US2188348A - Traffic control system - Google Patents

Description

J'an. 30, 1940. H, A. HAUGH. JR

TRAFFIC CONTROL SYSTEM Filed April 23, 1930 4 Sheets-Sheet l YQ... 7. M

Jan.

H. Ai l-lAucsl-l- JR 2,188,348

TRAFFIC CONTROL SYSTEM Filed April 23, 1930' 4 Sheets-Sheet 2 lll l NVENTOR.

ATTORNEYS.

Jan. 30, 1940. H. A. HAUGH, JR 2,188,348

TRAFFIC CONTROL SYSTEM Filed Apri1'23, 1950 4 Sheets-Sheet 3 H. A, HAUGH, JR

TRAFFIC CONTROL SYSTEM nFan.. 30, 940.

4 Sheets-sheet 4 Filed April 25, 1930 ill) ' this end, in Fig.'4, three Patented Jan. 30, 1940 `UNITED STATES PATENT 'OFFICE s TRAFFIC cgLsYs'n-:M

to The Engineering and Research Corporation, New Haven, Conn., a corporation of Connecticut Application April'23, 193i), Serial No. 446,462 I 27 Claims. :(Cl. 177-339) v l v tion period furnished by -the yellow or amber provision; any desired `arrangeriientfrnight be This invention relates to a functionallyV and structurally improved traffic control system.

My copending application 227,490, filed October 20, 192:7, also relates to a traiilc control system and claims to any common subject matter appear in such copending application; the claims in the present application are directed to subject matter not claimed in the copending application.

It is anobject of the invention to provide a layout of apparatus by means of which traflic will be expeditiously and automatically handled so that a maximum trailic flow throughout various intersecting lanes may occur and without danger of conflict on the part of traflic moving in different directions.

While the present invention is capable of use in numerous different associations and is accordingly not to be regarded as limited to the following, it is in many respects of primary utility where three or more vehicle lanes merge andregardless of whether traffic after negotiating the intersection wishes to merge into another lane or continue along the same vehicle lane.

A further object of the invention is thatof providing an apparatus of extrem ely rugged and unitary construction which will function over long periods of `time with freedom from electrical and mechanical difficulties.

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

Fig. 1 is a planv view ofa timer by means of4 which the system may be operated;

Fig. 2 shows a diagrammatic layout of the circuit involved in thel present system;

Fig. 3 is a perspective view of the timer as shown in Fig. l; and

Fig. 4 is a perspective view showing a number of intersecting vehicle lanes, the trafic flow over which will be controlled by the present system.

As afore brought out, the present system is of particular utility when 'employed in connection with three or more intersecting vehicle lanes. To lanes have been shown. Moreover, with a view to providing a signalling means, a light signal has been illustrated which is in most respectspreferable and includes the `usual colored bulbs, reflectors and/or ienses,`by

means of which, for example, red, amber and. green may be shown. Obviously, the signalling means might be of any desired character best suited to the needs of the installation, and if-as is in most instances preferable-lights are employed, it

will be obvious that in lieu of the cauexample by the beam .provision might be resorted to.

`For example, all lights might be extinguished for a suitable interval; only the red light or lights might the red together with the green-might `be displayed; one or more of the signal indications provided by the lights might beintermittently energized to furnish a flash during this interval, etc.

etc.

With regard to the vehicle actuated controls,

there has been over which the vehicle matically to potentialize shown a series of pavement units Apasses in order autothe apparatus for aY 'To this end, the units i a circuit breaker which pressure of the vehicle traversingthe unit. Obviously, the reverse might betrue or a vehicle actuated control either deliberately manipulated from withinthe car as fol` from a headlight or spotlight or the sounding of ahorn might be employed, or a circuit sympathetic to the passage of a'vehicle along the lane might be furnished. Any number of other lcontrols will likewise be apparent asfor example that of employing a photoelectric cell against which a beamof light is directed and which beam is necessarily interrupted by the traversal of a vehicle over the lane.

With respect to the timer, it is to be understood that preferably the layout by the present invention is 4 otherl desired arrangement viously, however, any

might be adopted. Moreover,

timer might be of any of apparatus provided to be adhered t0. Ob-

the relays of the `desired character and de for adjusting their functioning to accord exactly to the conditions peculiar to the particular installation under consideration.

Having the foregoing to the drawings:

in mind and referring -Let A, B and C represent vthree streets or approaches to an intersection. Assume that a pre-i ponderance of left turns out of C make it inadvisable-topermit traffic to flow from both A and C at the same time.

The three phase multito allow traffic to flow from only one of these approaches at a time.

To state the case more specifically: With carsA moving through they no cars are permitted car is waiting to move the green light when A yields the either thru the cessation due to the expiration o intersection from A street, to` come out of B or C. If a from C it will be given green light of traffic on A street, or f the A street over-all be shown for'this interval; 5

as soon as A street has thence backto its initial limiting period. If, on the other hand, no car is waiting on C street but one is waiting on B street, the car on B street will be given the green light yielded its green light. The streets will, in a predetermined order, be given the opportunity to take the green light, but no street will take the light when the opportunity is offered unless cars are actually waiting on that street or no cars are waiting onany other street.

The system also remembers when it breaks a stream of trailic due to the expiration of the overall period and leaves a call for the green light on that street which insuresthat the right of way will return to that street after the other streets have been given their turn to take the green light.

Figures 1 and 2 show the,A details of the mech,- anism and the electrical circuit comprising one embodiment of this system. The specic condi- K tion of the mechanism shown is that which prevails whenthe green light is showing on B street and no cars'are waiting on either A street or C street.4

Referring to Figure .1,-F, M, andy P are insulated levers pinioned respectively at f, m. and

. p. When lever F is moved to the left so that the contacts to itsleft. are made and those to its right are broken, A street is given the opportunity to take the right of way. Similarly when lever M is moved in a like manner, B street is given the opportunity to take the green light.

vAnd when lever P is moved in a like manner, C

street has its opportunity to take the green light. The levers F, M, and P are operated by the cams shown on theshaft 9 tothe rear of the levers. These cams are fixed to the shaft and revolve with it. But they are angularly displaced so that as the shaft revolves at uniform speed the levers are moved in the order F, M, P. Each lever completes its cycle o f motion [from the position of rest as shown by lever F to the left until it reaches the position shown by lever M, position of rest) before the next one begins itsvcycle. This prevents more than onevflow of traic at a time.

lThe cam shaft is driven by the motor I', worm shaft II, worm wheel I2', clutch I3 and I6', and bevel gears I4 and I5'. The motor, the worm wheel and lone face I3' of the clutch run all the time. To the other face I6' of the clutch is attached the bevel gear I4' which engages bevel gear I5' on the cam shaft 9 and a disk having three projections I'I, each in turn engaging a paw1,I8'` operated by amagnet I9. The clutch pressure is so adjusted that if the pawl on the magnet armature were pulled away from the projection with which it engages motion would be transmitted from the motor thru the clutch to the cam shaft thus causing the levers F, Mjand P to move sequentially. However, when the armature is attracted to the magnet, thus engaging the pawl with one of the projections on the disk, the cam shaft will be stopped and the clutch will slip. The projections are so located that the cam shaft will be held in such a position that one of'the levers F, M, or P will be at its extreme position of travel as these projections, in coope'ation with the pawl. prevent further rotation of the shaft.

