Patent Publication Number: US-2022217237-A1

Title: Vehicle remote assistance system, remote assistance apparatus, remote assistance method, and remote assistance program

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation application of International Application No. PCT/JP2020/030483, filed on Aug. 7, 2020, which claims priority to Japanese Patent Application No. 2019-180417, filed on Sep. 30, 2019. The contents of these applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a vehicle remote assistance technology that performs assignment of an operator to a call to provide assistance by an operator when a vehicle calls an operator. 
     Related Art 
     A service in which an operator at an assistance center remotely provides assistance to a vehicle when the vehicle requires assistance has been proposed. In this service, for example, regarding an autonomous driving vehicle, in a case in which the vehicle is unable to move based on determination by the vehicle and is stranded, a case in which the vehicle is in an accident, a case in which the vehicle is actively requesting assistance from an operator, and the like, the vehicle makes an operator call to the assistance center. 
     SUMMARY 
     One aspect of the present disclosure provides a vehicle remote assistance system that includes a plurality of vehicles and a remote assistance apparatus. Each of the plurality of vehicles includes a calling unit that transmits a call to the remote assistance apparatus. The remote assistance apparatus includes an assigning unit that schedules the calls that are transmitted from the plurality of vehicles and assigning the calls to any of a plurality of operators. The calling unit transmits a cancelation of the call to the remote assistance apparatus when a reason for the call is resolved after the call is made. The assigning unit cancels scheduling of the call that corresponds to the cancelation that is transmitted from the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a block diagram illustrating a configuration of a remote assistance system according to an embodiment; 
         FIG. 2  is a diagram illustrating a relationship between a minimum waiting period, a maximum waiting period, and priority levels according to the embodiment; 
         FIG. 3  is a diagram illustrating a queue of a plurality of calls according to the embodiment; 
         FIG. 4  is a diagram illustrating an example in which two types of queues are used; 
         FIG. 5  is a diagram illustrating an example in which three types of queues are used; 
         FIG. 6  is a diagram for explaining a cancel function according to the embodiment; 
         FIG. 7  is a flowchart illustrating an allocation process of a call to a queue according to the embodiment; and 
         FIG. 8  is a flowchart illustrating an assignment process by an assigning unit according to the embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The following embodiments relate to a vehicle remote assistance system that performs assignment of an operator to a call to provide assistance by an operator when a vehicle calls an operator, a remote assistance apparatus, a remote assistance method, and a remote assistance program. 
     A service in which an operator at an assistance center remotely provides assistance to a vehicle when the vehicle requires assistance has been proposed (for example, refer to Japanese Patent No. 5550671). In this service, for example, regarding an autonomous driving vehicle, in a case in which the vehicle is unable to move based on determination by the vehicle and is stranded, a case in which the vehicle is in an accident, a case in which the vehicle is actively requesting assistance from an operator, and the like, the vehicle makes an operator call to the assistance center. 
     When operator calls are simultaneously made from a plurality of vehicles and the operator at the assistance center is unable to respond the operator calls, the vehicles are required to wait until the operator is able to respond. Therefore, in the assistance center, when calls are received from a plurality of vehicles, the calls are scheduled and assigned to the operator in an appropriate order. 
     However, in scheduling of a plurality of calls that are received from a plurality of vehicles, when a number of calls exceed a number of operators, an operator cannot necessarily be immediately assigned when a call is received. A plurality of calls are placed in a queue and a waiting period occurs. In conventional vehicle remote assistance, if a reason for a call is resolved in a vehicle during the waiting period, assistance from an operator is no longer needed by the time the call is assigned to an operator. Even calls such as this in which assistance is no longer needed are required to be assigned to an operator and handled. Therefore, load that is placed on the operator increases. 
     It is thus desired to reduce load that is placed on an operator by suppressing unnecessary calls. 
     A first exemplary embodiment provides a vehicle remote assistance system that includes a plurality of vehicles and a remote assistance apparatus. Each of the plurality of vehicles includes a calling unit that transmits a call to the remote assistance apparatus. The remote assistance apparatus includes an assigning unit that schedules the calls that are transmitted from the plurality of vehicles and assigns the calls to any of a plurality of operators. The calling unit transmits a cancelation of the call to the remote assistance apparatus when a reason for the call is resolved after the call is made. The assigning unit cancels scheduling of the call that corresponds to the cancelation that is transmitted from the vehicle. The remote assistance apparatus schedules the call based on a priority level that becomes higher in accompaniment with a waiting period of the call. 
