SE1650235A1

SE1650235A1 - Method and control unit in a mass transit system

Info

Publication number: SE1650235A1
Application number: SE1650235A
Authority: SE
Inventors: Ibrahim Mohammed; Kjelldal Therese
Original assignee: Scania Cv Ab
Priority date: 2016-02-24
Filing date: 2016-02-24
Publication date: 2017-08-25
Also published as: SE542558C2; DE102017001293A1; BR102017002490A2

Abstract

Method (400) and control unit (210) for maintaining a time difference (At) between a preceding vehicle (100-1) and a subsequent vehicle (100-2) within a time interval (Un -Wx) when arriving at a terminal (130). The method (400) comprises: estimating (401) an expected stop time (t) of the preceding vehicle (100-1) when arriving at the terminal (130); estimating. (402) an arrival time (t) of the subsequent vehicle (100-2) for arriving at the terminal (130); calculating (403) an expected time difference (At) by subtracting the estimated (402) arrival time (t2) of the subsequent vehicle (100-2) from the estimated (401) stop time (t) of the preceding vehicle (100-1); determining (404) a recommended velocity for the subsequent vehicle (100-2), in order to keep the expected time difference (At) between the vehicles (100-1, 100-2) within the time interval (Un -Wx); and outputting (405) the recommended velocity to the driver of the subsequent vehicle (100-2).(Publ. Fig. 1)

Description

METHOD AND CONTROL UNIT IN A MASS TRANSIT SYSTEM TECHNICAL FIELD This document discloses a control unit and a method. More particularly, a method and acontrol unit is provided, for maintaining a time difference between a preceding vehicle and asubsequent vehicle, both comprised in a mass transit system, within a time interval when arriving at a terminal.

BACKGROUND An emerging technology is to drive vehicles such as e.g. busses, in groups of coordinatedvehicles, or vehicle trains. This technology is sometimes referred to as Bus Rapid Transit(BRT). BRT is a bus-based mass transit system, which may be regarded upon as a "surfacesubway", which aims at combining the capacity and speed of a subway with the flexibility,lower cost and simplicity of a bus system. ln some other concepts, the groups of coordinated vehicles may be starting individually fromdifferent suburbans, join in a common vehicle train when arriving at the city centre and thendrive jointly similar to tram wagons through the city centre, thereby providing high transpor-tation capacity within the city centre. The group of coordinated vehicles may then split upand continue to different end destinations. Thereby a high capacity transportation system is provided, which is flexible and adaptable to time varying demands.

Such bus-based mass transit system typically uses one driving lane, similar to a tram line orsubway, continuously or at moments of increased transportation demands, such as e.g. un-der rush hours. Often, these vehicles do not follow a time table, instead they run as often aspossible (e.g. as frequent as a couple of minutes between each vehicle). ldeally, from a passenger perspective, it would be desired that the vehicles of the masstransit system are equally distributed in time, rather than being driven in a concentrated groupof vehicles, followed by a long gap to the subsequent vehicle/ group of vehicles. Firstly, forreducing the average waiting time and transportation time for the individual passenger, sec-ondly for increasing the transportation comfort of the passengers, as most passengers enterthe firstly arriving vehicle in a group of sequentially arriving vehicles, which thus becomesovercrowded while the subsequently following vehicles may be sparsely populated.

A possible solution to the above described scenario may be to let the vehicles change places.However, this is usually not possible when the vehicles are running on rails, are following an electric line or drives in a dedicated traffic lane.

Thirdly, an even distribution of vehicles would make it possible to reduce the number of op-erating vehicles without prolonging the average waiting time of the passengers.

Further, the vehicles running on the same traffic route need sometimes to brake to a haltwhen the vehicle in front is loading/ unloading passengers at the terminal. ln case the dis-tance between the vehicles is short, such braking may be sudden and sharp.

Braking and/ or harsh acceleration are uncomfortable or even dangerous for passengers,perhaps in particular for standing passengers, disabled passengers, children, passengers inwheelchair, baby carriage, etc.

Further, a driving pattern comprising sudden braking and harsh acceleration also leads to increased fuel consumption in comparison with a smooth driving pattern. ln addition, different vehicles in the mass transit system may have different characteristicsand capacity in terms of engine power, weight, brakes etc., which makes it difficult to keep aconstant distance between the vehicles.

Also in case all the vehicles in the mass transit system are identical, having the same enginepower and braking capacity, there may be a different amount of passengers on the differentvehicles, which gives different weight to the vehicles. Further, a vehicle having standing pas-sengers, or passengers in wheelchair, baby carriage etc., may not be able to brake and/ oraccelerate as aggressively as an empty vehicle, or a vehicle with only seated and/ or beltedpassengers. lt appears that further development is required for reaching practical implementation of ve-hicle groups.

SUMMARY lt is therefore an object of this invention to solve at least some of the above problems andimprove driving in a group of coordinated vehicles.

