US2016325A - Traffic control system - Google Patents

Description

Oct. 8, 1935. c, GEER 2,016,325

TRAFFIC CONTROL SYSTEM Filed NOV. 1, 1930 [If/0 l0 12 Fig .2 6

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INVENTOR.

CHARLES D. 65.52,

"M, emu M ATTORNEYS.

Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE TRAFFIC CONTROL SYSTEM necticnt Application November 1, 1930, Serial No. 492,731 7 Claims. (Cl. I'M- 337) This invention relates to a functionally and structurally improved trafllc control system and apparatus forming such system.

It is an object of the invention to provide a system and apparatus of the nature stated capable of use in numerous different associations but primarily intended to be employed at the point of intersection of two vehicle lanes and specifically vehicle lanes of the automobile type. Where so employed, the present apparatus will provide a system functioning in response to the flow and condition of traflic and which system will operate in an improved manner to prevent accidents at the point of intersection and will additionally expedite to a maximum extent the traffic flow.

A further object of the invention is that of furnishing an apparatus for controlling the flow of traffic in such manner that a vehicle or vehicles traversing one lane will have ample opportunity to negotiate the intersection before right of way is transferred to the other vehicle lane.

Another object is that of furnishing an apparatus of this character, the parts of which will be relatively few in number and individually simple and rugged in construction, these parts functioning over long periods of time with freedom from mechanical and electrical difliculties.

With these and other objects in mind, reference is had to the attached sheet of drawings illustrating one practical embodiment of the invention, and in which:

Fig. 1 shows diagramatically the intersection of two vehicle lanes and moreover illustrates an apparatus embodying the present invention and in association with such lanes; and

Fig. 2 is a similar view of a detailed layout of apparatus suitable to achieve the results to be accomplished by the present invention.

For the sake of simplicity of illustration, the present invention has been shown as embodied in a, traflic control system installed at the point of intersection of a cross street and main highway. In the drawing, the latter is indicated at A and the cross street is designated B. As hereinafter described and in line with this example, vehicle actuated controls are shown only in the cross street. However, under actual installation conditions, these controls will usually although not necessarily be in both Streets or in any further number of streets which may exist at the point of intersection.

Thus as illustrated, a signal 5 is disposed conveniently adjacent the point of intersection of the two lanes and has signal lights visible to vehicles moving along such lanes and approaching the intersection. These lights have been indicated at 6 to 9 inclusive in Fig. 2 and embrace preferably two green lights and two red lights, the former indicating right of way and the latter signalling a halt to the vehicles. To this end, these lights are preferably colored green and red respectively which coloration may be achieved by the use of colored'bulbs and/or lenses or in any other suitable manner. Moreover; if the present invention is embraced in a system of the nature afore referred to, the vehicle actuated or responsive controls Ill or II are disposed in only the cross street. While the signalling means a may be of any desired character and the vehicle actuated controls may also embrace any mechanism suitable to operate in response to the passage of a vehicle along the vehicle lane, it is preferred that such controls be in the nature of pressure operated switches which incident to the passage ofv a vehicle function in order to close a circuit. It will be observed that a plurality of these switches are, in the present exemplification, associated with the cross street. These switches are connected in parallel and arranged two to each side of the intersection. Accordingly, actuation of one of these controls will close the circuit common to all of them. For the sake of simplicity only two controls have been shown in Fig. 2 and indicated by the reference numeral l l.

The functionings of the signalling means 5 in response to actuations of the controls l0 and H are governed by a timer or control mechanism l2, the detailed construction of which has been shown in Fig. 2. In this view and as afore brought out, the several vehicle actuated controls ID are shown in the form of parallel switches l I. A closing of either switch permits current to flow from lead I3 through quick acting relay [4 and thus to lead IS. The leads l3 and I5 are connected to a source of power supply (not shown) and the armature of the relay It serves to move a switch l6 from engagement with the contact arranged at the end of lead I! into engagement with the contact at the end of lead I8.

