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Dispatch (logistics)
Encyclopedia
Dispatch is a procedure for assigning employees (workers) or vehicles to customers. Industries that dispatch include taxicab
s, courier
s, emergency service
s, as well as home and commercial services such as maid
services, plumbing
, HVAC
, pest control
and electricians.
With vehicle dispatching, clients are matched to vehicles according to the order in which clients called and the proximity of vehicles to each client's pick-up location. Telephone operators take calls from clients, then either enter the client's information into a computer
or write it down and give it to a dispatcher
. In some cases, calls may be assigned a priority by the call-taker. Priority calls may jump the queue of pending calls. In the first scenario, a central computer then communicates with the mobile data terminal
located in each vehicle (see computer assisted dispatch); in the second, the dispatcher communicates with the driver of each vehicle via two-way radio.
With home or commercial service dispatching, customers usually schedule services in advance and the dispatching occurs the morning of the scheduled service. Depending on the type of service, workers are dispatched individually or in teams of 2 or more. Dispatchers have to coordinate worker availability, skill, travel time and availability of parts. The skills required of a dispatcher are greatly enhanced with the use of computer dispatching software (see computer aided call handling
).
In a tow truck example, the card might be labeled with the tow car's radio identifier, "Downtown 6" and may be labeled with the vehicle number or data about the capabilities of the specific tow car. It might give a weight capacity, show the unit as a flat bed or cradle snatcher, or mention the unit carries a can of Diesel fuel. The name of the staff on the car might be noted. At the start of a shift, the dispatcher would note the unit "available" and time stamp the card. At the assignment to a call, the call information would be written on the card and the card might be stamped at the moment the assignment is read to the tow car crew. The string of notes and time stamps allows dispatch staff to get a clear picture of the status of a small fleet.
Some systems use shelving with red and green lights and a switch at the back of the card slot. If the resource's card is pushed all the way into the card slot, the switch is actuated and an indicator lamp turns red. This identifies the tow car whose card occupies that slot as not available or assigned to a call. Leaving the card pulled partway out leaves the indicator green, showing the dispatcher that unit is available. Is anyone available? The lights are supposed to give the dispatch staff a snapshot of their resource situation.
A major flaw of this system is that cards are inside shelves and trying to look at an entire set of cards to evaluate the overall situation requires the dispatcher to pull out every card, one at a time, and read it. If two or more resources are sent to the same call, the dispatcher has a lot of writing to do.
In a tow truck example, the peg might be labeled with the tow car's radio identifier, "Downtown 6" and may be labeled with the vehicle number or data about the capabilities of the specific tow car. It might give a weight capacity, show the unit as a flat bed or cradle snatcher, or mention the unit carries a can of Diesel fuel. The name of the staff on the tow car might be noted. At the start of a shift, the dispatcher would note the unit "available" and time stamp a tag, then hang it on that unit's peg. At the assignment to a call, the call information would be written on another tag and the tag might be stamped at the moment the assignment is read to the tow car crew. The tag would then be hung on that unit's peg. The stack of tags allows dispatch staff to get a clear picture of the status of a small fleet.
Some systems use colored tags to show general categories of events such as "available". For example, each unit that is available might have the fact noted on an orange tag. Is anyone available? A glance at the pegboard shows anybody whose tag is "orange" is available. An repossession might use a yellow tag to identify a service call with a safety issue where the police should be called in the event the tow car crew doesn't check in by radio within five minutes. A blue tag might show a resource is taking a dinner or lunch break.
A major flaw of this system is that tags can easily be posted on the wrong peg, causing confusion. This can be countered by writing unit identifiers on every tag: a lot of work. In colored-tag systems, it's always possible to run out of certain colors of tags, messing up the system. If two or more resources are sent to the same call, the dispatcher has a lot of writing to do.
. The material has vertical stripes painted on it, making a column for each of several possible status conditions. The simplest system is two columns: available and unavailable. Magnetized icons can be used in place of Velcro. The icons can be colored or shaped to identify the type of unit or some other feature of the resource.