'Ihe magnet I9'r is'electrcally connected into the circuit of Figure 2 so that it will be energized when the lever corresponding to the street on which a car is waiting reaches its extreme left position and will then cause the armature the energizing of their coils.

to be attracted, thus causing the pawl to engage the projection which will hold this lever in its operated position. In Figure l the lever M is shown in that position. The magnet will now gized while the lever P was in motion hence lever P would go over and right back again after which lever F (corresponding to A street) would be moved. When F reached its extreme left position the magnet would be energized thus stopping the movement and allowing A street to have the right of way.

The operation of the system to achieve this result is as' follows:

Referring to Figure 2,-D, E, K, L, N, O, S and T are quick acting contact relays. W, X, Z are time delayed relays which operate at the end of a predetermined period of time following The relays W, X, and Z can be independently adjusted to fix the time between energization and operation.

F, M, and P represent the levers (shown also in Figure 1) which operate the contact system designated by these letters with a numerical subscript. For example, lever F toward the left will cause contacts FIS, F2I, F23,

connection respectively with F2, F4, F6, F8, FID, FIZ, FIA, FI6 and FIS. Lever M in Figure 2 is shown in its left hand position which gives B street the opportunity to take the green light. The condition of relays K and L shows that B street actually has the green light. When B street yields the green lights lever M will move toward the right returning its contact system to the con'dition shown in the case of the contact system associated with levers F and P.

Contacts DI and D2 represent the contacts in the pavement units, or vehicle actuated control of A street; KI and K2. those in B street; and NI and N2 represent those in C street.

Relays D and E record the passage of cars over the pavement units in A street. Relays K and L perform a similar function for B street and relays N and O do the same for C street.

ible to cars approaching the intersections from A street. Rb, Yb and Gb represent signal lights visible from B street and Rc, Yrand Gc represent those visible from C street.

The time delayed relays. by means of the contactsystem associated with levers F. M and P are connected into the circuits of cach street as it is given the green light. Their functions `are A as follows:

Time delayed relay W, when operated, xes the period during which a continuous stream of vehicles can hold the green light.

Time delayed relay X insures each vehicle a predetermined period during which to cross the intersection.

Time delayed relay Z governs the period during which the yellow light is displayed.

The operation of transferring the green light from one street to another is accomplished in the following manner. Suppose that B street has the green light and a car operated the pavement contact system on C street. Relays N, O and T will be operated. The operation of these relays so connects time delayed relays that the operation of relay X or relay W will act to yield the green light on B street by causing relay S to be deenergized. The opening of relay S turns out the green light on B street and turns on the B street yellow light at the same time energizing the time delayed relay Z. At the end of the time for which time delayed relay Z is set it will operate thereby opening the circuit to the B street yellow light and the circuit |13 to the clutch magnet I9. This causes clutch magnet armature to fall back thereby disengaging the pawl from the projection on the wheel attached to the shaft which, thru the bevel gear, moves the cam shaft. The clutch now stops slipping and the cam shaft revolves thus allo-wing lever M to return to its position of rest (with right contacts made and the left contacts broken).

This turns on the B street red light. The cam shaft continues to revolve until the next cam moves the lever P to its left position. During the period between the breaking of the left contact system of lever M and the making of the left contact systemfof the lever P, the time de- .layed relays W and X have been de-energized and are in their unoperated position. When the contacts to the left of lever P are closed, current passes thru the contact. system of relays O, X, and W to energize relay S which operates immediately. The operation of relay S energizes the clutch magnet which operates its armature causing the pawl to engage the next projection on the wheel, which projection is located in such a position that the cam shaft is stopped when lever P is at its extreme left position. This closes the left contact system of lever P, opens the right contact system of lever P, thus extinguishing the C street red light, .lighting the C street green light and connecting the time delayed relays W, X and Z into the C street circuits wherel they will now function just as they did when connected to the B street circuit.

To trace a transition in detail, let us start with the circuit in the condition shown in Figure 2. Assume that no cars operate the B street pavement contacts KI and K2 and that none are waiting 'on A or C streets. Relay K will remain de-energized thus keeping time delayed relay X energized by current flowing thru contacts K6 and K1, wire 29, contacts M15 and MIB,

wires 16 and |05, relay X, wire |02. contacts S3 and S4 and wires |01 and ||0. At the end of the time for which it is set relay X will operate causing armature X8 to make contact with X9 and armature X1 to break from contacts X5 and X6.

The separation ol' armature X1 from contact X6 opens one circuit feeding current to relay S as follows: wire 32, armature L4. contact. L3,

3 lWires 5| and 86, contacts M1, M8, wires 13, 89, 99, contact X6, armature X1, armature W2, contact WI, wire 91, relay S and wire ||0. But there is a circuit parallel to the one just described .which still keeps relay S energized. This second circuit passes thru the back contact of the T relay and may be traced as follows: wire 15, contacts M|3 i and M|4, wire 14, armature T2, contact Tl, wire 98, armature W2, contact WL wire- 91, relay S and wire ||0. The relay S will remain energized until its current is stopped thru either the separation of armature W2 from contact W| or armature T2 from contact TI. It is evident from an inspection of Figure 2 that relay T will be operated whenever a car has crossed a pavement unit on any street against a red light. For instance, assume that a car operates the pavement unit on C street; relay T will be energized and armature T2 will break from contact TI. This is accomplished as follows: a car operates the CV street pavement contact unit. causing current to ow so as to energize relay N `thru the following path: wire 38, contacts Nl and N2, wire 39, relay N and wires 40 and 4|. Armature N3 now makes with contact N4 and armature N6 breaks from contact N1 and makes with contact N5. Relay N will receive current to remain energized (after contacts NI and N2 have separated due to the passage of the vehicle) thru wires 4|, 40, 39, 42, armature N3, contact N4, wire 43, contacts P20 and PIS, wires 60 and 20. Relay O is now supplied with current thru wires 4|, armature N6, contact N5, vwires 44, 41, relay O and wire 46. Ar-