     The priority level becomes higher in order of: a case in which the waiting period is less than a minimum waiting period; a case in which the waiting period exceeds the minimum waiting period and falls below a maximum waiting period; and a case in which the waiting period exceeds the maximum waiting period. The assigning unit does not assign the call to the operator in response to the waiting period being less than the minimum waiting period. 
     A second exemplary embodiment provides a remote assistance apparatus that configures a vehicle remote assistance system together with a plurality of vehicles. The remote assistance apparatus includes: a receiving unit that receives calls that are transmitted from a calling unit provided in each of the plurality of vehicles; and an assigning unit that schedules the calls that are received by the receiving unit based on a priority level that becomes higher in accompaniment with a waiting period of the call, and assigns the calls to any of a plurality of operators. The calling unit transmits a cancelation of the call to the remote assistance apparatus when a reason for the call is resolved after the call is made. The assigning unit cancels scheduling of the call that corresponds to the cancelation that is transmitted from the vehicle. 
     The priority level becomes higher in order of: a case in which the waiting period is less than a minimum waiting period; a case in which the waiting period exceeds the minimum waiting period and falls below a maximum waiting period; and a case in which the waiting period exceeds the maximum waiting period. The assigning unit does not assign the call to the operator in response to the waiting period being less than the minimum waiting period. 
     The third exemplary embodiment provides a remote assistance method for assigning an operator to remotely assist a plurality of vehicles. The remote assistance method includes: receiving calls that are transmitted from the plurality of vehicles; scheduling the calls that are received based on a priority level that becomes higher in accompaniment with a waiting period of the call, and assigning the calls to any of a plurality of operators; receiving a cancelation of the call; and canceling scheduling of the call that corresponds to the cancelation based on reception of the cancelation. The priority level becomes higher in order of: a case in which the waiting period is less than a minimum waiting period; a case in which the waiting period exceeds the minimum waiting period and falls below a maximum waiting period; and a case in which the waiting period exceeds the maximum waiting period. The call is not assigned to the operator, in response to the waiting period being less than the minimum waiting period. 
     The fourth exemplary embodiment provides a non-transitory computer-readable storage medium storing therein a remote assistance program for assigning an operator to remotely assist a plurality of vehicles, the remote assistance program causing an information processing apparatus including a receiving unit to implement: scheduling a call that is received from a vehicle by the receiving unit based on a priority level that becomes higher in accompaniment with a waiting period of the call, and assigning the call to any of a plurality of operators; and canceling, based on a cancelation of the call that is received from the vehicle by the receiving unit, scheduling of the call that corresponds to the cancelation. The priority level becomes higher in order of a case in which the waiting period is less than a minimum waiting period; a case in which the waiting period exceeds the minimum waiting period and falls below a maximum waiting period; and a case in which the waiting period exceeds the maximum waiting period. The call is not assigned to the operator, in response to the waiting period being less than the minimum waiting period. 
     An embodiment of the present disclosure will hereinafter be described with reference to the drawings. Here, the embodiment described below is an example of implementation of the present disclosure and does not limit the present disclosure to the specific configurations described below. In implementation of the present disclosure, specific configurations according to the embodiment may be used as appropriate. 
       FIG. 1  is a block diagram of a configuration of a vehicle remote assistance system according to the embodiment. A vehicle remote assistance system  100  includes an autonomous driving vehicle (referred to, hereafter, as an “AD vehicle”)  10 , a remote assistance apparatus  20 , a plurality of operator terminals  30 , an autonomous driving (AD) center apparatus  40 , and a police/emergency apparatus  50 . 
       FIG. 1  shows only a single AD vehicle  10 . However, a plurality of AD vehicles  10  can simultaneously use a single remote assistance apparatus  20 . The AD vehicle  10  and the remote assistance apparatus  20  perform communication over a communication network. The AD vehicle  10  can be wirelessly connected to the communication network. The AD vehicle  10  may be connected to the communication network using a mobile phone network. Alternatively, the AD vehicle  10  may be connected to the communication network through a public wireless local area network (LAN). 