Each vehicle working the current shift has an icon placed in the column describing the unit's current status. A log book is used to track times, event details, and other information about calls for service. In a tow truck example, the icon might be labeled with the tow car's radio identifier, "Downtown 6". During a shift, the icon would be moved by the dispatcher into whatever column describes the resource's current condition. Alternatively, there could be columns for some other condition such as the names of move-up or standby points where resources are sent to backfill for busy tow cars.
A major flaw of this system is that icons can easily be misplaced or fall off of the status board. Magnetic objects can damage cathode ray tube displays if they get too close to the display face or housing.
operations in a few countries, a dispatcher
shares legal responsibility for a flight's safety with its pilot, and may delay, divert or cancel a flight if there is reason to do so. This checks and balances mechanism supposedly improves the safety of the dispatch system, although most countries do not use this system and there is no noticeable detriment to flight safety. A dispatcher typically must be licensed by the aviation authority of a country. The examination for the licence requires the candidate to demonstrate knowledge in meteorology and aviation comparable to that required to obtain an Airline Transport Pilot Licence.
. This allows for more flexible management of the workers out in the field as a job can be dispatched to multiple users to accept or reject the job. The benefits of a mobile system as it can then be integrated back into the other software systems used by an organization such as asset management, rostering, and other financial systems.
may encounter higher traffic around Christmas
. Work is not evenly distributed across time: in any dispatch system there are traditional peaks or busy hours in requests for service. Some workplace cultures will allow longer wait times than others.
Systems may use a voice procedure
to reduce talking time, allowing interaction with a larger dispatch fleet. Air traffic control and towing are two examples. The use of abbreviations or standard phrases can reduce the length of a transaction. Capacity may be reduced by relaxed voice procedure such as a delivery dispatcher giving a lengthy description of a customer complaint over the radio.
It's generally accepted that giving field units computers connected with the computer-aided dispatch, or another enterprise system used for dispatch, unloads voice two-way radio channels and increases capacity. Users research information on their terminal or laptop instead of calling in with a request that the dispatcher do it. One source suggests radio traffic drops by 30% when computers are available to mobile users.
One suggestion is that 100 to 150 mobiles is the maximum practical on one channel. Another suggests 60-70 units as a maximum. The difference in these two ranges probably reflects the wording. For example, 120 mobiles may mean radios: 60 units each containing a mobile radio and an officer with a walkie talkie. For dispatch systems like take-out food delivery, where life safety is not an issue, delays may be acceptable. Delays increase capacity.
Another possible measure of capacity is system push-to-talk presses. A 187-day study of four Contra Costa County, California
Sheriffs Department conventional two-way radio dispatch channels showed an average of around 2,500 push-to-talk presses per day. The count was within +/-350 a day across all four primary dispatch channels.
A method used for telephone traffic analysis may fit some circumstances. One evaluation looked at 1) peak of busy hour usage, 2) average hourly usage, 3) message length in seconds, 4) maximum delay or wait time desirable, and; 5) maximum percent of users being delayed. Traffic analysis
can be applied to radio or telephone communications.
Most office telephone systems have some facility for recording calling volumes, and incoming call timing. Dispatch centers use Automatic call distribution (ACD) groups which can be evaluated for metrics such as average wait time, abandoned calls, and calls per hour. These numeric data can be entered into spreadsheets for analysis of trends.
In dispatching, US emergency medical services literature suggests that telephone calls to a dispatching facility should be answered in the first few rings. One document suggests emergency calls to dispatch should result in busy signals once per 100 calls during the busiest hour. In business call centers, similar standards are suggested by consultants in order to provide an ideal customer experience and to outperform competing services. Sufficient staffing should be in place so that 90% of emergency calls are, "...answered within 10 seconds, or with no greater than three rings, during the average busy hour," according to one source. Tolerable wait times vary from one culture and region to another: some cultures expect immediate service; others will tolerate waits for some services.