The parts as shown in Fig. 2 die in a normal position, but an energization of the relay will as afore stated move the switch ll which will permit current to flow from lead I! through lead It, thence through relay l8 and so through lead 22 to lead It. This will serve to operate and lock in relay ll by virtue of the fact that the armatures controlled thereby will shift the switches 2| and 22 into engagement with contacts forming parts of leads 22 and 24 respectively. Thus even though the switch it move rapidly out of engagement with the contact of lead ll, current will now flow through lead 25, a switch 28 interposed therein, lead 22, switch 2|, relay I! and so through lead 20 to lead I5. As afore brought out, the switch 22 moves into engagement with a contact associated with the lead 24 and current willnow flow through this lead and relay 21, lead 20 and switch 2! from lead ll. Consequently, switches 40 and II will move to closed positions, thus through the former permitting current to flow through lead 32 and relay 23 interposed therein, through this switch, lead 24, switch 22 and so to lead It. With the closing of switch 21, current may flow through lead 34, switch 35 interposed therein, and thence through switch II and so to lead II.

Relays i 4, i9, 21 and 88 are of the substantially instantaneous types. The switches 26, 2| and 29 are controlled by time delayed relays 38, 21 and 38 which may conveniently be of the oil dash pot type. In the embodiment under consideration, the first of these latter relays is set to open after five seconds, the second relay is set to open after thirty seconds and the third relay is set to close thirty seconds after having been continuously energized. All three relays return to their deenergized position substantially instantly. However, this time factor may be varied largely according to the conditions of installation which are met with. Finally, it will be observed that the lead I! may also supply current through the lead 29 to the signalling means or lights I and 9 interposed therein, and thence through switch 40 to the lead It. This switch is controlled by relay 23 as is also a switch 4| interposed in a lead 42 within which there is additionally interposed the relay ll. Finally, it will be observed that the relay 23 shifts the switch 40 to a point at which it engages the contact associated with lead 43 within which are interposed thesignalling means or lights 8 and 1 which latter when energized served to signal Stop to.the highway and to accord right of way to the cross street.

With a set up of the parts such as that herewith illustrated, it will be obvious as afore brought out that an energization of the relay l4 follows each closing of the switch ll. Also as afore brought out, this results in a locking in of the relay I! in turn energizing relay 21 to permit current to flow through lead 32 and relay 13 from lead It to lead I 5. Consequently, an immediate shifting of the'switches 40 and 4| follows and right of .way is transferred from the highway to the cross street by virtue of the extinguishing of lights I and 8 and the energizing of lights 6 and 1.v The energizing of the relay 33 will also cause circuit through relay 38 to be broken and the switch 29 will consequently move out of engagement with the contact at the end of the lead 28.

All of this will occur under usual conditions of operation upon a vehicle approaching over cross street B and operating the first vehicle actuated control. of the pair. Under the setting of the parts and with relays i9 and 21 energized, relay 28 will be potentialized to operate in five seconds. However, due to the fact that the vehicle still has to negotiate and operate the second control, it will be obvious that this relay will be reset substantially instantly before the vehicle reaches the point of intersection. In other words, due to the closing of the second switch II, the relay l4 will again be energized to shift the switch I and thus break the circuit through relay 3', the latter accordingly being reset to require the full time interval before it operates. Upon the expiration of such time interval, the switch 24 is open and current will accordingly no longer flow through lead 23 thus causing a deenergization of relay' l9 and permitting the switches 2| and 22 of the latter to open. Consequently, relay 21 will also be deenergized and as a result, relay 2! will be deenergized so that switches 40 and 4| will move back to the positions illustrated in which first current is being supplied to relay 38 and secondly the right of way is transferred from the cross street in favor of the highway due to the extinguishing of signals 6 and 1 and the reinstatement of signals 8 and 9.