mature 0| now makes with contact O2 and armature O4 breaks from contact O5 and makes with contact O3. The operation of relay O energizes relay T thru the following circuit: wire 48. armature Ol, contact O2, wire 49,contacts P22, P2|, wire.63, relay T and wire |09. The operation of relay T causes armature T2 to break from Tl and make with contact T3. However, the fact that relay L is operated in Figure 2 does not provide a path for current to relay T because of the separation of contacts M2I and M22. It follows from these conditions that relay T will be operated whenevera car is waiting against a red light. The operation of any one of relays E, L, or O when a green or yellow light isshowing on its corresponding street, will not energize relay T because current in each of these circuits passes thru a set of contacts on the right side of the lever, which contacts will always be separated when said lever is at the left as it must be when the yellow or green light is displayed on the street to which its contact system is connected. Now both of the current paths feeding relay S are broken. One between contact TI and armature T2 because a car is waiting on C street and the other between contact X6 and armature X1, because no car has crossed the pavement unit on B street (which has the green light) during the period in which time delayed'relay X is set to operate. Hence relay S is de-.energized` Armature S6 now breaks contact With S5 and makes with contact S1 and S8, armature S3 breaks from contact S4 and armature S2 makes contact with SI. The separation of S6 from S5 extingushes the green light on B street which has been receiving current thru armature S6, Contact S5. Wire 62, contacts M4. M3, wires 36 and 31. The yellow light on B street is now supplied with current thru wires 31. 35 contacts M5. M6. wires 64, 88. Contact Z3. armature Z4. wire |00 contact Sl, armature S2. wires 89. 13. contacts M8. M1. wires 86, 5I. contact L3. armature L4, and wire 32. 'Iirne delayed relay Z is now energized thru wires I 06, |08, contact'S1 and armature S6. The separation of amature S3 from contact S4 did not cause time delayed relay X to be de-energized because armature X8 made contact with X9 when relay X operated. Thus before the path thru wires ||0, |01, armature S3, contact S4 and wire |02 to relay X was broken, it'was paralleled by the path thru wire I 03, armature X8 and contact X9.

At the end of the Aperiod for which it is set, time delayed relay Z operates causing armature Z4 to break from contact Z3, lthus extinguishing the B street yellow light for which the current path has Abeen traced thru armature Z4 and contact Z3. Armature Z2 also breaks from contact ZI thus releasing the clutch magnet which has been .energized thru wire 32, armature'L4, contact L3, wires 5|, and 86, contacts M1, M8, wires 13, 89, 99, armature Z2, contact Z-I, wire ||3 to clutch magnet, thence to positive power.

The clutch magnet armature now drops back, the pawl disengages from the wheel projection and'permits the cam shaft to revolve. The cam holding lever M in its left hand position revolves permitting lever M to be pulled intoits right hand position. This permits the following contacts to separate; MI from M2;M3 from M4, M5 from M6, M1 from M8, M9 from MIU, MII from M I8. The contacts which now make connection are: MIS with M20, M2'I with M22, M23 with M24,-.and M25 with M26.`

In Figure 2, itis noticeable that the contacts associated with the levers F, M and P are so located that `al1 contacts associated with a given lever are not operated at the same time. The contact system of lever F is in the position of its contacts relative to each other and relative to the lever F itself, at any given position in its cycle of operation 'exactly the same as the contact systems associated with levers M, and P whenr either of these levers -is at the same position in its cycle of operations.

Hence when lever M has moved to its extreme right position, its contact system will be in 'the same condition as that of the contact system associated with levers F and P as shown in Figure 2. From the positions of the corresponding contacts associated with lever F, it can be seen that as lever M moves to the right, the first change of condition in its contact system will be the separation of contacts M3 from M4, M5 from M6, and MII from MI2. The separation of M3 from M4 disconnects the green light on B street, and the separation of contact M5 from M6 disconnects the -B street yellow light so that neither of these lights will be energized during the process of giving the green light to another street.

The circuits feedingboth of these lights werev traced before, hence to avoid needless repetition they will not be traced again.

The separation of contact MII and MI2 opened the circuit which held. relay L energized.

- This circuit has been traced before which makes .it unnecessary to trace it again at this point.

Armature LI now 'breaks from contact L2 and armature L4 breaks from contact L3 and makes contact with vL5 thereby lighting the B street red light thru wire 32, armature L4, contact L5, and wires `33 and 31. Next, contact M| 9 makes contact with M20 and contact M25 makes contact with M26. Under the conditions assumed, i. e., a car waiting on C street and none on B street the closing' of these contacts has no immediate effect. on the system. The next occurrence in order of sequence is the separation of contact M1 from M8, M9 from MIO, MI3 from MI4, MI5

from MI6, M|1 from MI8 and the making of contacts M2| .with M224 and M23 with 24.

'Ihe separation of contact M1 from M8 and M9 from M|0 have no immediate effect on the system. The separation of MI3 from MI-4 deenergizes time delayed relay W causing Ait thus to return to its zero position.' Due to the fact that under the conditions assumed, this relay had not been energized long enough to operate, its return to the zero position has no immediate eiect on the system. The separation of contact MI5 from MIB and M|1 from MI8 de-energized time delayed relay X which was energized thru two parallel circuits with MI5 and MIS in one and M|1 and MI8 in the other. These-may be traced as follows: Wires 25, 26, armature K6, contact K1, wire 28, contact MI5, M|6, wires 16, |05, relay X, contact X9, armature X8 and wire |03. The other parallel circuit being armature S6, contact S8, wires 19, 18, contacts M|1, MI8,

wires 11., |05, relay X, contact X9, armature X8 and wire |03.

The making of contact M2I' with M22 has no immediate effect on the system as the circuit in which they are included has already been opened between armature LI and contact L2. The making of contact M23 with M24 likewise has no im- -`mediate elect on the system, nor does the making of armature X1 with contacts X5 and X6 have any immediate elect.

The condition of the system is now as follows:

Contact relays D, E, K, L, and S are in their unoperated positions. Contact relays N, O, and T are energizedand in their operated positions.

Time delayed relays W and X are in their unoperated positions and time delayed relay Z is in its operated position. Levers F, M and P are in their extreme right hand positions with all right hand contacts made and all left hand contactsopen. f

The clutch magnet is de-energized, its armature is back, the pawl is disengaged from the clutch wheel projections and the cam shaft is therefore revolving. The cam associated with lever M has just released this lever which is now in its right hand position. The cam associated with lever P is about to move lever P from its right hand position into its left hand position.