     The remote assistance apparatus  20  is an apparatus that is operated by a provider of a vehicle remote assistance service. The remote assistance apparatus  20  is communicably connected to the plurality of operator terminals  30 . In an assistance center, a plurality of operators are on standby. Each operator is assigned a single operator terminal  30 . 
     Each AD vehicle  10  is capable of making an operator call to the remote assistance apparatus  20 . When the operator call is received from the AD vehicle  10 , the remote assistance apparatus  20  assigns an operator to the call. Specifically, when the call is received, the remote assistance apparatus  20  schedules the call and performs operator assignment. As a result, communication between the AD vehicle  10  that has made the call and the operator terminal  30  of the assigned operator is established. The remote assistance apparatus  20  establishes the communication between the AD vehicle  10  that has made the call and the operator terminal  30  that is assigned the call. 
     According to the present embodiment, the remote assistance apparatus  20  also provides a function as a relay that relays communication between the AD vehicle  10  and the operator terminal  30 . However, this relay function may be provided by an apparatus other than the remote assistance apparatus  20 . 
     In addition, the AD center apparatus  40  and the police/emergency apparatus  50  can be connected to the remote assistance apparatus  20  through the communication network. In a manner similar to the AD vehicle  10 , the AD center apparatus  40  and the police/emergency apparatus  50  are also capable of making an operator call to the remote assistance apparatus  20 . 
     When the operator terminal  30  is connected to any of the AD vehicles  10  and when the connection is broken, the operator terminal  30  gives notification thereof to the remote assistance apparatus  20 . As a result, an assigning unit  22  of the remote assistance apparatus  20  can ascertain which of the plurality of operator terminals  30  are in operation, which are on standby, that is, which operators are available, and how many operators are available. 
     The AD vehicle  10  includes an operating unit  11 , a sensing unit  13 , a calling unit  12 , an emergency level determining unit  14 , and a transmitting/receiving unit  15 . The operating unit  11  is a switch, a touch panel, or the like that is operated by a passenger of the AD vehicle  10  to make an operator call. The operating unit  11  outputs, to the calling unit  12 , an operation signal that is based on an operation that is received. The sensing unit  13  is a sensor that detects a physical quantity of light, acceleration, radio waves, sound, rotation frequency, or the like. The sensor that detects light also includes an image sensor that configures a camera. The sensor that detects radio waves also includes a reception antenna of a millimeter-wave radar. 
     A plurality of sensors for detecting internal and external states of the AD vehicle  10  are provided in the AD vehicle  10  as the sensing unit  13 . A sensing result (presence/absence of a sensing target or a detection value) of each sensor is outputted to the calling unit  12 . The calling unit  12  determines a state in which the AD vehicle  10  is placed based on the sensing results of the sensing unit  13 . The calling unit  12  may be a portion of an autonomous driving control unit that generates a command for each driving system for autonomous driving based on the sensing results. 
     As state determination, for example, the calling unit  12  may perform recognition, determination, calculation, and acknowledgment such as the following. Through recognition of an image of a vicinity of the AD vehicle  10  that is acquired by an image sensor, presence of an obstacle, another vehicle, a pedestrian, or the like in the vicinity of the AD vehicle  10  is recognized, and a size, a movement direction, a distance, and the like thereof are determined. 
     In addition, the calling unit  12  recognizes the presence of an obstacle or the like based on a detection result from the millimeter wave radar and determines the distance and the like thereof. Furthermore, the calling unit  12  calculates a speed of the AD vehicle  10  based on a detection value of a sensor that detects a rotation frequency of a wheel. In addition, the calling unit  12  acknowledges a collision of the AD vehicle  10  based on a detection value of an acceleration sensor. 
     The calling unit  12  determines whether an operator call is necessary based on the result of state determination. When determined that operator call is necessary, the calling unit  12  generates a call and outputs the call to the emergency level determining unit  14  and the transmitting/receiving unit  15 , together with information on a reason for the determination. 
     In addition, the calling unit  12  generates the call based also on the operating signal from the operating unit  11 . At this time, a call reason may be determined based on operation details of the operating unit  11 . Alternatively, the emergency level determining unit  14  may determine an emergency level based on the operation details of the operating unit  11 . 
