and they can decide what is best to do, whether to quicken their pace, turn back or standstill. All of which, it is pointed out, is more comprehensible than the arbitrary signals, where the pedestrians couldn't gauge and which often changed when he or she were in the middle of the intersection.

Anxiety was allayed also as to the serviceability of the street contacts in winter, for New Haven, Connecticut, has had these units to the past winter and heavy snow and ice and, it is said, not one was rendered ineffective.

One of the first questions that was asked was what would happen if a car broke down on one of the contacts. This was answered by one of the engineers, who said that “the worst that could happen would be for the signal to become an arbitrary signal system, for it would keep traffic running on the street only for the time allowed it, returning to the other Street after 30 or 40 seconds to pick up that traffic, and returning to the street that was claiming green by the car standing on the contact.” Naturally, this would be a temporary condition.

Several the dispatchers have been placed on the DuPont highway between Baltimore and Wilmington to govern important points.

On the main highway, the road contacts are set back at 230 feet so cars may keep up their speed and find no necessity of stopping or slowing at the intersection. Treadle’s at the crossroads are set closer to the corners said they may one no chance of putting into main traffic at too great a speed.

Baltimore Police Department
242 W. 29th St., Baltimore, MD.
Emergencies: 9-1-1  Non-emergencies: 410-396-2037

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Again please contact Ret. Det. Kenny Driscoll if you have pictures of you, your family, or other members of the Baltimore Police Department and wish to see them remembered here on this tribute site. We are anxious to honor the fine men and women who have served this fine police department. Ret. Det. Kenny Driscoll can be reached at  This email address is being protected from spambots. You need JavaScript enabled to view it. - Like us on Facebook, or contact us for a mailing address 

Copyright © 2002 Baltimore City Police History - Ret Det Kenny Driscoll

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