Lever P now moves to the left. The lrst contact change is the separation of P2| from P22 and P23 from P24. The separation of P2I from P22 de-energizes relay T, the current for which has previously been traced thru contacts P2|` and P22. Relay T gets no current thru either of the other two parallel paths as armatures EI and L| are separated respectively from contacts E2 and L2. Armature T2 now breaks contact with T3 and makes contact with TI. This has no immediate effect on the system. The separation of contacts P23 from contact P 24 extinguished the C street red light (Rc) which has been supplied with current thru wires 55, 52, 96, contacts P23, P24 and wire 56.

Next the following contacts make: Pl with P2, P1 with P8, P9` with PID, PI3 with PI4, P|5 with PIE, P|1 with PI8. The contact between PI and P2 has no immediate etect on the system inasmuch as at present, armature XII is separated from contact X|0 due to the fact that time delayed relay X is de-energized and reset to its zero position.

The making of contact P1 with P8, energized relay S thru the following path: wire 48, armature O4, contact O3, Wires 50 and 95, contacts P1, P9, wires 13. 89. '99, contact X0, armature X1, armature W2. contact WI, wire 91, relay S and wire H0.

Armature S2 now breaks` contact with Sl, armature S3 makes contact with S4. Armature S5 breaks contact with S1 and S8 and makes contact with S5.

'Time delayed relay Z is de-energized thru the separation of armature S6 from contact S1. The circuit energizing relay Z consisting of armature Si, Contact S1, wire |08, relay Z and wire |06.

Armature Z4 no-w makes contact with Z3 and armature Z2 makes contact with ZI. The cantact between armature Z4 and contact Z3 has no immediate'eifect on the system as this circuit has been broken by the separation ofV armature S2 from con-tact SI.

The clutch magnet is now energized thru wire 49, armature O4, contact O3, wires 50 and 95, contacts P1 and P0, wires 13, 89, 99, armature Z2, contact ZI and wire H3. The clutch magnet armature now pulls up and its pawl is brought ,y

into position to catch the next passing projection on the clutch Wheel. 'I'his projection is so located that it will stop the cam shaft (and hence thelever P) when lever P reaches its extreme left hand position.

Time delayed relay W is now energized thru wires H0, |01, armature S3, contact S4, wires |02, relay W, wire |04, switch W5, wire 14, contacts P|4, P|3 and wire 15. Y

As lever P continues toward the left contact P|9 separates from P20 and contact P25 separates from P26. The separation of P25 from P26 has no immediate effect on the system. The separation of P|9 from P20 de-energizes relay N, the holding current for which has previously traced thru this pair of contacts. Armature N3 now separates from contact N4 and armature N6 separates from contact N5 and makes contact with N1. The separation of armature N3 from contact N4 has no immediate effect on the system.

' The holding current for relay Owas ytraced thru a circuit including amature N6 and contact N5. The separation of these does not however de-energize relay O as this relay is now fed current thru another path including contacts P1, P8, P9 and P|0 which closed before relay N was deenergized. This new path feeding relay O is as follows: wire 48, armature O4, contact O3, wires 50, 95, contacts P1, P8, wires 13, 89, 99, contact X8, armature X1, contact X5, wires 8|, 1|, contacts PIO, P9, wires 9|, 92, 41, relay O and wire 46.

The .contact of armature N6 with N1 energizes time delayed relay X thru wire 4|, armature N6,

Contact N1, wire 45, contacts PIE, PIB, wires 16, |05, relay X, wire |02, contact S4, armature S3, and wires |01 and ||0.

'I'heA further movementv of lever P causes con- `tacts P3, P and P|| to make respectively with contacts P4, P5, and Pl2. The contact of P3 with P4 lights the C street green light (Gc) thru wire 55, Gc, wire 54, contacts P3, P4,- wires 62, ||4, contact S5, and armature S6. Themaking of contact P5 with P5 has no immediate eifect on the system. C street now has the right of way and a red signal light is exposed on all other streets.

This covers the operation .of the system to transfer the right of way from B street to C street.

It instead of a car calling for right of way by operating the pavement unit on C street. one had done so on A street, the transition oi.' right oi' way from B street to A street would have been the same with relays D and E with associated contacts substituted for relays N and O and `lever F with associated contacts substituted for lever P.

However, the location of the cams operating levers F, M and P is such that after the return of lever M and before the operation of lever F, lever P would have to be moved into its left hand position and returned to its right hand position of rest.

Bearing in mind that as we are now assuming thatv no car operated the C street pavement units, relays N and O would be in their unoperated positions as.v shown in Figure 2, we will trace the action of the system enough to show that the lever P would not, under the assumed conditions, stop in its left hand position and that the green light and the yellow light on C street would not be lighted nor would the C street red light be extinguished during this transition.

First to show. that lever P would not stop in its left position: Referring to the action of the system previously outlined in transferring the right of way from B street to C street, it was shown that the clutch magnet was operated to stop the cam shaft thru the releasing of time delayed relay Z due to the operation of relay S which receivedits energy thru a circuit including armature O4 and contact O3. Since relay O is now de-energized, armature O4 is not in contact with O3 and relay S is therefore not energized when lever P moves into its left hand position. The fact that relay S remains deenergized leaves relay Z energized and hence,

the circuit feeding the clutch magnet remains open between armature Z2 and contact ZI..

Hence, the clutch magnet remains de-energized,

the pawl does not engage the projection on the cam shaft wheel and the cam shaft continues to revolve thereby allowing lever P to return to its position of rest atv the right hand as it is shown in Figure 2. The c am shaft now continues to revolve until lever F is moved to its left hand position when it wllLbe stopped. The action which stops the cam shaft and that which extinguished the Afstreetfred *light and turns on the A street green .,is'f simllarto that outlined in explaining thetransitionirom `B street to C street, and may befollowed by substituting in that account each'part associated with A street for the corresponding part associated with C street; i

The C street redlight, the circuit for which was before traced thru contacts P23 and P24 is not extinguished this time when these contacts temporarily separate because it is fed thru the parallel circuit including wire 48, armature O4, contact O5, wire 52, Rc and wire 55.

vThe circuit for the yellow light on C street was previously traced thru armature Z4 and'contact Z3. Since relay Z remains energized while lever P is in its left position as we have just shown, the circuit to the C street yellow light remains open and Yc is not lighted.

The C street green light circuit'was previously traced thru contact S5 and armature SS. The fact that these remain separated while lever P is in its left hand position causes the C street green light to remain unlighted.

The cam shaft now continues to revolve until lever F has been operated to give A street the green light.