According to a first aspect of the invention, this objective is achieved by a method in a controlunit. The method aims at maintaining a time difference between a preceding vehicle and asubsequent vehicle, both comprised in a mass transit system, within a time interval whenarriving at a terminal. The method comprises estimating an expected stop time of the pre-ceding vehicle when arriving at the terminal. Further the method comprises estimating an arrival time of the subsequent vehicle for arriving at the terminal. ln addition, the method alsocomprises calculating an expected time difference by subtracting the estimated arrival timeof the subsequent vehicle from the estimated expected stop time of the preceding vehicle.Furthermore, the method also comprises determining a recommended velocity for the sub-sequent vehicle, in order to keep the expected time difference between the vehicles withinthe time interval. The method also comprises outputting the determined recommended ve-locity to the driver of the subsequent vehicle.

According to a second aspect of the invention, this objective is achieved by a control unit.The control unit is configured for maintaining a time difference between a preceding vehicleand a subsequent vehicle comprised in a mass transit system within a time interval whenarriving to a terminal. The control unit is configured to estimate an expected stop time of thepreceding vehicle when arriving at the terminal. Further, the control unit is configured to es-timate an arrival time of the subsequent vehicle for arriving at the terminal. The control unitis in addition configured to calculate a future time difference by and subtracting the estimatedarrival time of the subsequent vehicle from the estimated expected stop time of the precedingvehicle. Furthermore, the control unit is configured to determine a recommended velocity forthe subsequent vehicle, in order to keep the future time difference between the vehicleswithin the time interval. The control unit is also configured to generate control signals foroutputting the determined recommended velocity to the driver of the subsequent vehicle via an output unit.

Thanks to the described aspects, by estimating a time difference between the vehicles driv-ing on a route based on predictions of stop time at the terminal for the preceding vehicle,and prediction of arrival time of the subsequent vehicle, a recommended velocity of the sub-sequent vehicle may be computed and presented to the driver of the subsequent vehicle. ltis thereby avoided that vehicles populating a traffic route are congested in a platoon. lnstead,the vehicles are distributed evenly along the route, leading to minimised or at least reducedexpected waiting times for the passengers. Thereby also the actual transportation time (in-cluding waiting time) is reduced, and a more effective mass transportation system isachieved. Thereby, the number of vehicles populating a certain route at a certain time maybe reduced, leading to radical cost savings, besides environmental benefits. ln addition, pas-sage comfort and safety is improved by reducing the risk of overcrowded passenger com-partments.

Other advantages and additional novel features will become apparent from the subsequentdetailed description.

FIGURES Embodiments of the invention will now be described in further detail with reference to theaccompanying figures, in which: Figure 1A illustrates an embodiment of a group of coordinated vehicles, driving on aroute; Figure 1B illustrates an embodiment of a group of coordinated vehicles, driving on aroute; Figure 2A illustrates a vehicle interior according to an embodiment; Figure 2B illustrates a vehicle interior and a vehicle external structure according to anembodiment; Figure 3A illustrates a group of coordinated vehicles and a minimum distance betweenthem; Figure 3B illustrates a group of coordinated vehicles and a maximum distance betweenthem; Figure 4 is a flow chart illustrating an embodiment of the method; Figure 5 is an illustration depicting a system according to an embodiment.

DETAILED DESCRIPTION Embodiments of the invention described herein are defined as a control unit and a methodin a control unit, which may be put into practice in the embodiments described below. Theseembodiments may, however, be exemplified and realised in many different forms and arenot to be limited to the examples set forth herein; rather, these illustrative examples of em-bodiments are provided so that this disclosure will be thorough and complete.

Still other objects and features may become apparent from the following detailed description,considered in conjunction with the accompanying drawings. lt is to be understood, however,that the drawings are designed solely for purposes of illustration and not as a definition ofthe limits of the herein disclosed embodiments, for which reference is to be made to theappended claims. Further, the drawings are not necessarily drawn to scale and, unless oth-en/vise indicated, they are merely intended to conceptually illustrate the structures and pro-cedures described herein.

Figure 1A illustrates a scenario wherein a number of vehicles 100-1, 100-2, driving in adriving direction 105 along a route 120, with an inter-vehicular time difference At. The vehi-cles 100-1, 100-2 are coordinated and organised in a group of coordinated vehicles 100-1,100-2, comprised in a mass transit system 110. A preceding vehicle 100-1 is stopping at aterminal 130. Within a certain time period, corresponding to the inter-vehicular time differ-ence At, the subsequent vehicle 100-2 arrives at the terminal 130.

The vehicle group may be described as a chain of coordinated, inter-communicating vehicles100-1, 100-2 travelling at given inter-vehicular time difference At and velocity. The inter-ve-hicular time difference At may be the same between all vehicles 100-1, 100-2 of the masstransit system 110 driving at the same route 120, in some embodiments; or rather, the inter-vehicular time difference At may be kept within the same time interval tmin -tmah ln other embodiments, the inter-vehicular time difference At may be kept within different timeintervals tmin -tmah e.g. when different time intervals tmin -tmax are applied at different times ofthe day, different days of the week, on particular holidays, etc.

Thus the inter-vehicular time difference At may be e.g. some minutes in some embodiments.lt is thereby possible to serve the passengers at the terminal 130 with vehicles 100-1, 100-2arriving at the terminal 130 at an evenly distributed periodicity.

The vehicles 100-1, 100-2 may comprise e.g. a multi-passenger vehicle such as a bus, acoach, a tram, a subway, a train, a trolley bus, a cable railway or any similar vehicle or othermeans of conveyance such as a truck or a car etc. The vehicles 100-1, 100-2 in the masstransit system 110 may comprise vehicles 100-1, 100-2 of the same, or different types indifferent embodiments.

