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Federal Highway Administration Research and Technology
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Publication Number: FHWA-RD-95-197
Date: December 1996
Development of Human Factors Guidelines for Advanced Traveler Information Systems and Commercial Vehicle Operations: Comparable Systems Analysis
CHAPTER 6. THE OmniTRACS MOBILE COMMUNICATIONS TERMINAL
GENERAL SYSTEM DESCRIPTION AND OBJECTIVES
The OmniTRACS system, developed by QUALCOMM Incorporated, is a two–way mobile satellite communications and vehicle–tracking system designed for use in Commercial Vehicle Operations (CVO). This system was commercially available for use in 1988 and is now currently utilized by over 225 customers and is installed in over 50,000 trucks. The design of the OmniTRACS system was based primarily on the current demands of the CVO industry. Unlike the other six systems included in this report that are still at the prototype or testing phase, OmniTRACS has been introduced into the commercial market and has been favorably accepted since its initial deployment.
The design of the OmniTRACS system was customized to the needs of the CVO customer (i.e., motor carrier/trucking company). CVO customer needs differ from the needs of the typical ATIS user (e.g., leisure driver). One of the greatest costs involved in CVO is related to the amount of idle and wasted time the driver spends in trying to find a telephone to contact dispatch with information such as arrival and departure times, billing information, delays, emergencies, and loading/unloading information. Dispatchers are responsible for the scheduling and routing of up to 60 drivers/tractor units, which means that drivers are often placed on hold or cannot get through at all. This frequently creates a bottleneck in the CVO system that translates into increased costs, low productivity, and driver dissatisfaction. Ultimately, it translates into dissatisfied clients (i.e., shippers and consignees), which motor carriers rely on for business.
The objective of the OmniTRACS system was to enhance the customer's communication with and the control of their CVO equipment (i.e., trucks and trailers). The ATIS/CVO functions provided by OmniTRACS are denoted in table 5. These functions were achieved by designing a Mobile Communications Terminal (MCT) to be installed in each vehicle, which consisted of three hardware units: an outdoor antenna, a communications unit, and a display unit. This satellite–based MCT allows drivers to be in constant touch with dispatchers who also have a computer–aided system to continuously track the location of each driver/truck. Forward host–based data (e.g., load assignments) are sent directly to the appropriate truck or fleet of trucks. This driver–dispatcher data link also allows motor carriers to access vehicle–based data (e.g., driving statistics, engine diagnostics) via optional Vehicle Information Systems. All messages and positioning information from the vehicles are transmitted, via satellite, through the QUALCOMM Network Management Center to dispatch centers nationwide.
Table 5. Comparison of OmniTRACS functions with those from ATIS/CVO systems.
Network Management Center (NMC)
The function of QUALCOMM's Network Management Center (NMC) is similar to the Advanced Traveler Management Systems (ATMS) component proposed in ITS applications. All information from fleet vehicles and dispatch centers passes through the NMC, which monitors and logs messages. Each motor carrier is charged a fee for the number and the length of the messages they transmit. The NMC, where all messages are processed, is located in San Diego, California, and is staffed 24 hours a day. A fully equipped backup station is located in Las Vegas, Nevada.
As the hub for the entire OmniTRACS system, the NMC features two DEC VAX 6410 computer cluster systems (one acts as a backup). All communications are transmitted via satellite through a 7.6–m dish. The satellite service is provided by GTE aboard an existing satellite and QUALCOMM is guaranteed that transponders will be available from one of the three GTE satellites. Communications to the NMC are supported through dedicated leased lines, dial–up services, or time–share networks. QUALCOMM operates the largest transportation communications center in the world via numerous communication protocols supported at the NMC. Further investigation of this NMC seems warranted for future research on Automated Traffic Management Systems functions and design.