If thereupon a further vehicle approaches over lane B and operates the vehicle actuated controls resulting in a closing of the switch Ii, relay i4 will function to again operate switch I! and thus lock in relay IS in the manner afore described. However, due to the fact that relay 2| requires-in the example given-thirty seconds to shift its armature so that the circuit through wire 2! is closed the switch 29 will be open and consequently the relay 21 can not be energized. Accordingly, no change in condition results despite the presence of a vehicle and the latter must wait a full thirty second period before transfer of right of way occurs. At the end of this period, relay ll shifts switch 29 to closed position and thereupon the relay 21 functions to operate relay 3! so as to transfer right of way in the manner afore described and the cycle of. operations is again repeated.

However, it will be recalled that the vehicle has come to a standstill after operating the first vehicle actuated control. Ordinarily the vehicle could gather sufficient momentum to negotiate the intersection five seconds after the transfer of right of way, but, while this vehicle would be able to get clear of. the intersection before the right of way was retransferred, it will be obvious that in the case of a second, third and possibly more vehicles having passed the distant vehicle actuated control and awaiting suchright of way, the delay factor of getting these vehicles under way after transfer of right of way would be such that they could not conceivably negotiate the intersection within the time interval allowed without the provision of the second vehicle actuatcd control. Accordingly, immediately in advance of the intersection, the second vehicle actuated control is arranged and therefore the second, third and other vehicles awaiting right of way will operate such control, causing a five second delay interval in the retransfer of right of way. Thus, all the vehicles will have ample time to negotiate the intersection, it being understood that each time the relay I 4 operates, the relay 38 will be reset.

It would appear that the second vehicle actuated control might perform all necessary functions and that the distant control might be dispensed with. Such is not the case. A vehicle should register its presence sufficiently in advance of arriving at the intersection so that if it receives right of way immediatelyitcan avail itself thereof before deceleration is necessary; On the other hand, if the vehicle will have to await right of way, it should have registered its pres-'- ence before deceleration begins, so'that ample space is available for stopping. I i v Occasionally, a very heavy flow of traffic may occur on the cross street and this-might prevent the highway from receiving right of way fora long period of time. However, due to the provision of relay 31, it will be obvious that right of way may not be retained in favorof the cross street for an indefinite period. 'As illustrated and described, this relay will function after thirty seconds to open the switch 35. This will cause the circuit through relay 21 to be interrupted, thus returning the signal to normal condition and closing the circuitthrough relay 38. Consequently, the parts will return to their normal condition except that relay l9 will remain locked in and, as a result, right of way whichhas been transferred in favor of the highway will be retransferred back to the cross street'afte'r thirty seconds.

It will be understood that, the innermost vehicle actuated controls, 1, e. those controls which are nearest to the intersection, might be disposed at points relatively remote therefrom. For example, these controls might be anywhere from 25 to I feet from the intersection while the outermost controls might be as much as 200 to 300 feet away. This will be particularly true where the present invention is incorporated in a layout of apparatus to be installed at cross streets where high trafllc speeds may occasionally be encountered. It will be obvious that in addition to the vehicle actuated controls illustrated-and as afore brought out--that the vehicle actuated controls will exist in the second lane. Where the innermost controls are substantially immediately adjacent the intersection, the advantages of the reset period and the manner in which the ap- ,iaratus will function in the case of a number of vehicles awaiting right of way will be obvious. Where the innermost controls are somewhat spaced from the point of intersection, it will be apparent that at best only a few vehicles awaiting right of way will move beyond the innermost controls and these vehicles will have opportunity to negotiate the intersection during the minimum period granted when right of way is given. If further vehicles are awaiting the right of way beyond the innermost controls they accordingly in traversing such controls will reset the apparatus to extend the minimum period.