Any, some or all of the vehicles 100-1, 100-2 may be driver controlled or driverless autono-mously controlled vehicles in different embodiments. However, for enhanced clarity, the ve-hicles 100-1, 100-2 are subsequently described as having a driver.

The illustrated embodiment with two vehicles 100-1, 100-2 comprised in the mass transitsystem 110 and a vehicle route 120 comprising only one terminal 130 is merely a non- limit-ing example. The mass transit system 1 10 and vehicle route 120 may comprise any arbitrarynumber of vehicles 100-1, 100-2 and/ or terminals 130.

The vehicles 100-1, 100-2 in the mass transit system 110 are coordinated via wireless sig-nals. Such wireless signal may comprise, or at least be inspired by wireless communicationtechnology such as Wi-Fi, Wireless Local Area Network (WLAN), Ultra Mobile Broadband(Ul\/IB), Bluetooth (BT), Radio-Frequency Identification (RFID), optical communication suchas Infrared Data Association (lrDA) or infrared transmission to name but a few possible ex- amples of wireless communications in some embodiments.

The communication may alternatively be made over a wireless interface comprising, or at least being inspired by radio access technologies such as e.g. 3GPP LTE, LTE-Advanced,E-UTRAN, UMTS, GSM, GSM/ EDGE, WCDMA, Time Division Multiple Access (TDMA) net-works, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, Worldwide lnteroperability for Micro-wave Access (WiMax), or Ultra Mobile Broadband (UMB), High Speed Packet Access(HSPA) Evolved Universal Terrestrial Radio Access (E-UTRA), Universal Terrestrial RadioAccess (UTRA), GSM EDGE Radio Access Network (GERAN), 3GPP2 CDMA technologies,e.g., CDMA2000 1x RTT and High Rate Packet Data (HRPD), or similar, just to mention some few options, via a wireless communication network. ln some embodiments, the communication between vehicles 100-1, 100-2 in the mass transitsystem 110 may be performed via vehicle-to-vehicle (V2V) communication, e.g. based onDedicated Short-Range Communications (DSRC) devices. DSRC works in 5.9 GHz bandwith bandwidth of 75 MHz and approximate range of 1000 m in some embodiments.

The wireless communication may be made according to any IEEE standard for wireless ve-hicular communication like e.g. a special mode of operation of IEEE 802.11 for vehicularnetworks called Wireless Access in Vehicular Environments (WAVE). IEEE 802.11p is anextension to 802.11 Wireless LAN medium access layer (MAC) and physical layer (PHY)specification. ln some embodiments, when the vehicles 100-1, 100-2 in the mass transit system 110 are coordinated and are communicating.

Figure 1B illustrates a scenario of the mass transit system 110, similar to or identical withthe one illustrated in Figure 1A, but seen from another perspective.

The inter-vehicular time difference At between the coordinated vehicles 100-1, 100-2 arekept within a predetermined or configurable time interval tmin -tmah when arriving at the termi-nal 130. This is performed by using various information resources in order to calculate theexpected stop time for the preceding vehicle 100-1 at the terminal 130. Such informationresources may comprise e.g. historical information based on collected statistics associatedwith time, date, day of the month, month of the year etc., at the terminal 130; and/ or weatherconditions (more people may use public transportation when it rains). Further, such infor-mation resources may comprise passenger counting at the preceding vehicle 100-1; pas-senger counting at the terminal 130; vehicle weight; presence of passengers with specialneeds such as disabled passengers, children, senior passengers, etc., knowledge aboutpopular events in the surroundings of the terminal 130 (soccer game and other sport events, musical concert, etc.) and/ or a weighted combination of some or all of the above parameters.

Further, geographical position and speed information of the subsequent vehicle 100-2 onthat traffic route/ line 120 (or statistical information concerning the time required for the sub-sequent vehicle 100-2 to arrive at the terminal 130) may be used for estimating an arrivaltime at the terminal 130 within the predetermined or configurable time interval tmm -tmaß Basedon this computation, a recommended individual speed limit (or speed interval) for the subse-quent vehicle 100-2 may be calculated and outputted to the driver (in case a driver is present)or set at the cruise control of the subsequent vehicle 100-2 (e.g. in case of autonomousvehicle). Thereby, vehicles 100-1, 100-2 will arrive at that terminal 130 with regular intervals. lt is thereby assured that the vehicles 100-1, 100-2 of the mass transit system 110 are evenlydistributed over the route 120. Thereby, the waiting time of passengers at the terminals 130is minimised or at least reduced, as clustering of vehicles 100-1, 100-2 driving on the sameroute 120 is avoided. By distributing the vehicles 100-1, 100-2 evenly, less number of vehi-cles 100-1, 100-2 may be required on a certain route 120 at a certain time period. Therebyfuel and money is saved. Also, pollution is reduced, in case of fuel propelled vehicles 100-1,100-2. Further, more evenly distributed vehicles 100-1, 100-2 along the route 120 will en-hance passenger comfort on-board, as the likelihood of overcrowding of some vehicles 100-1, 100-2 will be reduced. By avoiding overcrowding and standing passengers, the vehicles100-1, 100-2 will be able to drive faster and accelerate/ decelerate more fast, leading toshorter transportation time for the passengers. Further, by avoiding that the subsequent ve-hicle 100-2 speed up in order to reach the terminal 130 as fast as possible, when the timedifference At is very low, i.e. below the lower time interval limit tmin, fuel/ energy is saved atthe subsequent vehicle 100-2. By avoiding harsh acceleration/ deceleration, not only fuel issaved, but also brake lining. Further, the risk of on board accidents with passengers falling over is reduced.