QUALCOMM has developed various software products to enhance the dispatcher's organizational and communications tasks. Many different hardware platforms (PC's, LAN's, mid–range, and mainframe systems) can be used to run these programs. These software packages are intended to automate the motor carrier's functions and to integrate with already–existing transportation software available for dispatchers, such as accounting, dispatch, sales order entry, maintenance requests, personnel data, and payroll. The dispatcher's interface to the OmniTRACS system may be the greatest selling point to potential customers. Once the software products are loaded on the company's dispatch computer systems, the dispatch process is automated to a real–time process by linking vehicle information transmitted by the OmniTRACS system. For example, one group of software products dynamically optimized the operations of truckload carriers by considering key facts, forecasts, and management priorities to recommend the right truck for a certain load. This program maximizes revenue per truck per day and minimizes cost. Another group of software programs integrates vehicle information systems and compiles data generated by a vehicle's on–board sensors and subsystems to enhance overall fleet management. The objectives of this optional set of software programs were to provide the capability to produce performance statistics reports, vehicle diagnostics data, and trailer status information.
Vehicle locations are displayed to dispatchers in text format or on a map display, as specified by the dispatcher. Text formats provide the number of miles to the nearest city/landmark and to the nearest large city. Another software package passes position and location history from the host computer to a PC computer with a VGA color graphics monitor for mapping. Mapping features include: displaying major cities, State lines, highways, and roads; aiding in the process of calculating estimated times of arrival (ETA's); allowing reduced–scale capability for the dispatcher to zoom in on a specific vehicle or landmark; entering customer's locations as landmarks on the map (and in text format); color–coding vehicles by class; and displaying current capacity and demand status of the fleet. QUALCOMM's satellite triangulation technique provides position reporting accurate to within 305 m.
Mobile Communications Terminal (MCT) Driver Display Unit
The driver is continuously linked to dispatch through the Mobile Communications Terminal (MCT) display unit mounted in the truck cab. Through this unit, the driver reads incoming messages and assignments, and can send messages to dispatch. While there are few limitations on the content of text messages provided by dispatch, the system is not capable of providing drivers with route guidance and navigational information via map displays. Navigation information is not the focus of the communications link between drivers and dispatchers. The transmission of position and location data through the OmniTRACS system was intended as a benefit for fleet management rather than an enhancement of driver navigation tasks. The design of the driver interface emphasized ease of use and acceptance by truck drivers in their normal operations.
The configuration of each system is different. Several options are available, and each unit can be customized to the customer's needs. After motor carriers understand the various features and optional software packages and how each can enhance their company's functions, QUALCOMM delivers the OmniTRACS hardware components, configures the system, and establishes communications links according to the customer's specifications. They also demonstrate or perform installation procedures, provide Driver's Manuals and Reference Cards for each unit, and suggest training programs to teach drivers and dispatchers how to use the system. This continued relationship with each customer has been the basis for QUALCOMM's evaluation of their design.
The analysis that follows is based on the information obtained from two applications of the OmniTRACS system, each configured to the specific requirements of the motor carrier. Since the system can support a variety of configurations and options to meet the various needs of diverse CVO customers, the analysis was performed at a higher level than for the other systems in this report. Specific design issues relevant to ATIS applications are raised in the context of the applications observed and may not reflect other possible configurations of this system. The emphasis of the analysis was on the interface of the on–board display unit used by the driver.
The Mobile Communications Terminal (MCT) display unit is installed in the cab of trucks as determined by the motor carrier. The dimensions of the display unit are 29 cm long x 19 cm wide x 7 cm deep and weighs 1.1 kg (figure 47). It fits into a support bracket (i.e., holster) that is permanently attached to a sturdy panel. The MCT functions on power from the vehicle and has a coiled power cord that can be extended several feet.
The system is not intended to be used while the vehicle is in motion. Therefore, the MCT is typically installed by the customer so that the driver cannot see text displayed on the screen when the unit is in the holster. The drivers are instructed by the motor carrier to remove the MCT display unit from the holster and read/enter messages when they are parked. Drivers that were interviewed reported that the unit is easily retrieved from the holster located (with one motor carrier) below the dash panel, to the right of their legs, near the floorboard, next to the gearshift. Drivers hold the unit with one hand or support it on their laps or on the steering wheel when reading or entering information.