     For example, in a case in which the AD vehicle  10  is provided with an emergency call button that is operated when the emergency level is high and an operator assistance button that is operated when the emergency level is low as the operating unit  11 , when the emergency call button is operated, the emergency level determining unit  14  may determine the emergency level to be “high.” When the operator assistance button is operated, the emergency level determining unit  14  may determine the emergency level to be “low.” Furthermore, when the operating unit  11  is a touch panel, the passenger may input or select the call reason. 
     For example, when the AD vehicle  10  remains stopped in a period that exceeds a predetermined threshold, the calling unit  12  may output the call together with the call reason that indicates that a stopping period exceeds the threshold. In addition, for example, when a traveling path of the AD vehicle  10  is blocked by a roadside parked vehicle and the AD vehicle  10  is required to cross a centerline to advance while avoiding the roadside parked vehicle, and safety when the centerline is crossed is determined to not be ensured, the calling unit  12  may output the call together with the call reason that indicates stranding as a result of a roadside parked vehicle. 
     Furthermore, for example, when the detection value of the acceleration sensor exceeds a predetermined threshold (such as 100 m/s 2 ), the calling unit  12  may determine that the AD vehicle  10  has collided (or has been collided with) and output the call together with the call reason that indicates that acceleration exceeds the threshold or a collision has occurred. 
     The emergency level determining unit  14  determines the emergency level of the call based on the state that is sensed by the sensing unit  13 . Specifically, the emergency level determining unit  14  determines the emergency level of the call based on the call reason that is determined by the calling unit  12  based on the state that is sensed by the sensing unit  13 . Therefore, the emergency level determining unit  14  includes an emergency level table that prescribes a relationship between all call reasons that may be determined by the calling unit  12  and the emergency levels thereof. 
     When a call request is received together with the call reason from the calling unit  12 , the emergency level determining unit  14  references the emergency level table and determines the emergency level that corresponds to the call reason. Here, the emergency level determining unit  14  may determine the emergency level by directly using the state that is sensed by the sensing unit  13 . For example, when the acceleration sensor detects acceleration that exceeds a predetermined threshold (such as 100 m/s 2 ), the emergency level determining unit  14  may immediately determine that the emergency level is the highest. 
     The transmitting/receiving unit  15  transmits the operator call, together with the emergency level that is determined by the emergency level determining unit  14 , to the remote assistance apparatus  20 . For example, the transmitting/receiving unit  15  may be a wireless communication module for connecting to a mobile phone network of a predetermined carrier. The operator call includes a vehicle identifier (ID) for identifying the AD vehicle  10 , a call ID for identifying the call of the AD vehicle  10 , and the call reason. 
     The remote assistance apparatus  20  includes a transmitting/receiving unit  21  and an assigning unit  22 . The transmitting/receiving unit  21  is a communication interface for connecting to a communication network. The assigning unit  22  is actualized by a general-purpose processor (such as a central processing unit [CPU]) running a remote assistance program according to the present embodiment while using a memory, a storage medium, a dedicated processor, and the like as required. The remote assistance program may be provided to a computer over a wired or wireless communication network. Alternatively, the remote assistance program may be stored in a computer-readable non-transitory storage medium and provided to the computer by the computer reading the remote assistance program from the storage medium. 
     The assigning unit  22  schedules a plurality of calls that are transmitted from a plurality of AD vehicles  10  based on priority levels that become higher in accompaniment with the waiting period of the call, and assigns the calls to any of a plurality of operators. Here, the priority levels are divided into a plurality of levels based on a length of the waiting period. The priority level is “low” when the waiting period is less than a minimum waiting period. The priority level is “medium” when the waiting period exceeds the minimum waiting period and falls below a maximum waiting period. The priority level is “high” when the waiting period exceeds the maximum waiting period. The priority levels become higher in this order. 
       FIG. 2  is a diagram of a relationship between the minimum waiting period and the maximum waiting period, and the priority levels. As shown in  FIG. 2 , when an elapsed time from when the call is issued from the AD vehicle  10  (or reaches the remote assistance system  20 ), that is, the waiting period is equal to or greater than 0 seconds and equal to or less than a minimum waiting period LL, the priority level is “low.” The assigning unit  22  does not assign the call to an operator during this period. 