Figure 2A illustrates an example of a scenario as it may be perceived by the driver of thesubsequent vehicle 100-2, i.e. the second vehicle 100-2 in the group of coordinated vehicles100-1, 100-2 of the mass transit system 110. The driver view of e.g. the preceding vehicle100-1 may be identical or similar in some embodiments.

The vehicle 100-1 may comprise a communication device 200 and a control unit 210 whereincomputations and calculations of driving parameters of the vehicles 100-1, 100-2 in the groupmay be performed. The control unit 210 for maintaining the time difference At between thepreceding vehicle 100-1 and the subsequent vehicle 100-2 comprised in the mass transit system 110 within a time interval tmin -tmax when arriving to the terminal 130.

Further, the vehicle 100-1 may comprise a database 240, comprising various statistical dataand the like such as e.g. stored statistics associated with the terminal 130 at current timeand date. These stored statistics may comprise e.g. average stop time at the following ter-minal 130, depending on date, time, day of the week, time of the year; weather conditions CTC.

An expected stop time tis of the preceding vehicle 100-1 when arriving at the terminal 130may then be estimated based on e.g. such statistical data. lt may thus firstly be determinedwhich terminal 130 the preceding vehicle 100-1 is situated at, time/ date information may beextracted from on-board timepiece and an average statistical stop time tis may be extractedfrom the database 140, using the determined terminal 130 and time/ date data as input val- UBS.

However, the expected stop time tis of the preceding vehicle 100-1 may also, or in addition,be estimated based on passenger counting on the preceding vehicle 100-1. Such passengercounting may be made e.g. by a sensor in the preceding vehicle 100-1, counting each personentering/ leaving the vehicle 100-1; by seat pressure sensors in the preceding vehicle 100-1; by counting the number of sold tickets; by having one or more cameras and a face recog-nition software in the preceding vehicle 100-1, or similar passenger counting method. Thisdata may be transmitted from the preceding vehicle 100-1, e.g. while standing at the terminal130, or upon request. This data may be received via wireless communication on the com-munication device 200.

The number of passengers in the preceding vehicle 100-1 may be estimated by weightingthe vehicle 100-1 by on-board pressure sensors and assuming an average weight per pas- senger, in some embodiments.

The expected stop time tis may then be determined by a mapping between the number ofpassengers and an expected stop time tis, e.g. stored in the database 140.

Further, the expected stop time tis of the preceding vehicle 100-1 may be estimated basedon passenger counting at the terminal 130, e.g. by one or more sensors arranged at theterminal 130, or cameras in combination with an image recognition software. Such passen-ger counting at the terminal 130 may be combined with the on-board passenger counting onthe preceding vehicle 100-1 in some embodiments. This data may be received via wireless communication on the communication device 200. ln other embodiments, the expected stop time tis of the preceding vehicle 100-1 may beestimated further based on knowledge of public events in the close surroundings of the ter-minal 130, such as soccer games or other sport events, music concerts, festivals, etc. Such information may be received from a news service by a service provider, or similar. ln same alternative embodiments, the expected stop time tis of the preceding vehicle 100-1may be estimated by the driver on the preceding vehicle 100-1, based on a visual inspectionof the amount and type of passengers on board, and an estimation based on personal expe- nence.

The expected stop time tis of the preceding vehicle 100-1 may further, according to someembodiments, be a pre-set value, such as e.g. 1 minute, 3 minutes, etc. (arbitrary examples). ln some embodiments, e.g. in case the preceding vehicle 100-1 does not have any passen-ger counting ability or communication ability, the expected stop time tis of the precedingvehicle 100-1 may be estimated further based on the number of passengers in the subse-quent vehicle 100-2 (assuming that the preceding vehicle 100-1 will have about the same passenger population). ln some additional embodiments, some or all of the above described methods for estimatingstop time tis of the preceding vehicle 100-1 may be combined by giving different weight todifferent methods, e.g. 60% reliance on statistical values and 40% reliance on passenger counüng.

Furthermore, an expected arrival time tgs of the subsequent vehicle 100-2 for arriving at theterminal 130 may be computed, e.g. based on statistical information stored in the database240 concerning the route 120 and the distance to the terminal 130.

The distance to the terminal 130 may be calculated by knowing the route 120 and the positionof the terminal 130, e.g. by storing/ extracting it in the database 240; and by determining thegeographical position of the subsequent vehicle 100-2.

The geographical position of the subsequent vehicle 100-2 may be determined by the posi-tioning unit in the vehicle 100-2, which may be based on a satellite navigation system suchas the Navigation Signal Timing and Ranging (Navstar) Global Positioning System (GPS),Differential GPS (DGPS), Galileo, GLONASS, or the like.

The geographical position of the positioning unit, (and thereby also of the vehicle 100-2) may be made continuously with a certain predetermined or configurable time intervals according to various embodiments.