Earlier in this description, it was stated that time delayed relays W and X were connected into the circuit in such a way that they would always act to limit the time during which a given street could hold right of way. The transfer of the connections of these relays from one street to another has been traced in detail. We shall now consider the Way in which they act to limit the time during which a street can have the green light. Referring to Figure 2, which shows the system as it would be if B street had the right of way and no cars were waiting on either A or C streets, the relays W and X are as shown in this diagram connected through the contacts associated with lever M to the relays K and L which are controlled in part by vehicles operating'the B street pavement unit KI. First, to explain the action of time delayed relay X. The function of relay X as was mentioned before is to provide that any car which has crossed a pavement unit shall be given a certain pre-determined period during which to cross the intersection. Before discussing in detail how this is accomplished, it would be well to notice a few features of the construction of this relay. Armature XI| separates from contact XIO. The mere de-energization of relay X does not cause armature XII to separate from contact XIO, however. To have this separation take place it is necessary for relay X not only to be de-energized, but to have actually re-set itself to its zero position.

One of the functions of armature XII is to insure that a car which operates a pavement unit when it is approaching a green light shall be given its full protective period. In other words, to insure that time delayed relay X actually resets to its zero position rather than to be stopped part way back. To explain how this is accomplished, let us assume that relay X has been venergized over half of the period at the end of which it has been set to operate. Under these conditions, armatures and contacts associating with relay X will be in a position shown in Figure 2. This relay is now receiving its current through the following path: wires 25, 26, armature K6, contact K'I, wire 29, contacts MI5, MIS, wires 16, |05, relay X, wire |02, contact S4, armature S3, and wires and ||0.

A vehicle operating the B street pavement unit would cause KI to make with contact K2 thereby energizing relay K thru wire 2|, pavement unit KI, K2, wire 22, relay K, wires 24 and 25. Armature K3 now makes contact with K4 and armature KB breaks contact from K1 and makes contact with K5. The separation of armature K6 from contact KI de-energizes time delayed relay X, the circuit for which has just been traced thru this armature and contact. The completion of the circuit between armature K3 and contact K4 provides a path for current to keep relay K energized, even though the vehicle has passed allowing Kl to separate from K2, until time delayed relay X shall have actually set back to its zero position. 'I'he path for this holding current is as follows: Wires 25, 24 relay K, Wire 23, armature K3, contact K4, wire 2T, contacts MI and M2, wires 6I, 80, armature XI I, and contact XIO, When relay X has actually set back to its zero position, armature XI I separates as was explained previously from contact XIO thereby opening the circuit thru which relay K is kept energized; thus permitting armature K3 to separate from contact K4 and armature K6 to separate from contact K5 and make with contact K1. The making of armature K6 with contact K1 again energizes time delayed relay X.

y Another function of armature XII and contact XIO is to provide that relay K shall remain energized if a car crosses the B street pavement unit during the period when the right of way is leaving B street, namely, when the green light on B street has been extinguished and the yellow light, on B street is burning, warning tratlic that the red light is about to be shown. In order to accomplish this, contacts MI9 and M20 are so adjusted that as lever M moves to the right, MI9 will make with contact M20 before contact MI breaks from contact M2. It has been previously explained that relay X once it has operated to yield the right of way, locks itself in the operated position thru armature X8 and contact X9 until the lever (M, in this case) thru which this relay is energized has returned to its normal position after having yielded the right of way. Due to this fact, armature XI I remains in contact with XIO until contact MIS has made with contact M20. This insures current to keep relay K energized until the right of way shall have again returned to B street.

Time delayed relay W will also yield the right of way when it operates thru the separation of armature W2 from contact WI (armature W2 and contact WI are part of the circuit which has been previously traced for the energization of relay S, the release of which acts to yield the right of way). The circuit as shown in Figure 2 provides that relay W shall be energized as soon as right of way is given to any street and shall remain energized until such right of way is transferred to another street. The current for relay W can be traced in Figure 2 as follows :r wire 15, contacts MI3, MI4, wire 14, switch W5, wire |04, relay W, wire |02, contact S4, armature S3, and wire |01. When time delayed relay W operates, armature W3 makes contact with W4 before armature W2 breaks from contact WI. The connection between armature W3 and contact W4 provides an auxiliary circuit to keep relay W energized vafter a main circuit has been broken by the separation of armature S3 from contact S4. This circuit may be traced thru wires |03, IOI, armature W3 and contact W4 which circuit is in parallel with that feeding the relay thru armature S3 and contact S4. Due to the fact that time delayed relay W remains energized shown in Fig. 2, as long as right of way is given to any street, it is evident that it provides a limitation on a period during which a steady stream of cars can hold the right of way on any street. If switch W5 were thrown in the position indicated by the dotted lines, relay W would not be energized as soon as right of way was given to any street, but would; be energized only after a car had approached the intersection operating the vehicle actuated control provided by the pavement units on one of the streets showing a red light. An inspection of Figure 2 will show why this is so. 'Ihe current to energize relay W was traced thru wire 14, switch W5 and wire I 04. If switch W5 is thrown in the position indicated by the dotted lines, it is obvious that the current, in `order to get from Wire 14 into Wire |04 must pass thru armature T2 and contact T3. Armature T2 will be in contact with T3 only as has been previously explained when a car is waiting for right of way after having crossed a pavement unit, subsequent to which crossing, it was not given a full protective period of green light. A

4 cause the green light to be extinguished on the 1 car might cross the pavement unit on a given street against the green light-toward the end of the period of operation of time delayed relay W. If it should happen that relay W should act to yield the right of way before this car had been given the full protective period for crossing the intersection, the system is so arranged that the right of way will return to this street at the earliest possible moment to take this car across. It will be remembered that this protective period is fixed by time delayed relay X. In the case just mentioned, the car thru the operation of the pavement unit would re-set relay X thereby causing X1 to make with contacts X5 and X6. Let use assume that this car has approached the intersection from B street. Before it crosses the intersection, relay W acts to yield the right of Way. Under these conditions, the movement of lever M'to the right will not unlock relay L. It will be remembered that in the previous instance of the transfer of the right of way from B street to C street,`relay L was de-energized when contact MII separated from contact M|2. However, this time the separation of contact MII from M|2 will not open the circuit feeding relay L because of the fact that armature X1 kis making with contacts X5 and X6. Relay L` will, after contact M|| has broken from contactMl2, 4and before contact M25 has made with contact M26, be fed current thru the following circuit: wire 32, armature L4, contact L3, wires 5|, 66, contacts M1. MB, wires 13, 89, 99, contact X6; armature X1, contact X5, wire 8|, contacts MIU, M9, wires 83, 51, and 3|, relay L and wire 30. Before contact M1 separates from contact M8 and contact M9 separates from contact MIU, thus interrupting the circuit just outlined, contact M25 will have made contact with M26, thereby providing a new path for current to keep relay L energized before the old one is broken. This new unit may be traced as follows: wire 32, armature L4, contact L3, wires 5|, 85, contacts M25, M26, wires 84, 83, 51, 3|, relay L and wire 30. Relay L will therefore remain energized and cause the right of way to return to B street at the first available opportunity. The general plan by which provision is made for the yielding of the right of way may be roughly outlined as follows: as has been shown before, the releasing of relay S will act to yield the right of way on a given street, relay S will be released whenever armature W2 separates contact W| or when armature X1 has separated from contacts X5 and X6 and armature T2 has separated from contact TI.. Thus it will .be seen that the system as shown inFigure 2, theright'of way Willleave the given street `after it hasbeenv held by that street for a. predetermined period, thru the separation of armature W2 from contactWI. If at any time within this period, the last car to cross the pavement unithas been-given itsffull protective period and relay X hasoperated to separate armature X1 from contacts X5 and X6.V