     When time elapses and the waiting period exceeds the minimum waiting period LL and falls below the maximum waiting period UL, the assigning unit  22  assigns the call to an operator in order of arrival when an occupancy rate of the operators of which there is a plurality is equal to or less than a predetermined threshold (such as 60%). 
     When time further elapses without an operator being assigned and the waiting period exceeds the maximum waiting period UL, the assigning unit  22  assigns the call to an available operator in order of arrival regardless of the occupancy rate of the operators. 
     According to the present embodiment, during the period in which the priority level is “low,” the assigning unit  22  does not assign an operator. Therefore, unnecessary calls are suppressed and operator occupancy and load can be suppressed. Here, instead of the foregoing, when the priority level is “low,” the assigning unit  22  may use a threshold (such as 30%) for the occupancy rate of the operators that is lower than that of the period in which the priority level is “medium,” and may assign an operator only when the occupancy rate is lower than this threshold. Unnecessary calls can be suppressed by this configuration as well. 
     In addition, according to the present embodiment, during the period in which the priority level is “high,” the assigning unit  22  forcibly assigns an operator when an available operator is present, regardless of the occupancy rate of the operators. In this manner, as a result of an operator being assigned to a call of which a predetermined amount of time (that is, the maximum waiting period UL) has elapsed, occurrence of a call to which an operator is not assigned no matter how much time passes can be prevented. 
       FIG. 3  is a diagram of a queue of a plurality of calls according to the embodiment. When calls are made from a plurality of AD vehicle  10 , the assigning unit  22  generates a queue  221  in which the calls are arrayed in order of arrival. In this queue  221 , the minimum waiting period LL is 30 seconds and the maximum wait time UL is 120 seconds. The assigning unit  22  determines whether a head call in the queue  221  satisfies a call condition. When the condition is satisfied, the assigning unit  22  assigns an operator. 
     That is, when the waiting period of the head call is equal to or less than the minimum waiting period LL, the assigning unit  22  determines that this call does not satisfy the condition. When the waiting period of the head call exceeds the minimum waiting period LL but does not reach the maximum waiting period UL, the assigning unit  22  determines that the condition is satisfied when the occupancy rate of the operators is equal to or less than a predetermined threshold, and determines that the condition is not satisfied when the occupancy rate is equal to or greater than the threshold. In addition, when the waiting period of the head call has already exceeded the maximum waiting period UL, the assigning unit  22  determines that the condition is satisfied. Here, when the waiting period exceeds the maximum waiting period UL, no operators may be available. In this case, the call remains placed at the head of the queue  221  without the assignment process being completed. 
     The assigning unit  22  may dynamically adjust the minimum waiting period LL and/or the maximum waiting period UL based on an occupancy state of the operators. That is, when the occupancy rate of the operators is low, the assigning unit  22  may adjust the minimum waiting period LL and/or the maximum waiting period UL to be shorter. Conversely, when the occupancy rate of the operators is high, the assigning unit  22  may adjust the minimum waiting period LL and/or the maximum waiting period UL to be longer. Here, such adjustment of the minimum waiting period LL and/or the maximum waiting period UL can be performed in examples in  FIG. 4  and  FIG. 5 , described below, as well. 
     When assignment of an operator to the head call is successful, the assigning unit  22  removes the call from the queue  221  and moves up the order of all calls that are waiting in the queue. 
     The assigning unit  22  according to the present embodiment has a plurality of types of queues that are applied based on the emergency level of the call.  FIG. 4  is a diagram of an example in which two types of queues according to the embodiment are used. As shown in  FIG. 4 , the assigning unit  22  has a plurality of queues of which the combinations of the minimum waiting period LL and the maximum waiting period UL differ. In the example in  FIG. 4 , a queue  222  in which the minimum waiting period LL is 10 seconds and the maximum waiting period UL is 30 seconds, and a queue  223  in which the minimum waiting period LL is 60 seconds and the maximum waiting period UL is 120 seconds are shown. 