The geographical position of the subsequent vehicle 100-2 may aiternatively be determined,e.g. by having transponders positioned at known positions around the route 120 and a sensorin the vehicle 100-2, for recognising the transponders and thereby determining the position;by detecting and recognising WiFi networks (WiFi networks along the route 120 may bemapped with certain respective geographical positions in the database 240); by receiving aBluetooth beaconing signal, associated with a geographical position, or other signal signa-ture of wireless signals. The position may aiternatively be entered by the driver.

By knowing the route 120, the position of the terminal 130 and the current position of thesubsequent vehicle 100-2, the expected arrival time tga may be computed based on the dis-tance between the subsequent vehicle 100-2 and the terminal 130 along the route 120, andknowledge about the allowed driving speed of the route 120, or statistical average drivingspeed of the route 120, or an estimated driving speed of the route 120 based on the numberof passengers, or weight of the subsequent vehicle 100-2, in different embodiments.

An expected time difference At may then be calculated by the control unit 210 by subtractingthe estimated arrival time tga of the subsequent vehicle 100-2 from the estimated expectedstop time tls of the preceding vehicle 100-1. Based there upon, a recommended velocity forthe subsequent vehicle 100-2 may be determined in order to keep the expected time differ-ence At between the vehicles 100-1, 100-2 within the time interval tmin -tmaß A limitation maybe made in some embodiments, so that the recommended velocity never exceeds localspeed limits along the route 120.

This recommended velocity may then be outputted to the driver of the vehicle 100-2, e.g. onan output unit 220, 230, such as e.g. a display 220, a loudspeaker 230, or a haptic device.Other output units 220, 230, or presentational devices may be utilised instead, or as a com-plement such as e.g. a display on the dashboard, a head up display, a projector projectinginside or outside the vehicle 100-2, intelligent glasses of the driver, etc. ln the illustrated embodiment, the control unit 210 and the database 240 are situated onboard the vehicle 100-1. However, in other embodiments, the control unit 210 and/ or thedatabase 240 may be situated in a vehicle external structure 320, as illustrated in Figure 2B.

The vehicle external structure 320 in the alternative embodiment illustrated in Figure 2B comprises a transceiver 330, configured for wireless communication with the communication 11 device 200 in the vehicle 200-1, 200-2. Further the vehicle external structure 320 also maycomprise a control unit 210 and a database 240, configured for performing the same or sim-ilar functionalities as previously described in conjunction with the presentation and descrip-tion of Figure 2A.

Figure 3A illustrates a minimum time distance tm". between the vehicles 100-1, 100-2 com-prised in the mass transit system 110. The minimum time distance tmln may be the lower limitin a time interval tmm -tmax wherein it may be endeavoured to keep the time difference Atbetween the preceding vehicle 100-1 and the subsequent vehicle 100-2 when arriving at theterminal 130.

The minimum time distance tmin may be predetermined or configurable e.g. to some minutes,or some seconds, in order to achieve an appropriate even distribution of vehicles 100-1, 100-2 along the route 120. By avoiding to set the minimum time distance tmln to a too short timevalue, i.e. by setting it long enough for allowing the driver of the subsequent vehicle 100-2 tobrake the vehicle 100-2 in a relaxed and controlled manner, giving the driver enough time toavoid panic braking. Thereby energy is saved, brake lining is saved and the risk of injuredpassengers of the subsequent vehicle 100-2.

Figure 3B illustrates a maximum time distance tmax between the vehicles 100-1, 100-2 com-prised in the mass transit system 110. The maximum time distance tmax may be the upperlimit in the time interval tmm -tmax wherein it may be endeavoured to keep the time differenceAt between the preceding vehicle 100-1 and the subsequent vehicle 100-2 when arriving atthe terminal 130.

The maximum time distance tmax may be predetermined or configurable e.g. to some minutes,in order to achieve an appropriate even distribution of vehicles 100-1, 100-2 along the route120.

Figure 4 illustrates an example of a method 400 according to an embodiment. The flow chartin Figure 4 shows the method 400 in a control unit 210. The control unit 210 may be situatedin a vehicle 100-1, comprised in a group of coordinated vehicles 100-1, 100-2 in a formation,i.e. one vehicle after another in a sequence, in a mass transit system 110. ln other embodi-ments, the control unit 210 may be situated in a vehicle external structure 320.

The method aims at maintaining a time difference At between a preceding vehicle 100-1 anda subsequent vehicle 100-2 comprised in the mass transit system 110 within a time interval tmin -tmax when arriving at a terminal 130. 12 The vehicles 100-1, 100-2 in the coordinated group may be any arbitrary kind of means forconveyance. However, in some particular embodiments, the vehicles 100-1, 100-2 may bevehicles for public transportation of passengers such as busses, trains, trams, monorails, elevators or similar. ln order to correctly be able to keep the formation of the group and maintain the time differ-ence At between the vehicles 100-1, 100-2, the method 400 may comprise a number of steps401-406. Step 406 may be performed only in some optional embodiments. Further, the de-scribed steps 401-406 may be performed in a somewhat different chronological order thanthe numbering suggests. The method 400 may comprise the subsequent steps: Step 401 comprises estimating an expected stop time tis of the preceding vehicle 100-1when it arrives at the terminal 130.