Summarized, it will be apparent that with the parts in the position illustrated in Fig. 2, a vehicle approaching over the cross street will cause-incident to an operation of the first vehicle actuated control-a substantially immediate transfer of right of way in favor of the cross "street. If further vehicles are following the first named vehicle or are approaching over the cross street in the opposite direction and within a sumciently close time interval, these other vehiclesincident to operation of the controlswill prolong the right of way for a period of time adequate to permit their crossing the intersection. In this manner, the cross street right of way may be maintained according to the present setting of the parts up to a period of thirty seconds. At this time, regardless of whether further vehicles on the cross street wish the right of way, the right of way will be transferred to the highway. However, if such right of way is desired at that time the system will iirememberittha-ipresence of such vehicles incidenttoithe lockingcin 'of the relay It or a functionally equivalent structureiso that at the end of thewhighwaysarightr of siway period, a retransfer of rightof-zway itb theicrbss e street will occur. The sa'meresult willlbe trueiin the case of vehicles arriving during the liighway right of way period. 1 By virtue of providing a multiplicityz'of .velii actuated controls, the following salient advantages among others are derived: firstg in the-case of a vehicle moving over the' 'cross street'toward the intersection, the right of waiy giv' wane crossstreet will be retalned for a period ropontional to the speed of the'vehiclei Iri' othe .words, 1 5 the spacing of the vehicle somerset-sham their distance from the point of intrseotiom etc be so proportioned'that one may safely sayhat no vehicle will require less thanslightlyinexcess of five seconds tonegotiate the intersection amt having operated the first vehicle actuate trol. Consequently, such vehicle will oprat first control and whileit continues' 't'o mo i the cross street, right of way will be" transferred 7 r for a five second period incident to'flthe setting of the relay 36. This relay however'will b reset by the same vehicle incident to'operation the second control and this resetting will be for ire period. Now, assuming as More brought out, M, that the vehicle is movingathighspeed, w'' 'inii'y arbitrarily say, for the sake of example, thatbril'y one second will be required for it to negotiate tlie 'distance between the first and second 'coiiti'ol.

The second control resets the right'of'way period for an additional five seconds. Consequentlyflthie entire right of way period in favor of-the crj'os's street will be six seconds. "In the'caseofaslow moving vehicle, four seconds maybe required tween operation of the first controland the' se ond control, making a total of nine second Second, in the case of a vehicle arrivih' at the time that right of way is transferred aclr to the highway, or during the right ofway pe- .riod of the highway, no trahsrer' r rig ts: way

to the cross street will result despite the operation of the vehicle actuated control. However, afore brought out, the system will remember'thisf. After the expiration of the highway righ 'of way period, the system will accordingly-transfer right of way back to the cross street. It will "here"- membcred that the vehicle is at a standstill, and would have five seconds to negotiate thefintersection. This would be sufficient for one or passibly two vehicles, but if further vehicls'arrived during the highway right of way period andwere awaiting right of way, five seconds would not be suificient time for them to negotiate the intersection. However, by virtue of providing the second control, five seconds-in the example givenis allowed from the time this control is operated until right of way retransfers. Accordingly,.arn'- ple opportunity will exist for all additional waiting vehicles to operate this second control and to negotiate the intersection up to the maximum right of way period for which the relay 3] orits equivalent structure is set. I I Under varying conditions, the spacingof-the vehicle actuated controls would be changed in many respects and the proximity of these controls to the point of intersection would also be altered. Obviously, in lieu of the dash pot relays referred to, any other suitable mechanism might be employed and as afore brought out, the system might be altered according to the particular needs of the installation without departing from the spirit of the invention as defined by the claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. A traiiic control system including signalling means to be disposed adjacent the intersection of two vehicle lanes and to accord and interrupt right of way to vehicles moving over said lanes, control means connected to said signalling means to cause such operation thereof and a pair of spaced vehicle-responsive controls disposed in one lane to one side and in advance of said intersectlon, said vehicle-responsive controls being connected to said control means and adapted to be sequentially operated by a vehicle approaching the intersection over such lane and means forming a part of said control means whereby operation of the first vehicle-responsive control causes transfer of right of way indication to the lane in which said controls are disposed and maintains said right of way indication for a period of time. and actuation of the second vehicle responsive control causing said control means to lengthen such period of right of way indication.

2. A tramc control system including, in combination, signalling means to be disposed at the intersection of a plurality of tramc lanes and to alternately accord and interrupt right of way to tramc moving over said lanes and through said intersection, timing means controlling the operation of said signalling means, a mum: responsive caitrol disposed in one of said lanes and connected to said timing means to accord when actuated through said signalling means right of way to said lane for a minimum period, said traiiic responsive control being located at a point relatively remote from the intersection and a further traiiic responsive control connected to said timer to extend when actuated the right of way period of such lane, said further control being disposed at a point relatively close to the intersection.