     The assigning unit  22  selects any of the plurality of types of queues based on the emergency level that is transmitted from the AD vehicle  10  together with the operator call, and allocates the call to the selected queue. In the example in  FIG. 4 , the emergency level determining unit  14  selects either of “high” and “low” as the emergency level and provides the emergency level to the remote assistance apparatus  20  together with the call. The assigning unit  22  allocates a call that has a “high” emergency level to the queue  222  of which the minimum waiting period LL and the maximum waiting period UL are both relatively short periods, and allocates a call that has a “low” emergency level to the queue  223  of which the minimum waiting period LL and the maximum waiting period UL are both relatively long periods. 
     When a traveling state of the AD vehicle  10  is abnormal, the emergency level determining unit  14  determines that the emergency level is “high.” When the traveling state of the AD vehicle  10  is normal, the emergency level determining unit  14  determines that the emergency level is “low.” Specifically, in the example in  FIG. 4 , regarding calls of which the call reason is “blocked in” or “roadside parking,” the emergency level determining unit  14  recognizes that the traveling state is abnormal based on the call reason and determines that the emergency level is “high.” 
     In addition, when the call reason is “time out” (that is, when the stopping period exceeds a predetermined value), the emergency level determining unit  14  recognizes that the traveling state is normal based on the call reason and determines that the emergency level is “low.” The assigning unit  22  allocates the call of which the emergency level is “high” to the queue  222  of which the minimum waiting period LL and the maximum waiting period UL are both relatively short, and allocates the call of which the emergency level is “low” to the queue  223  of which the minimum waiting period LL and the maximum waiting period UL are both relatively long. 
       FIG. 5  is a diagram of an example in which three queues according to the embodiment are used. In this case, the assigning unit  22  has three types of queues of which the combinations of the minimum waiting period LL and the maximum waiting period UL differ. In addition, in this case, the emergency level determining unit  14  determines any of “highest,” “high,” and “low” as the emergency level. 
     A queue  224  is a queue for calls that have the “highest” emergency level. A queue  225  is a queue for calls that have a “high” emergency level. A queue  226  is a queue for calls that have a “low” emergency level. The assigning unit  22  allocates police request and emergency request calls from the police/emergency apparatus  50  to the queue  224  for calls that have the “highest” emergency level. In addition, the assigning unit  22  allocates calls from the AD center apparatus  40  to the queue  225  that has the “high” emergency level. 
     The minimum waiting period LL for the queue  224  that has the “highest” emergency level is 0 seconds and the maximum waiting period UL is 10 seconds. That is, in the queue  224 , a call of which the waiting period is less than 10 seconds is assigned to an operator if the operator occupancy is equal to or less than a predetermined threshold, and a call of which the wait time exceeds 10 seconds is forcibly assigned to an available operator. 
     In addition, although not shown as an example in  FIG. 5 , in cases in which the calling unit  12  of the AD vehicle  10  determines that an accident has occurred as well, a call is transmitted from the AD vehicle  10  to the remote assistance apparatus  20  with this occurrence of an accident as the call reason, and the emergency level determining unit  14  determines the emergency level of this call to be “highest” at this time. 
     In the example in  FIG. 5 , when the emergency level is “high,” in a manner similar to that in the example in  FIG. 4 , the call is allocated to the queue  225  of which the minimum waiting period LL and the maximum waiting period UL are relatively short. When the emergency level is “low,” in a manner similar to that in the example in  FIG. 4 , the call is allocated to the queue  226  of which the minimum waiting period LL and the maximum waiting period UL are relatively long. 
     When a plurality of queues are provided as shown in  FIG. 4  and  FIG. 5 , the assigning unit  22  assigns the calls in each queue in a following manner. That is, first, the assigning unit  22  acquires the head call of each queue and determines the priority levels thereof. When the priority level is not “high” (that is, when the priority level is “medium” or “low”), the call is assigned to an operator when the call condition is satisfied. The call is ignored when the call condition is not satisfied. 
     Regarding the head call of a queue, when the priority level thereof is “high” (that is, the priority level is the highest), the assigning unit  22  assigns the call to an available operator. When an available operator is not present, the assigning unit  22  waits until any of the operators becomes available and assigns the call to the operator. When assignment of an operator is completed for a certain call, a similar process is performed for the head call of the other queue when the priority level thereof is “high.” After processing of the head call of which the priority level is “high” is completed for all queues, processing of the head calls of the acquired queues is ended. 