One method for organizing assignments in a manual dispatch system is to use a zone map system. Consider a community with four fire stations and two ambulance service providers. A grid is overlaid on a community map. Saint Proximal Medical Center ambulance is identified by the notation P while Distal Volunteer Rescue Squad is noted with a D.
Each zone of the grid is identified with a progression of ambulance zones and fire stations. One zone might be labeled: DP241. This means fire station 2, then 4, then 1, then 3 would respond to a fire call occurring inside this zone. If fire stations 2, 4, and 1 were assigned to calls, Station 3 would be sent to this zone. Distal Volunteer Rescue Squad would be first-up for an ambulance call occurring inside zone DP241.
The predefined order is created by persons with expertise in the service being provided, local geography, traffic, and patterns in calls for service. In assigning resources to a zone, decision-makers may consider that responding units must drive around freeways, lakes, or terrain obstructions in order to reach a zone. Zone boundaries and designations will periodically change as communities grow or lessons are learned during day-to-day operations. Consider a zone with an irrigation canal defining one boundary. If a car crashes into the canal, which zone is it in?
Zone systems may include standby, move-up, or backfill points. For example, taxi drivers working in a certain zone in the evening hours may expect night club patrons to need a ride. Consider a standby point at Main Street and Railroad Avenue named N. Some fares will come from radio calls to dispatch. A taxi driver, Car 4, may go to predefined standby location N. In some dispatching systems, the driver will call the dispatcher and report they are available and located at standby point N. The dispatcher may respond by reporting the driver's position in the queue, "Car 4, second N." The first call in this district would go to the driver ahead of Car 4. Car 4 would be assigned the second call.
If automatic vehicle location
is available, it would display service vehicle locations on a map. The closest unit would be interpreted by the dispatcher looking at vehicle locations projected on the map.
Taxicab
A taxicab, also taxi or cab, is a type of vehicle for hire with a driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of their choice...
s, courier
Courier
A courier is a person or a company who delivers messages, packages, and mail. Couriers are distinguished from ordinary mail services by features such as speed, security, tracking, signature, specialization and individualization of express services, and swift delivery times, which are optional for...
s, emergency service
Emergency service
Emergency services are organizations which ensure public safety and health by addressing different emergencies. Some agencies exist solely for addressing certain types of emergencies whilst others deal with ad hoc emergencies as part of their normal responsibilities...
s, as well as home and commercial services such as maid
Maid
A maidservant or in current usage housemaid or maid is a female employed in domestic service.-Description:Once part of an elaborate hierarchy in great houses, today a single maid may be the only domestic worker that upper and even middle-income households can afford, as was historically the case...
services, plumbing
Plumbing
Plumbing is the system of pipes and drains installed in a building for the distribution of potable drinking water and the removal of waterborne wastes, and the skilled trade of working with pipes, tubing and plumbing fixtures in such systems. A plumber is someone who installs or repairs piping...
, HVAC
HVAC
HVAC refers to technology of indoor or automotive environmental comfort. HVAC system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer...
, pest control
Pest control
Pest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...
and electricians.
With vehicle dispatching, clients are matched to vehicles according to the order in which clients called and the proximity of vehicles to each client's pick-up location. Telephone operators take calls from clients, then either enter the client's information into a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
or write it down and give it to a dispatcher
Dispatcher
Dispatchers are communications personnel responsible for receiving and transmitting pure and reliable messages, tracking vehicles and equipment, and recording other important information...
. In some cases, calls may be assigned a priority by the call-taker. Priority calls may jump the queue of pending calls. In the first scenario, a central computer then communicates with the mobile data terminal
Mobile data terminal
A mobile data terminal is a computerized device used in public transit vehicles, taxicabs, courier vehicles, service trucks, commercial trucking fleets, military logistics, fishing fleets, warehouse inventory control, and emergency vehicles to communicate with a central dispatch office...
located in each vehicle (see computer assisted dispatch); in the second, the dispatcher communicates with the driver of each vehicle via two-way radio.