relay S is still energized by current flowing thru armature T2 and contact TI. This means that when a stream of cars passing thru the intersection on a given street has crossed the intersection, the right of way will be transferred to any other street on which a car may approach without delay because of the fact that the oper-` ation of the pavement unit by said car will energize relay T thereby causing armature T2 to lseparate from contact T| and break the remaining circuit supplying current to relay S. This will street which has been holding the right of way and the yellow light to be shown thereon, alter which the red light willshcw, whereupon the right of way will be transferred to the street on which the car is waiting.

In the absence of trafllc`on any of the lanes, if it is assumed for instance that traffic was` last present and has just cleared on street B and the green signal is showing on street B with red signals on streets A and C as indicated in Figures l, 2 and 3, there are two modes of operation as follows:

A. With switch W5 in the up position as indicated in Figure 2, time delay relay W will be energized and'timing its interval before operating its contacts, and with proper time setting time delay relay X will have been energized for its full interval and will operate its contacts, separating X1 from X5 and X6. Since we are `assuming no further traflic on B time relay X will remain energized in this operated position.

Since we are assuming no traffic on A or C, relay T will remain deenergized with TI connected to T2. Now when relay W completes its time interval and operates its contacts, separating W2 from WI and connecting W3 with W4 the holding circuit for relay S is broken as already described, and relay S is deenergized, which in turn energizes relay Z through the closing of contacts SB and S1. The green signal on B is now extinguished and the yellow signal lighted for the time interval of time delay Z, as already described. At the end of its time interval relay Z operates its contacts, breaking'the circuit to the clutch f magnet |9 thus allowing the clutch pawl to re.-

lease and the cam shaft to rotate, and lever M to be restored to rest opening its left contacts and closing .its right contacts. The opening of contacts M|3M|4 deenergizes time relay W, which in turn closes contacts W2-W|; and the opening of contacts MI5- MIB and MI1-MI8 deenergizes relay X closing contacts X5-X1 and X6-X1. As soon as the next lever P is shifted to the left by the cani shaft, and contacts P|3P|4 are closed, the relay S is energized. The resulting opening of contacts SS--S1 deenergizes time relay Z, which in turn energizes the clutch magnet I9' by the closing of vcontacts Z| and Z2, causing the cam shaft to stop with the lever P in the left position, and giving the green signal to C street. The circuit energizing the clutch magnet may be traced as follows: wire IIB, magnet I9'. wires ||5, H3,

contact ZI, armature Z2, wire 99, contact X6,

armature X1, wires 1, 98, contact Tl, armature T2, wire 14, contact P|4P| 3, wire 15. Time relays W and Xr are now again energized and start timing the C street green interval. If there continues to be no traflic, relay W will again cause shift of the right of way at the end of its time street A or street C, the right of way being now 'on` street B as assumed above. Therefore, with j the switch W5 in this down position time relay Wwill remain deenergized and the right of way will remain indefinitely on street B in the absence of trailic on the other streets. This condiheldV on the former street tion is independent of the presence or absence of tramo on street B with the green signal. Although in the absence of B street traiilc the time relay X continues to be energized and thus opens its contacts X-X1 and XB-Xl at the end of its interval, the parallel circuit through the contacts Tl-T2, maintained as long as no traic approaches on streets A and C, will hold relay S energized and retain the right of way on street B.

'I'he same general conditions of operation described for right of way on street B apply when the right of way is on one of the other'streets, and if the right of way is shifted from street B to street C by the approach of a vehicle on street C for instance, then the right of way will remain on street C as long as there is no traffic present on streets A and B. Briefly stated, with the switch W5 in the down position the right of way remains on the street where it was lasty used by traiiic until it is required by traflic on another street. In addition the right of way may be by successive actuations on that street within the protection interval timed by relay X, for a maximum interval timed by relay W after the first actuation on the latter street.

It is pointed out that if switches DI-D2 and KI-KZ, for instance, under the system of operation described under heading B above, arev kept closed continuously, then the right of way will normally shift periodically, and for predetermined intervals governed by the time relay W, between two of the streets A and B, in the absence of actuation on the other street C, but that upon actuation on street C in any one cycle a right of way period will be given to street C in its order within that cycle.

From the foregoing it will `be understood that a System and timer is provided by means of which the objects as specifically aforementioned, are achieved. It is obvious that with the arrangement of parts as described, a minimum of traic interruption will occur incident to the handling of the tramo flow in a manner such that danger of collision will be reduced to a minimum.

The right of way is maintained for a period adequate to permit an approaching vehicle to negotiate the intersection and in the event of no traflic awaiting right of way in one lane the apparatus does not unnecessarily accord right ofv way to that lane, but transfers the right of way to the lane awaiting the same. l

It will be understood that any number of changes and rearrangements of the parts might be resorted to without departing from the spirit of the invention as dened by the claims.

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

1. A traiiic control vsystem for more than two interfering traiiic lanes including signaling means to accord right-of-way over any one lane while interrupting right of way over the other lanes, vehicle actuated controls associated one with each of said lines, means including timing mechanism connected to said signalling means and vehicle actuated controls and having one operating cycle for said signalling means to sequentially accord and interrupt right of way to the succeeding vehicle lanes when activated, and means cooperating with the second named means for activating the latter responsive to actuation of the respective vehicle actuated controls to cause right of way to be accorded to the next succeeding vehicle lane in which a vehicle actuated control has been actuated, and means to maintain interruption of right of way through said signalling means in any intervening lane in which the vehicle actuated control has not been actuated.

2. A traiiic control system for more than two interfering traffic lanes including signaling means to accord right of way over any one lane while interrupting right of way over the other lanes, vehicle actuated controls associated one with each of said lanes, means including timing mechanism connected to said signalling means and vehicle actuated controls andY having an operating cycle for said signalling means to sequentially accord and interrupt right of way to the succeeding vehicle lanes responsive to actuation of the several vehicle actuated controls, and means forming a part of said timing mechanism to cause said accord of right of way to any one lane and interruption of right of way to the other lanes to continue for minimum periods of time and in response to actuations of the control associated with the lane currently having right of way.