     Next, a call cancelation function that is provided by the vehicle remote assistance system  100  according to the present embodiment will be described.  FIG. 6  is a diagram for explaining the cancelation function according to the embodiment. When the AD vehicle  10  is no longer able to travel as a result of a roadside parked vehicle P being present ahead, the AD vehicle  10  transmits a call to the remote assistance apparatus  20  (step S 61 ). This call is placed in a predetermined queue and awaits its turn for assignment. 
     During this time, the AD vehicle  10  waits in a state in which the AD vehicle  10  is unable to travel. However, when the roadside parked vehicle P starts to travel while the AD vehicle  10  is waiting (step S 62 ), the AD vehicle  10  is also able to travel because the obstacle ahead is no longer present. 
     In such cases, the AD vehicle  10  identifies the vehicle ID of the AD vehicle  10  and the corresponding call ID and transmits a call cancelation to the remote assistance apparatus  20  (step S 63 ). When the cancelation from the AD vehicle  10  is received, the remote assistance apparatus  20  removes the corresponding call from the queue and cancels the scheduling of this call (step S 64 ). 
     As a result of the call being canceled in this manner, a call that has become unnecessary during a wait can be prevented from being assigned to an operator. Therefore, operator assignment load on the assigning unit  22  and response load on the operator can be reduced. In addition, other calls that require response from operators can be more quickly assigned to the operators. 
     According to the present embodiment, in particular, because the minimum waiting period LL is set and a period until the minimum waiting period LL is reached is a period during which assignment to the operator is prohibited, calls that become unnecessary during this prohibited period can be expected to be canceled. 
       FIG. 7  is a flowchart of an allocation process of a call to a queue according to the embodiment. As shown in  FIG. 7 , first, a request source of the call is determined (step S 71 ). When the request source of the call is external (“external” at step S 71 ), that is, the AD center apparatus  40  or the police/emergency apparatus  50 , the call is allocated to the queue that has the “highest” emergency level (step S 72 ). 
     When the request source of the call is other than external (“other” at step S 71 ) that is, the AD vehicle  10 , first, whether the call reason of the call is an accident is determined (step S 73 ). When the call reason is an accident (“Yes” at step S 73 ), the call is allocated to the queue that has the “highest” emergency level (step S 72 ). 
     Meanwhile, when the call reason is not an accident (“No” at step S 73 ), the traveling state of the AD vehicle  10  is determined (step S 74 ). When the traveling state of the AD vehicle  10  is abnormal (“abnormal” at step S 74 ), the call is allocated to the queue that has the “high” emergency level (step S 75 ). When the traveling state of the AD vehicle  10  is normal (“normal” at step S 74 ), the call is allocated to the queue that has the “low” emergency level (step S 76 ). 
     As described above, the assigning unit  22  has a plurality of queues of which the combinations of the minimum waiting period LL and the maximum waiting period UL differ, and allocates the received call to any of the queues based on the emergency level thereof. Therefore, an operator can be more quickly assigned to a call that has a high emergency level. 
       FIG. 8  is a flowchart of an assignment process performed by the assigning unit according to the embodiment. First, the assigning unit  22  acquires the head call from each of the plurality of queues (step S 81 ). Next, the assigning unit  22  determines whether a call of which the waiting period exceeds the maximum waiting period UL is present among the head calls (step S 82 ). 
     When a call of which the waiting period exceeds the maximum waiting period UL is present (“Yes” at step S 82 ), the assigning unit  22  determines whether an operator is available (step S 83 ). As described above, information regarding whether the operator terminal  30  is in operation is sent from each operator terminal  30  to the remote assistance apparatus  20 . The assigning unit  22  can ascertain which of the operator terminals is not in operation. 
     When an operator is available (“Yes” at step S 83 ), the assigning unit  22  assigns the call of which the waiting period exceeds the maximum waiting period UL to the available operator (step S 84 ). When an operator is not available (“No” at step S 83 ), the assigning unit  22  monitors availability state of the operators until an operator becomes available (step S 83 ). When assignment of an operator to a certain call (step S 84 ) is completed, the assigning unit  22  determines whether another call of which the waiting period exceeds the maximum waiting period UL is present (step S 85 ). 