With home or commercial service dispatching, customers usually schedule services in advance and the dispatching occurs the morning of the scheduled service. Depending on the type of service, workers are dispatched individually or in teams of 2 or more. Dispatchers have to coordinate worker availability, skill, travel time and availability of parts. The skills required of a dispatcher are greatly enhanced with the use of computer dispatching software (see computer aided call handling
Computer aided call handling
Computer aided call handling is a methodology for managing calls to service providers, such as emergency services, through the use of computer based algorithms in order to make consistent and objective decisions on action to be taken...
).
Manual dispatch systems
The following are examples of manual systems used to track the status of resources in a dispatched fleet.Cards
Card systems employ a set of shelves with a slot for each unit in the dispatch fleet. Each vehicle or resource has a slot in the shelving system. In it, a card, like a time card used to track an employee's work hours, is stored. A time clock, similar to the one that stamps work hours on a time card, is used to stamp event times on each card. At the beginning of a work day, the resource's identifier or other information is handwritten on the card. Each time the resource's status changes, the card is punched in the time clock and a new status entry is handwritten on the card. The card collects a series of entries through the work shift.In a tow truck example, the card might be labeled with the tow car's radio identifier, "Downtown 6" and may be labeled with the vehicle number or data about the capabilities of the specific tow car. It might give a weight capacity, show the unit as a flat bed or cradle snatcher, or mention the unit carries a can of Diesel fuel. The name of the staff on the car might be noted. At the start of a shift, the dispatcher would note the unit "available" and time stamp the card. At the assignment to a call, the call information would be written on the card and the card might be stamped at the moment the assignment is read to the tow car crew. The string of notes and time stamps allows dispatch staff to get a clear picture of the status of a small fleet.
Some systems use shelving with red and green lights and a switch at the back of the card slot. If the resource's card is pushed all the way into the card slot, the switch is actuated and an indicator lamp turns red. This identifies the tow car whose card occupies that slot as not available or assigned to a call. Leaving the card pulled partway out leaves the indicator green, showing the dispatcher that unit is available. Is anyone available? The lights are supposed to give the dispatch staff a snapshot of their resource situation.
A major flaw of this system is that cards are inside shelves and trying to look at an entire set of cards to evaluate the overall situation requires the dispatcher to pull out every card, one at a time, and read it. If two or more resources are sent to the same call, the dispatcher has a lot of writing to do.
Punched tags
Punched tag systems employ a set of pegs with each peg holding tags for one unit in the dispatch fleet. Each vehicle working the current shift has a peg with a tag describing the unit's current status. A time clock, similar to the one that stamps work hours on a time card, is used to stamp times on each tag. At the beginning of a work day, the resource's identifier may be posted above the peg. The unit's start time is stamped and their status is written on the tag. Each time the resource's status changes, a new tag is written and the tag is time stamped in order to log the time the unit's status changed. The peg collects a stack of tags through the work shift.In a tow truck example, the peg might be labeled with the tow car's radio identifier, "Downtown 6" and may be labeled with the vehicle number or data about the capabilities of the specific tow car. It might give a weight capacity, show the unit as a flat bed or cradle snatcher, or mention the unit carries a can of Diesel fuel. The name of the staff on the tow car might be noted. At the start of a shift, the dispatcher would note the unit "available" and time stamp a tag, then hang it on that unit's peg. At the assignment to a call, the call information would be written on another tag and the tag might be stamped at the moment the assignment is read to the tow car crew. The tag would then be hung on that unit's peg. The stack of tags allows dispatch staff to get a clear picture of the status of a small fleet.
Some systems use colored tags to show general categories of events such as "available". For example, each unit that is available might have the fact noted on an orange tag. Is anyone available? A glance at the pegboard shows anybody whose tag is "orange" is available. An repossession might use a yellow tag to identify a service call with a safety issue where the police should be called in the event the tow car crew doesn't check in by radio within five minutes. A blue tag might show a resource is taking a dinner or lunch break.
A major flaw of this system is that tags can easily be posted on the wrong peg, causing confusion. This can be countered by writing unit identifiers on every tag: a lot of work. In colored-tag systems, it's always possible to run out of certain colors of tags, messing up the system. If two or more resources are sent to the same call, the dispatcher has a lot of writing to do.