The expected stop time tis of the preceding vehicle 100-1 at the terminal 130 may be esti-mated based on stored statistics associated with the terminal 130 at current time and date;passenger counting at the preceding vehicle 100-1; passenger counting at the terminal 130;weight of the preceding vehicle 100-1; or in a combination thereof, or with other similar meth- ods in various embodiments.

Alternatively, in some embodiments, the number of passengers entering the respective ve-hicles 100-1, 100-2 may be counted by a sensor at the respective vehicle entrance (or alter-natively by keeping track of the number of sold tickets). The number of standing passengersmay be estimated by knowing the number of seats and making a comparison with the num-ber of entered passengers (making an assumption that most passengers prefer to sit, if it ispossible), at each vehicle 100-1, 100-2. Alternatively, seat sensors may be situated in theseats of the vehicles 100-1, 100-2, and the number of seated passengers may be subtractedfrom the number of entered passengers.

The estimation may also, or alternatively be based on detection of wheel chairs and/ or babycarriages in any of the vehicles 100-1, 100-2, in some embodiments, as such passengers may elongate the expected stop time tis.

Step 402 comprises estimating an arrival time tgs of the subsequent vehicle 100-2 for arrivingat the terminal 130, where the preceding vehicle 100-1 is situated momentarily.

The arrival time tgs of the subsequent vehicle 100-2 for arriving at the terminal 130 may be 13 estimated based on current geographical position of the subsequent vehicle 100-2;knowledge of the vehicle route between the current position and the terminal 130; statisticaltravel time associated with the vehicle route between the current position and the terminal130 at current time and date; passenger counting at the subsequent vehicle 100-2; weightof the subsequent vehicle 100-2; presence of standing passengers in the vehicle 100-2; ora combination thereof.

Further, belt sensors at the seats may be used for detecting if the seated passengers arebelted. ln case all passengers are seated and belted, the velocity, acceleration and retarda-tion of the subsequent vehicle 100-2 may be increased in some embodiments.

Thus, in case all passengers are seated and belted, an increase of maximum velocity/ ac-celeration/ retardation may be allowed. ln case all passengers are seated but not belted, amore modest velocity/ acceleration/ retardation may be applied while sudden velocity in-crease (as well as sudden braking) may be avoided when there are standing passengers inthe subsequent vehicle 100-2.

Step 403 comprises calculating an expected time difference At by subtracting the estimated402 arrival time tga of the subsequent vehicle 100-2 from the estimated 401 expected stoptime tis of the preceding vehicle 100-1, i.e. At = tis - tga.

Step 404 comprises determining a recommended velocity for the subsequent vehicle 100-2,in order to keep the expected time difference At between the vehicles 100-1, 100-2 within the time interval tmm -tmah when arriving at the terminal 130.

The recommended velocity for the subsequent vehicle 100-2 may take into account also themaximum speed limits of the route, as well as the passenger situation on board the vehicle100-2, as previously discussed.

Step 405 comprises outputting the determined 404 recommended velocity to the driver ofthe subsequent vehicle 100-2. The recommended velocity may be outputted on an outputunit 220, 230 such as a display 220, a loudspeaker 230, a projector, a haptic device, or other presentational device etc., in various embodiments. ln some embodiments, e.g. when there is no driver present in the subsequent vehicle 100-2, the cruise control of the vehicle 100-2 may be set to the recommended velocity. 14 Step 406, which only may be performed in some alternative embodiments, comprises re-stricting performance of the subsequent vehicle 100-2 when the velocity of the subsequentvehicle 100-2 exceeds the determined 404 recommended velocity with a threshold velocity.

Such restriction may be made by applying and allowing a velocity limitation and/ or an accel-eration limitation of the subsequent vehicle 100-2. ln case the subsequent vehicle 100-2 isstanding on another terminal, the vehicle 100-2 may be prohibited from starting until a certaintime period has passed, in some embodiments.

Figure 5 illustrates an embodiment of a mass transit system 110. The system 110 is config-ured for maintaining a time difference At between a preceding vehicle 100-1 and a subse-quent vehicle 100-2 comprised in the mass transit system 110 within a time interval tmin -tmaxwhen arriving to a terminal 130. The system 1 10 comprises a transceiver 200 for transmitting/receiving vehicle related information. Further, the system 110 comprises a control unit 210.

The control unit 210 aims at maintaining the time difference At between the preceding vehicle100-1 and the subsequent vehicle 100-2 comprised in the mass transit system 110 withinthe time interval tmin -tmah when arriving to the terminal 130, according to at least some of thepreviously described steps 401-406 of the method 400 described above and illustrated inFigure 4.

The control unit 210 is configured to estimate an expected stop time tis of the precedingvehicle 100-1 when arriving at the terminal 130. Further, the control unit 210 is configured toestimate an arrival time tga of the subsequent vehicle 100-2 for arriving at the terminal 130.The control unit 210 is in addition configured to calculate a future time difference At by andsubtracting the estimated arrival time tga of the subsequent vehicle 100-2 from the estimatedexpected stop time t1s of the preceding vehicle 100-1. ln further addition, the control unit 210is configured to determine a recommended velocity for the subsequent vehicle 100-2, in or-der to keep the future time difference At between the vehicles 100-1, 100-2 within the timeinterval tmm -tmaß The control unit 210 is also configured to generate control signals for out-putting the determined recommended velocity to the driver of the subsequent vehicle 100-2via an output unit 220, 230.