3. A traiiic control system for more than two interfering traflic lanes including signaling means to accord right of way over any one of said lanes while interrupting right of way-over the other lanes', traiiic actuated means ln the lanes and operating means connected to both the signallingmeans and traffic actuated means and operating in response to functioning of the latter for causing the signalling means to shift right of way to that lane in which such traiiic actuated means has operated. l

4. A traffic control system for more than two interfering traiiic lanes including signalling means to accord right of way over any one of said lanes while interrupting right of way over the other lanes, trafc actuated means in the lanes, operating means connected to both the signalling means and trafc actuated means and operating in response to functioning of the latter for causing the signalling means t'o shift right of way to that lane in which such traffic actuated means has operated and timing means forming a part of said operating means for preventing any further transfer of right of` way indication for minimum periods of time.

5. A traffic control system for more than two interfering trailc lanes including signaling means to accord right of way over any one of said lanes while interrupting right of way over the other lanes, traiiic actuated means. in the lanes, operating means connected to both the signalling means and the tramo actuated means kand operating -in response to functioning of the latter for causing the signalling means to shift right of way to that lane in which such trafilc actuated means has operated, timing means for maintaining each right of way indication for at least a minimum period of time and means whereby said period may be extended by actuations of the trailic actuated means located in the lane which is being accorded right of way.

6. A traiiic control system for more than two interfering traffic lines including signaling means to accord right of way over any one of said lanes while interrupting right of way over the other lanes, traffic actuated means in the lanes, timing means connected to both the signalling means and the traffic actuated means for maintaining the displayed right of way indication for at least a minimum period of time, means forming a part of said timing means whereby said pe- -interrupting right-of-way to the other lanes,

riod may be extended by further actuations oi.'

` the tramo actuated means of the lane which is being accorded right of way, further means also forming a part of said timing means and operating in response to actuations of a traflic actuated means in another lane for limiting such period of right of way indication and means connected to said timing means for causing shifting of right of way indicationto such other lane upon the expiration of such period of right of way in dication.

7. A traiiic control system including, in oombination, a signalling means to be disposed adjacent the intersection of more than two mutually interfering traiiic lanes and to accord right of Way to traiic moving over one of said lanes While interrupting right of way to traic moving over the other lanes, a timer connected tosaid signalling means to operate the same, a trafiic actuated control for each of at least two of said lanes and connected to said timer, and means forming a part of said timer and acting in response to actuation of any one of said controls to cause said signalling means to transfer right of way in favor of the lane whose control has been actuated, l

8. A trailc control system including, in oombination, a signalling means to be disposed at the point of intersection of more than two trac lanes and to accord right of way to traffic moving over one of said lanes, while interrupting right of way to the other lanes, tramo actuated controls disposed in the lanes and in advance of such intersection, a cyclicV timer connected to said signalling means and having more than two operating positions in its cycle corresponding to said more than two traffic lanes andl adapted lwhen activated to .operate through such cycle to operate the signalling means to accord' right of way to the several lanes sequentially and adapted when not activated to remain in the operating position to which it was last activated, and means connecting said controls to said timer t0 activate the latter from one position to another in response to a vehicle actuating the former.

9. A tramc control system for more than two interfering tramo lanes including signalling means to accord right-of-way to one lane while interrupting right-of-way to the other lanesy switch means for each of said'lanes, timer means operating when said switch means are closed for two of said lanes to cause said signalling means to cyclically accord right-of-way alternately for predetermined periods to each of said two lanes, and means cooperating with said timing means when the switch means for a third lane is closed to cause the transfer of right-of- Way to said third lane for a predetermined period followed by the resumption of cyclic operation.

10. A tranc control system for more than two interfering traffic lanes including signalling means to accord right-of-way to one lane while interrupting right-of-way to the other lanes, traiiic actuatable means in one of said lanes, timing means operatingtto cause said signalling means to cyclically accord right-of-way successively for predetermined periods to each of said lanes. and means to interrupt the cyclic operation to give the right-of-Way to said one lane in response to actuation of said traffic actuatable means.

l11. A trafc control systemfor more than two interfering tralc' lanes including signalling means to accord right-of-way to one lane While traffic actuatablemeans in each of said lanes, timing meansv operating to cause said signalling means to cyclically accord.` right-of-way successively for predetermined periods to each oi' said lanes in the absence oi actuation, and'means to interrupt the cyclic operation to give the right-of-way to one of said lanes substantially forthwith in response to actuation in said one lane.

12. A trarlic control system for more than two interfering tralic lanes including signalling means to accord right-of-way to one lane while interrupting vright-of-way to the other lanes, traic actuatable means in each lane, means to transfer right-of-way from one lane to another lane in responseto actuation of the trac actuatable means inthe latter lane, and means maintaining interruption of right-o-way to any intervening lane during such transfer, in absence of actuation on said intervening lane.

13. A traffic control system for more than two interfering trac lanes including signalling means to accord right-of-way to one lane while interrupting right-of-way to the other lanes, traidc .actuatable means in each lane, control means including timing means to operate said signalling means to accord right-of-way successively for predetermined periods to each of the said lanes in a predetermined order in response to actuation `of all of the traic actuatable means, and said control means also including means responsive to non-actuation of any one of saidk traiiic actuatable means to operate said signalling means to maintain interruption of right of way inand to omit accord of right of way to the lane of the non-actuated trafllc actuatable means. p

14. vA traffic control system for more than two interfering traic lanes, including go and stop signals for each lane, traiilc actuatable means for each lane, and a controller comprisselector means in response to actuation of said traffic actuatable means on a lane having a "stop signal displayed, means causing said selector means to stop when operating the group of switching means corresponding to the said lane in which actuation occurred, to cause the go signal to be displayed and the stop signal to be extinguished on the latter lane, While stop signals are displayed on the other lanes, and timing means to maintain said selector means in said stopped condition for a predetermined minimum period.

l5. A traffic control system for more than two interfering trailic lanes, including go and stop signals for each lane, traiic actuatable means for each lane, and a controller comprising groups of switching means for each` lane, selector means for sequentially operating said groups of switching means in predetermined order when activated, means maintaining stop signals on all lanes on which actuation has not occurred, while the selector means is sequentially operating said groups of switching means, means activating said selector means in response to actuation of a trairlc actuatable device on a lane having a stop signal, means causing said selector means to stop when operating the group of switching means corresponding to the said lane ,in which actuation occurred, to cause the in sai minimum period.