Plastic icons
In a plastic icon system, the blank panel on the communications console or a nearby wall is fitted with a sheet of VelcroVelcro
Velcro is the brand name of the first commercially marketed fabric hook-and-loop fastener, invented in 1948 by the Swiss electrical engineer George de Mestral...
. The material has vertical stripes painted on it, making a column for each of several possible status conditions. The simplest system is two columns: available and unavailable. Magnetized icons can be used in place of Velcro. The icons can be colored or shaped to identify the type of unit or some other feature of the resource.
Each vehicle working the current shift has an icon placed in the column describing the unit's current status. A log book is used to track times, event details, and other information about calls for service. In a tow truck example, the icon might be labeled with the tow car's radio identifier, "Downtown 6". During a shift, the icon would be moved by the dispatcher into whatever column describes the resource's current condition. Alternatively, there could be columns for some other condition such as the names of move-up or standby points where resources are sent to backfill for busy tow cars.
A major flaw of this system is that icons can easily be misplaced or fall off of the status board. Magnetic objects can damage cathode ray tube displays if they get too close to the display face or housing.
Airline dispatch
In airlineAirline
An airline provides air transport services for traveling passengers and freight. Airlines lease or own their aircraft with which to supply these services and may form partnerships or alliances with other airlines for mutual benefit...
operations in a few countries, a dispatcher
Dispatcher
Dispatchers are communications personnel responsible for receiving and transmitting pure and reliable messages, tracking vehicles and equipment, and recording other important information...
shares legal responsibility for a flight's safety with its pilot, and may delay, divert or cancel a flight if there is reason to do so. This checks and balances mechanism supposedly improves the safety of the dispatch system, although most countries do not use this system and there is no noticeable detriment to flight safety. A dispatcher typically must be licensed by the aviation authority of a country. The examination for the licence requires the candidate to demonstrate knowledge in meteorology and aviation comparable to that required to obtain an Airline Transport Pilot Licence.
Mobile dispatch
In a mobile system, wireless technology is provided for efficient job planning, assignment and efficient job planning through the use of mobile dispatch systems sent out through a mobile network on to a mobile device such as PDAPDA
A PDA is most commonly a Personal digital assistant, also known as a Personal data assistant, a mobile electronic device.PDA may also refer to:In science, medicine and technology:...
. This allows for more flexible management of the workers out in the field as a job can be dispatched to multiple users to accept or reject the job. The benefits of a mobile system as it can then be integrated back into the other software systems used by an organization such as asset management, rostering, and other financial systems.
Capacity and metrics
There is a limit to how many field units can be managed. This varies with circumstances. For example, a parcel delivery service dispatcherDispatcher
Dispatchers are communications personnel responsible for receiving and transmitting pure and reliable messages, tracking vehicles and equipment, and recording other important information...
may encounter higher traffic around Christmas
Christmas
Christmas or Christmas Day is an annual holiday generally celebrated on December 25 by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ, liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days...
. Work is not evenly distributed across time: in any dispatch system there are traditional peaks or busy hours in requests for service. Some workplace cultures will allow longer wait times than others.
Systems may use a voice procedure
Voice procedure
Voice procedure includes various techniques used to clarify, simplify and standardize spoken communications over two-way radios, in use by the military, in civil aviation, police and fire dispatching systems, citizens' band radio , etc....
to reduce talking time, allowing interaction with a larger dispatch fleet. Air traffic control and towing are two examples. The use of abbreviations or standard phrases can reduce the length of a transaction. Capacity may be reduced by relaxed voice procedure such as a delivery dispatcher giving a lengthy description of a customer complaint over the radio.
It's generally accepted that giving field units computers connected with the computer-aided dispatch, or another enterprise system used for dispatch, unloads voice two-way radio channels and increases capacity. Users research information on their terminal or laptop instead of calling in with a request that the dispatcher do it. One source suggests radio traffic drops by 30% when computers are available to mobile users.