According to some embodiments, the control unit 210 may be configured to restrict perfor-mance of the subsequent vehicle 100-2 when the velocity of the subsequent vehicle 100-2exceeds the determined recommended velocity with a threshold velocity. Further, the controlunit 210 may be alternatively configured to estimate the expected stop time tis of the preced-ing vehicle 100-1 at the terminal 130 based on stored statistics associated with the terminal 130 at current time and date; passenger counting at the preceding vehicle 100-1; passengercounting at the terminal 130; weight of the preceding vehicle 100-1 ; or a combination thereof.

Further, in some embodiments, the control unit 210 may be configured to estimate the arrivaltime tga of the subsequent vehicle 100-2 for arriving at the terminal 130 based on currentgeographical position of the subsequent vehicle 100-2; knowledge of the vehicle route be-tween the current position and the terminal 130; statistical travel time associated with thevehicle route between the current position and the terminal 130 at current time and date;passenger counting at the subsequent vehicle 100-2; weight of the subsequent vehicle 100-2; presence of standing passengers in the vehicle 100-2; or a combination thereof.

The control unit 210 may comprise a processor 520 configured for performing various calcu-lations and computations in order to perform the method 400, according to the previouslydescribed steps 401 -406.

Such processor 520 may comprise one or more instances of a processing circuit, i.e. a Cen-tral Processing Unit (CPU), a processing unit, an Application Specific Integrated Circuit(ASIC), a microprocessor, or other processing logic that may interpret and execute instruc-tions. The herein utilised expression "processor" may thus represent a processing circuitrycomprising a plurality of processing circuits, such as, e.g., any, some or all of the ones enu-merated above.

Furthermore, the control unit 210 may comprise a memory 525 in some embodiments. Theoptional memory 525 may comprise a physical device utilised to store data or programs, i.e.,sequences of instructions, on a temporary or permanent basis. According to some embodi-ments, the memory 525 may comprise integrated circuits comprising silicon-based transis-tors. The memory 525 may comprise e.g. a memory card, a flash memory, a USB memory,a hard disc, or another similar volatile or non-volatile storage unit for storing data such ase.g. ROIVI (Read-Only Memory), PROIVI (Programmable Read-Only Memory), EPROIVI(Erasable PROIVI), EEPROIVI (Electrically Erasable PROIVI), etc. in different embodiments.

The control unit 210 may further comprise an input/ output unit 510, forming a communicationinterface with the transceiver 200 for transmitting/ receiving vehicle related information.

The previously described steps 401-406 to be performed in the control unit 210 may be im-plemented through the one or more processors 520 within the control unit 210, together withcomputer program product for performing at least some of the functions of the steps 401-406. Thus a computer program product, comprising instructions for performing the steps 401- 16 406 in the control unit 210 may perform the method 400 comprising at least some of thesteps 401-406 for maintaining the time difference At between the preceding vehicle 100-1and the subsequent vehicle 100-2 comprised in the mass transit system 110 within the timeinterval tmin -tmax when arriving to the terminal 130, when the computer program is loaded intothe one or more processors 520 of the control unit 210. The described steps 401-406 thusmay be performed by a computer algorithm, a machine executable code, a non-transitorycomputer-readable medium, or a software instructions programmed into a suitable program- mable logic such as the processor 520 in the control unit 210.

The computer program product mentioned above may be provided for instance in the formof a data carrier carrying computer program code for performing at least some of the step401 -406 according to some embodiments when being loaded into the one or more proces-sors 520 of the control unit 210. The data carrier may be, e.g., a hard disk, a CD ROIVI disc,a memory stick, an optical storage device, a magnetic storage device or any other appropri-ate medium such as a disk or tape that may hold machine readable data in a non-transitorymanner. The computer program product may furthermore be provided as computer programcode on a server and downloaded to the control unit 210 remotely, e.g., over an Internet or an intranet connection.

Further, some embodiments may comprise a vehicle 100-1, 100-2 of the mass transit system110, comprising the control unit 210, as described above.

Further, some embodiments may comprise a vehicle external structure 320, comprising thecontrol unit 210, as described above.

The terminology used in the description of the embodiments as illustrated in the accompa-nying drawings is not intended to be limiting of the described method 400, control unit 210;computer program, mass transit systemsystem 110, vehicle 100-1, 100-2 and/ or vehicleexternal structure 320. Various changes, substitutions and/ or alterations may be made, with-out departing from invention embodiments as defined by the appended claims.

As used herein, the term "and/ or" comprises any and all combinations of one or more of theassociated listed items. The term "or" as used herein, is to be interpreted as a mathematicalOR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless ex-pressly stated otherwise. ln addition, the singular forms "a", "an" and "the" are to be inter-preted as "at least one", thus also possibly comprising a plurality of entities of the same kind,unless expressly stated othen/vise. lt will be further understood that the terms "includes", 17 "comprises", "including" and/ or "comprising", specifies the presence of stated features, ac-tions, integers, steps, operations, elements, and/ or components, but do not preclude thepresence or addition of one or more other features, actions, integers, steps, operations, ele-ments, components, and/ or groups thereof. A single unit such as e.g. a processor may fulfil5 the functions of several items recited in the claims. The mere fact that certain measures arerecited in mutually different dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage. A computer program may be stored/ distributed ona suitable medium, such as an optical storage medium or a solid-state medium suppliedtogether with or as part of other hardware, but may also be distributed in other forms such 10 as via Internet or other wired or wireless communication system.