     When another call of which the waiting period exceeds the maximum waiting period UL is further present among the plurality of head calls acquired at step S 81  (“Yes” at step S 85 ), the assigning unit  22  returns to step S 83 . The assigning unit  22  determines whether an operator is available (step S 83 ) and assigns the operator to the call (step S 84 ). 
     When a call of which the waiting period exceeds the maximum waiting period UL is no longer present among the plurality of head calls acquired at step S 81  (“No” at step S 82 ), the assigning unit  22  returns to step S 81 . The assigning unit  22  acquires the head calls of the queues again (step S 81 ). 
     When a call of which the waiting period exceeds the maximum waiting period UL is not present among the acquired plurality of head calls (“No” at step S 82 ), the assigning unit  22  determines whether a call of which the waiting period exceeds the minimum waiting period is present among the calls (step S 86 ). When a call of which the waiting period exceeds the minimum waiting period LL is present (“Yes” at step S 86 ), the assigning unit  22  determines whether the occupancy rate of the operators is equal to or less than a predetermined threshold (step S 87 ). When the occupancy rate of the operators is equal to or less than the threshold (“Yes” at step S 87 ), the assigning unit  22  assigns an available operator to the call (step S 88 ). 
     When the occupancy rate of the operators is greater than the threshold (“No” at step S 87 ), the assigning unit  22  returns to step S 81  and acquires the head calls of the queues (step S 81 ). When an operator is assigned to a certain call (step S 88 ), the assigning unit  22  returns to step S 86 . The assigning unit  22  determines whether a call of which the waiting period exceeds the minimum waiting period LL is present among the plurality of head calls acquired at step S 81  (step S 86 ). 
     When a call of which the waiting period exceeds the minimum waiting period LL is not present among the head calls (“No” at step S 86 ), the assigning unit  22  returns to step S 81  and acquires the head calls of the queues again (step S 81 ). In addition, when the occupancy rate of the operators exceeds the threshold (“No” at step S 87 ) as well, the assigning unit  22  returns to step S 81  and acquires the head calls of the queues again (step S 81 ). 
     As described above, the assigning unit  22  acquires the head calls from the plurality of queues and performs assignment of the calls based on the priority levels. Therefore, calls with high priority levels can be preferentially assigned to operators. 
     Here, in the remote assistance apparatus  20 , when the assignment process is performed based on the flowchart in  FIG. 8 , a cancelation process is also performed in parallel. In the cancelation process, the remote assistance apparat  20  monitors whether a call cancelation is received from the AD vehicle  10  by the transmitting/receiving unit  21 . When the cancelation is received, the remote assistance apparatus  20  interrupts the assignment process and performs a process to remove the call that is related to the received cancelation from the queue. 
     An embodiment of the vehicle remote assistance system is described above. However, the vehicle remote assistance system is not limited to the above-described embodiment. Various modifications can be made to the above-described embodiment. Variation examples are described below. 
     According to the above-described embodiment, the emergency level determining unit  14  that determines the emergency level of the call is provided in each AD vehicle  10 . The determined emergency level is transmitted from the AD vehicle  10  to the remote assistance apparatus  20 , together with the call. However, instead, the emergency level determining unit may be provided in the remote assistance apparatus  20 . In this case, the AD vehicle  10  transmits the call reason to the remote assistance apparatus  20 , together with the call. The emergency level determining unit of the remote assistance apparatus  20  determines the emergency level of the call based on the call reason. 
     At this time, information on a vehicle type and a road being traveled may also be transmitted from the AD vehicle  10  to the remote assistance apparatus  20 , in addition to the call reason. The emergency level determining unit may determine the emergency level based on the information on the vehicle type and the traveling road as well. 
     Furthermore, according to the above-described embodiment, an example in which the AD vehicle  10 , that is, the autonomous driving vehicle, receives operator assistance is described. For example, as the AD vehicle  10 , a vehicle that has an autonomous driving level  4  may be suitable. However, the vehicle remote assistance system  100  can also be applied to a vehicle other than the autonomous driving vehicle and may be a system that remotely assists a vehicle that is driven by a driver.