Radio
Measurements of communications may reflect dispatch capacity. A partial definition of capacity comes from the number of communications channels required to support a dispatch fleet. Two metrics of channel capacity may be: 1) the number of field units or resources dispatched, and; 2)number of push-to-talk presses per day. A resource may refer to a fire engine, tow truck, taxi, or refuse truck, regardless of how many walkie-talkies, mobile radios, or persons were fielded along with each resource.One suggestion is that 100 to 150 mobiles is the maximum practical on one channel. Another suggests 60-70 units as a maximum. The difference in these two ranges probably reflects the wording. For example, 120 mobiles may mean radios: 60 units each containing a mobile radio and an officer with a walkie talkie. For dispatch systems like take-out food delivery, where life safety is not an issue, delays may be acceptable. Delays increase capacity.
Another possible measure of capacity is system push-to-talk presses. A 187-day study of four Contra Costa County, California
Contra Costa County, California
Contra Costa County is a primarily suburban county in the San Francisco Bay Area of the U.S. state of California. As of the 2010 census, it had a population of 1,049,025...
Sheriffs Department conventional two-way radio dispatch channels showed an average of around 2,500 push-to-talk presses per day. The count was within +/-350 a day across all four primary dispatch channels.
Telephone
Traffic analysis
Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. It can be performed even when the messages are encrypted and cannot be decrypted. In general, the greater the number of messages observed, or even intercepted and...
can be applied to radio or telephone communications.
Most office telephone systems have some facility for recording calling volumes, and incoming call timing. Dispatch centers use Automatic call distribution (ACD) groups which can be evaluated for metrics such as average wait time, abandoned calls, and calls per hour. These numeric data can be entered into spreadsheets for analysis of trends.
In dispatching, US emergency medical services literature suggests that telephone calls to a dispatching facility should be answered in the first few rings. One document suggests emergency calls to dispatch should result in busy signals once per 100 calls during the busiest hour. In business call centers, similar standards are suggested by consultants in order to provide an ideal customer experience and to outperform competing services. Sufficient staffing should be in place so that 90% of emergency calls are, "...answered within 10 seconds, or with no greater than three rings, during the average busy hour," according to one source. Tolerable wait times vary from one culture and region to another: some cultures expect immediate service; others will tolerate waits for some services.
Zone system to assign service calls
Each zone of the grid is identified with a progression of ambulance zones and fire stations. One zone might be labeled: DP241. This means fire station 2, then 4, then 1, then 3 would respond to a fire call occurring inside this zone. If fire stations 2, 4, and 1 were assigned to calls, Station 3 would be sent to this zone. Distal Volunteer Rescue Squad would be first-up for an ambulance call occurring inside zone DP241.
The predefined order is created by persons with expertise in the service being provided, local geography, traffic, and patterns in calls for service. In assigning resources to a zone, decision-makers may consider that responding units must drive around freeways, lakes, or terrain obstructions in order to reach a zone. Zone boundaries and designations will periodically change as communities grow or lessons are learned during day-to-day operations. Consider a zone with an irrigation canal defining one boundary. If a car crashes into the canal, which zone is it in?
Zone systems may include standby, move-up, or backfill points. For example, taxi drivers working in a certain zone in the evening hours may expect night club patrons to need a ride. Consider a standby point at Main Street and Railroad Avenue named N. Some fares will come from radio calls to dispatch. A taxi driver, Car 4, may go to predefined standby location N. In some dispatching systems, the driver will call the dispatcher and report they are available and located at standby point N. The dispatcher may respond by reporting the driver's position in the queue, "Car 4, second N." The first call in this district would go to the driver ahead of Car 4. Car 4 would be assigned the second call.
If automatic vehicle location
Automatic vehicle location
Automatic vehicle location is a means for automatically determining the geographic location of a vehicle and transmitting the information to a requester....
is available, it would display service vehicle locations on a map. The closest unit would be interpreted by the dispatcher looking at vehicle locations projected on the map.
External links
- Emergency Medical Dispatch Trainee Guide, Volume 1 or ISBN 0160485495