Claims

1. A method (400) in a control unit (210) for maintaining a time difference (At) betweena preceding vehicle (100-1) and a subsequent vehicle (100-2) comprised in a mass transitsystem (110) within a time interval (tmin -tmax) when arriving at a terminal (130), wherein themethod (400) comprises: estimating (401) an expected stop time (tls) of the preceding vehicle (100-1) whenarriving at the terminal (130); estimating (402) an arrival time (tga) of the subsequent vehicle (100-2) for arriving atthe terminal (130); calculating (403) an expected time difference (At) by subtracting the estimated (402)arrival time (tga) of the subsequent vehicle (100-2) from the estimated (401) expected stoptime (tis) of the preceding vehicle (100-1); determining (404) a recommended velocity for the subsequent vehicle (100-2), inorder to keep the expected time difference (At) between the vehicles (100-1, 100-2) withinthe time interval (tmin -tmax); and outputting (405) the determined (404) recommended velocity to the driver of thesubsequent vehicle (100-2).

2. The method (400) according to claim 1, further comprising: restricting (406) performance of the subsequent vehicle (100-2) when the velocityof the subsequent vehicle (100-2) exceeds the determined (404) recommended velocity witha threshold velocity.

3. The method (400) according to any of claim 1 or claim 2, wherein the expected stoptime (tls) of the preceding vehicle (100-1) at the terminal (130) is estimated (401) based onstored statistics associated with the terminal (130) at current time and date; passenger count-ing at the preceding vehicle (100-1); passenger counting at the terminal (130); weight of thepreceding vehicle (100-1); or a combination thereof.

4. The method (400) according to any of claims 1-3 wherein the arrival time (tga) of thesubsequent vehicle (100-2) for arriving at the terminal (130) is estimated based on currentgeographical position of the subsequent vehicle (100-2); knowledge of the vehicle route be-tween the current position and the terminal (130); statistical travel time associated with thevehicle route between the current position and the terminal (130) at current time and date;passenger counting at the subsequent vehicle (100-2); weight of the subsequent vehicle(100-2); presence of standing passengers in the vehicle (100-2); or a combination thereof. 19

5. A control unit (210) for maintaining a time difference (At) between a preceding ve-hicle (100-1) and a subsequent vehicle (100-2) comprised in a mass transit system (110)within a time interval (tmin -tmax) when arriving to a terminal (130), wherein the control unit(210) is configured to: estimate an expected stop time (t1s) of the preceding vehicle (100-1) when arrivingat the terminal (130); estimate an arrival time (tga) of the subsequent vehicle (100-2) for arriving at theterminal (130); calculate a future time difference (At) by and subtracting the estimated arrival time(t2a) of the subsequent vehicle (100-2) from the estimated expected stop time (tis) of thepreceding vehicle (100-1); determine a recommended velocity for the subsequent vehicle (100-2), in order tokeep the future time difference (At) between the vehicles (100-1, 100-2) within the time in-terval (tmin -tmax); and generate control signals for outputting the determined recommended velocity to thedriver of the subsequent vehicle (100-2) via an output unit (220, 230).

6. The control unit (210) according to claim 5, further configured to:restrict performance of the subsequent vehicle (100-2) when the velocity of the sub-sequent vehicle (100-2) exceeds the determined recommended velocity with a threshold ve- locity.

7. The control unit (210) according to any of claim 5 or claim 6, further configured toestimate the expected stop time (t1s) of the preceding vehicle (100-1) at the terminal (130)based on stored statistics associated with the terminal (130) at current time and date; pas-senger counting at the preceding vehicle (100-1); passenger counting at the terminal (130);weight of the preceding vehicle (100-1); or a combination thereof.

8. The control unit (210) according to any of claims 5-7, further configured to estimatethe arrival time (tga) of the subsequent vehicle (100-2) for arriving at the terminal (130) basedon current geographical position of the subsequent vehicle (100-2); knowledge of the vehicleroute between the current position and the terminal (130); statistical travel time associatedwith the vehicle route between the current position and the terminal (130) at current time anddate; passenger counting at the subsequent vehicle (100-2); weight of the subsequent vehi-cle (100-2); presence of standing passengers in the vehicle (100-2); or a combinationthereof.

9. A mass transit system (110) comprising a preceding vehicle (100-1) and a subse-quent vehicle (100-2) with a time difference (At) in-between them maintained within a timeinterval (tmin -tmax) when arriving to a terminal (130), wherein the system (110) further com- pnses:a control unit (210) according to any of claims 5-8; anda transceiver (200) for communication of vehicle related information.

10. A computer program comprising program code for performing a method (400) ac- cording to any of claims 1-4, when the computer program is executed in a control unit (210)according to any of claims 5-8.

11. (210) according to any of claims 5-8. A vehicle (100-1, 100-2) of a mass transit system (110), comprising a control unit

12. of claims 5-8. A vehicle external structure (320) comprising a control unit (210) according to any