164 A traflic control system including, in combination, a signalling means to .be disposed at the intersection of more than two mutually interfering traffic lanes, and to accord right of way to trailc moving over one of said lanes while' interrupting right of way to traffic moving over the other lanes, a timer connected to said signailing means to operate the same, a trafilo actuated control' for one of said lanes and connected to said timer, and means forming a part of said timer and acting in response to actuation of said traino actuated control to cause said signalling means to transferA right of way in favor of the laneof said traffic actuated control.

1'7. A trafc control system for more than two mutually interfering traffic lanes including signailing means to accord right of way to one lane whileinterrupting right of way to the other lanes, a control means including "timing means and connected to said signalling means to cause said signal-ling means to normally, cyclically accord right of way successively for predetermined periods to each of a plurality of said lanes, trafiic actuatable means associated with one of said lanes to which the right of Way is not normally cyclically accorded, and means cooperating with said control means when the saidtramc actuatable means is operated to cause the transfer of right'of way to the" lane of said tranic actuatable' means for a predetermined minimum period followed by resumption of normal cyclic operation.

18. A trairic control system forlmorethan two mutually interfering traffic lanes including signalling means to accord right of way to one lane while interrupting right of way to the other lanes, a .control means including timing means and connected to said signalling means to cause said signalling means to normally, cyclically accord right of way successively for predetermined periods to each .of a plurality of said lanes, trafnc actuatable means associated with one of said lanes to which the right'ofjway is not normally cyclically accorded, and means cooperating with .said control means when the said traflic actuatable means is operated to cause the transfer of right of way to the lane of said trailic actuatable means for a predetermined minimum period followed by resumption of normal cyclic operation, and further means forming a part of said control means and functioning in response to actuation of said traffic actuatable means during said predetermined minimum lperiod to cause the extensionv of right of way beyond said minimum.

19. Atrafiic control' system for more than two mutually interfering traffic lanesincluding signalling means to accord right of way to one lane while interrupting right of .way to the other lanes, a control means including timing means and connected to said signalling means to cause `said signalling means to normally, cyclically accord right of way successively for predetermined periods to each of a plurality of said lanes, trafc actuatable means associated with one of said lanes to which the right of way is not normally cyclically accorded, andmeans cooperating with said control means when the said trafllc actuatable means is operated to cause the transfer of right of way to the lane of said traino actuatable means for a predetermined minimum period followed by resumption of normal cyclic operation, and further means forming a part of said control means and functioning in response to actuation of said traffic actuatable means during said predetermined minimum period to cause the exmutually interfering traiiic lanes including sigy nailing means comprising means to accord and means to interrupt right of way for each of the lanes. `traffic actuatable means in one lane, control means including timing means functioning when the said traine actuatable means -is actuated while the .right of way is interrupted in the said one lane, to cause the transfer of right of way to the said one lane, and means to retain the'right of way in the said one lane for a predetermined minimum period before transfer to another lane canvbe effected. y

21. A traino control system for more than two mutually interfering trafic lanes including signalling means comprising lmeans to accord and means to interrupt right of way` for each of the lanes` traflic actuatable means in one lane, control means including timing means functioning when the said traflc actuatable means is actuated while the right of way is interrupted in the said one lane` to cause the transfer of right of way to the said one lane, and means to retain theright of wayin the said one lane for a predetermined minimum period before transfer to another lane can be effected, and further means functioning upon actuation of said traflic actuatable means during said predetermined minimum period to cause'the extension of rightof `Way beyond said minimum, and further means to limit to a predetermined maximum the exten- Vsion of right of way by continued or successive actuations.

22. A traiic control system for a street intersection including a pair of signal circuits, one circuit including a "stop signal yand the other circuit including a go signal, a source of power therefor, a switch means movable through a cycle for alternately connecting said circuits to said source of power, means for' moving said switch means at a selected speed, means operable by a unit of traic for initiating the operation of said moving means, and means actuated by said lastnamed means for regulating said moving means to vary the speed of movement of said switch means, said last named means being responsive to successive actuations of'said traffic-actuated means by successive units of trailc.

23. A traine control system for the intersection of a highway and at least one street, and having the usual stop and golights for the intersection, comprising switch mechanism for energizing said lights, and means in the highway operable by a vehicle seeking to make a left turn- 25. A tramc control system for an intersection of a plurality of interfering lanes including stop and go signal circuits for the lanes, a source of power therefor, a switch mechanism movable through a cycle for alternately connecting said circuits to said source of power to successively accord right of way to the lanes, means operable by a unit of traine for initiating the operation of said mechanism, and means operable upon actuation by another traflc unit to stop movement of said switch mechanism whereby the time length of said cycle is increased.

26. A traflic control system for more than two mutually interfering traine lanes including signalling means to accord right of way to any one lane while interrupting right of Way Vto the other lanes, a control means including timing means and a cyclic switching mechanism having a, plurality of switching positions in its cycle and normally having operative connection with said signalling means to cause the signalling means to accord right of way cyclically and successively for time periods determined by said timing means to each of a plurality of said lanes and to-maintain interruption of right oi Way continuously in another of said lanes, traflic actuatable means associated with said another lane, anv electromagnetic device connected with said cyclic -mechanism and adapted when` operatedvto change the operative connection between said mechanism and said signalling means to accordright` of way to said another lane and interrupt right of way in the remaining said lanes for a predetermined minimum time period only in a certainy position in said cycle and said electromagnetic device having a connection with said traiilc` actuatable means to be initially so operated by -actuation of the'latter means, and means includinterfering tramo lanes including signalling means for the several lanes to accord right of way over any one of said'lanes while interrupting right `ci way over the other lanes, trame actuated means for the several lanes, cyclic switching mechanism having more than two switching positions through whichy it is adapted to be operated cyclically to provide potential periods of operation of the signalling means for right `of Way to the several lanes in sequence, electromagnetic devices individual to the several lanes `and connected respectively to the respective tramo actuated means for such lanes and to the cyclic mechanism to be operated'individually from .an unoperated condition to an operated condition byactuation of the respective traiiic actuated means to operate in such operated condition of the respective devices the respective right of way signalling means at the respective switching positions in `cooperation with said mechanism to-convert the potential operating period for anyof said Ilanes to an actual right of way operatingl period responsive to such actuation and to operate in such unoperated condition of the respective `devices the right of way interrupting signalling means for the respective lanes, and a time controlled driving ated condition of the electromagnetic device associated with said another switching position and to maintain said switching mechanism in the latter switching position for a minimum time' ,v for such actualright ofway period, and holding circuit means for the respective electromagnetic devices connected withsaid switching mechanism to hold any such devicein operated condition after operation by the tramo actuated means and into the switching position with which such device is associated to provide such actual right of way period and then to release such device.

HENRY` A. HAUGH, J B.

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