8. A traiilc control system including, in combination, signalling means to be disposed at the intersection of a plurality of traiiic lanes and to alternately accord and interrupt right of way to tramc moving over said lanes and through said intersection, timing means controlling the operation of said signalling means, a trai'iic responsive control disposed in one of said lanes and connected to said timing means to accord when actuated through said signalling means right of way to said lane for a minimum period, said traffic responsive control being located at a point relatively remote from the intersection and a further trams responsive control connected to said timer to extend when actuated the right of way period of such lane, said further control being disposed at a point relatively close to the intersection, and means forming a part of said timing means for terminating the right of way period of said lane.

4. A traiiic control system including, in combination, signalling means to be disposed at the intersection of a plurality of trainc lanes and to alternately accord and interrupt right of way to traiiic moving over said lanes and through said intersection, timing means controlling the operation of said signalling means, a traiiic actuated control disposed in one of said lanes at a point relatively remote from the intersection and connected to said timing means to accord when actuated through said signalling means right of way to said lane for a minimum period, means forming a part of id timing means to automatically transfer through said signalling means the right of way from said lane to another lane upon the expiration of said minimum period, and a further traffic actuated control connected to said timer to prevent, upon actuation, the automatic transs fer at the end of the said period, and to extend the right of way period of such first named lane beyond the said minimum period, said further control being disposed at a point relatively close to the intersection. l

5. A traiiic control system including, in combination, signalling means to be disposed at the intersection of a plurality of tramc lanes and to alternately accord and interrupt right of way to traffic moving over said lanes and through said intersection, timing means controlling the operation of said signalling means, a traflic responsive control disposed in one of said lanes and connected to said timing means to accord when actuated through said signalling means right of way to said lane for a minimum period, means forming a part of said timing means to automatically transfer through said signalling means the right of way from said lane to another lane upon the expiration of said minimum period, further means forming a part of said timing means to maintain the transferred right of way in favor of said second lane for a determined period, the traflic responsive control of said first named lane being located at a point relatively remote from the intersection and a further traflic responsive control connected to said timer to prevent, upon actuation, the automatic transfer of right-of-way at the end of such minimum period, and to extend the period of such first named lane, said 36 further control being disposed at a point relatively close to the intersection.

6. A traiiic control system including, in combination, signalling means to be disposed at the intersection of a plurality of traiiic lanes and to 40 alternately accord and interrupt right-of-way to traffic moving over said lanes and through said intersection, timing means controlling the operation of said signalling means, a traiiic actuated control disposed in one of said lanes at a point relatively remote from the intersection and connected to said timing means to accord, when actuated, through the signalling means, right of way to said lane for a minimum period, means forming a part of said timing means to automat- 60 ically transfer through said signalling means the right-of-way from said lane to another lane upon the expiration of said minimum period, and a further traiiic actuated control connected to said timer to prevent, upon actuation, the automatic transfer at the end of the said period, and to extend the right-of-way period of such first named lane beyond the said minimum period, said further control being disposed at a point relatively close to the intersection, and means forming a part of said timer to prevent continued extension of right-of-way to such first named lane beyond a predetermined period.

7. A trafiic control system including, in combination, signalling means to be disposed at the intersection of a plurality of traiiic lanes and to alternately accord and interrupt right-of-way to said lanes, timing means controlling the operation of said signalling means, a plurality of yehicle responsive controls disposed in one lane to 7 one side and in advance of said intersection, one of said controls being located relatively remote from the intersection and connected to said timing means so that when actuated while right-ofway is not accorded to the lane of said control tion, the right-of-way period for at least an interval sufiicient to permit passage of a vehicle to a control nearer the intersection and the control nearest the intersection, upon actuation extends through said timing means the right-of-way pe riod for a further interval sufiicient to allow passage of the vehicle across the intersection.

CHARLES D. GEER.

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