The keyboard and display terminal of the OmniTRACS MCT is designed to be rugged and portable. All three hardware components, MCT communications unit, and antenna are designed to endure temperatures between –30E C to 70E C and much shock and vibration.
Visual Information Display
The display unit has a 5–cm by 13–cm, back-lit Liquid Crystal Display (LCD) message screen that displays 4 lines of text, 40 characters/line (figure 48). The back lighting can be turned on or off by pressing one of the control keys to the left of the keyboard. The display unit is automatically activated when the vehicle's ignition is turned on and will remain on for a period of time to be established by the dispatcher (up to 60 minutes) after the vehicle is powered down.
The main VIEW STATUS screen (figure 49) appears at start–up and indicates the time (for the driver-specified time zone) and date, whether the system status is "good," number of unread messages from dispatch, and number of messages being sent by the driver. The system has a buffer that allows drivers to send a maximum of three consecutive messages.
The information content of text messages varies depending on the application and can be as long as 50 lines. The system allows various types of informationðCeither sent by dispatch or collected by vehicle monitoring systemsðCto be made available to the driver. There are no hardware limitations as to the content of messages. However, QUALCOMM does provide specific software products capable of providing specialized information links to customers that include the following:
All messages received from dispatch are displayed to the driver in uppercase text (figure 50). Messages created and sent by drivers are seen on the screen in lowercase text (figure 51). The case distinction enables drivers to readily determine the source of messages when drivers review previous messages. Messages can be received or transmitted whether vehicles are stationary or in motion. If desired, an axle sensor option enables customers to halt interaction between the MCT and display unit when the vehicle is in motion. A wake-up timer feature operates when the unit is turned off that "wakes up" the unit at periodic intervals (defined by the dispatcher) and downloads messages.
Upon request, dispatch can send drivers information about routes to a shipper/consignee location if that information is available. The level of information depends on the route planning databases or software connected to the dispatcher's system (e.g., Rand McNally's Mile Maker or ALK's PC*MILER). The routing information can be developed internally by a carrier by creating a database of instructions from actual drivers who have previously made a delivery/pick–up to the same destination.
Two red MESSAGE WAITING lights, one on the front and one on top of the unit, light up when a message is received. The lights flash if one of the messages received is a priority message (i.e., needs immediate driver attention). When the red light to the right of the message screen is lit, it indicates NO SIGNAL from the satellite is being received by the unit's antenna.
Auditory Information Display
The display unit emits a tone (beep) when a message is received from dispatch. The sound level of this tone is adjustable by the driver. The pattern of beeps emitted indicates the priority of the message and corresponds to the flashing of the message waiting lights (i.e., one beep indicates a message was received, three consecutive beeps indicates a priority message was received). Some drivers perceive single beeps to be similar to those heard through other on–board electronics (e.g., CB radio) and report false alarms in which they thought a message was received. They had to repeatedly check the status of the message light to determine whether a message was received.
The unit also emits two beeps whenever the driver presses a key that the system cannot act upon (e.g., pressing READ PREV when there are no previous messages listed). During training and in the Driver's Manual, drivers are told that the system is designed so that any key can be pressed at any time without damaging the system or losing typed information.
User Input (Controls)
The majority of the controls are discrete keys and include dedicated function keys, arrow (cursor) keys, a standard QWERTY keyboard, and a numeric key pad (figure 52). The entire control panel is constructed of an elastomeric–type material and is "splash–resistant" against contaminants. The screen backlight control key allows the driver to set the screen backlighting on or off. The audio control and contrast control rocker switches (continuous settings) adjust the volume of the message waiting beeps and the contrast of the text screen.
The blue dedicated function keys above the keyboard activate specific screens to read or enter information. A driver can access incoming messages by pressing the READ NEXT key; the READ PREV key is used to review a previous message. The memory stores 99 messages that can be reviewed by pressing the READ PREV key. The REPLY key initiates a reply to a message just read. The CREATE MSG key is used to create a new message and the SEND key calls up the option to transmit the entered message. The left and right arrows, ENTER, and DEL keys are used to edit text; and the + or – keys allow the driver to run through a list of company–defined, pre–formatted messages. These pre–formatted, fill–in–the–blank messages are designed to allow motor carriers to structure commonly used messages to minimize the number of characters the driver has to enter. For example, "Departing Information" could be a pre–formatted message in which the driver simply sends the time–stamped message with number of pallets loaded or other information.
The QWERTY keyboard and numeric key pad are used to enter alphanumeric text when creating messages and entering information. Drivers can scroll through a message by pressing the down arrow key. The screen indicates that there is more information beyond what is being displayed by using a 8 and/or 9 to the left of the text.
One of the main objectives in the design of this system was to ensure its ease of use by means of simple function keys. As the system was purchased by motor carriers, requests for additional features were made and those features were slowly incorporated into the system by adding them onto an OPTIONS function that allows access to several screens of information.
All the labels on the controls are black. The top row of dedicated function keys are blue and the rest are white. The Y and N keys, which are used most frequently, are a gray color to distinguish them from the rest. Drivers report that the darker color does allow them to find the Y and N keys easily in daylight conditions, but not in darkened conditions. They reported that tactile information (e.g., an etched key) could be helpful in identifying the two keys in the dark. Most drivers said the screen was easy to read in the dark, but it was difficult to enter messages using the keyboard at night without a cab light on. When prompted, the drivers agreed that having illuminated labels on all keys could make the system much easier to use in reduced–lighting conditions.
The communications unit installed underneath the cab of the vehicle provides the computing capability to send and receive digital (i.e., text) messages to and from the truck. A decoder and microprocessor were designed to provide reliable signal processing capability. The manufacturer provides its own automatic satellite position reporting system to link fleet vehicles with dispatch centers and the NMC. This system utilizes existing electronics and satellite triangulation methods to provide vehicle position reports accurate to approximately 305 m. Drivers reported that the system loses the satellite signal when overhead objects block the direct line of sight between the antenna and the satellite. Position information directly impacts dispatchers' vehicle–tracking tasks and mapping capabilities.
The issue of shared attentional demandsðCof great concern in the ATIS areaðCis not directly relevant with this system when it is used as recommended. This system was designed to be used while the vehicle is stationary. Customers are made aware of the limitations and intent of the system and are given the option of configuring the system to "lock out" the driver when the vehicle axles are in motion. The training materials and sessions provided by the manufacturer instruct drivers not to use the unit when in motion.
The display unit has a warning notice etched into the display explicitly instructing drivers not to use the system while driving (figure 53).
The Driver's Manual also states a similar message:
Never use your MCT while you are driving. This will divert your attention from the road and could lead to a serious accident.
A lesson learned when we interviewed several drivers was that drivers do use the system while driving. When drivers use the system while the vehicle is in motion, the issue of cognitive demand is relevant, just as in ATIS systems. The allocation of attentional resources required to perform a secondary task utilizing an in–vehicle system may hinder driving performance and safety. Insufficient research data exist to set a criteria for attentional resource requirements in a driving task or for secondary tasks. The number of factors and individual characteristics, plus the dynamic and complex nature of the driving task, make it difficult for research efforts to provide useful data. In CVO applications, there is even less data to make such recommendations. However, this issue must be resolved before in–vehicle systems can be confidently designed without jeopardizing driver safety.
In interviews, several truck drivers who admitted using the OmniTRACS system while driving said that they did not feel that it reduced their level of safety any more than the existing systems and paper maps that they already use. The benefits, on the other hand, completely outweighed the current system requirements and increased their job performance.
System Temporal Requirements
The LCD screen seemed to respond at a rate that did not affect data entry tasks. Some drivers reported a slight lag in messages being sent to dispatch, but it was acceptable in most cases. Drivers said the system does not indicate when dispatch reads their messages. In the observed system, the driver was informed that messages were sent to the dispatch center, but they had no idea when the dispatcher received or read the message. This feature did not seem to be a limitation of the system, but an aspect of the procedures developed by the customer.
DESIGN GUIDELINES USED
Human Factors Design Guidelines
The OmniTRACS design team seems to have been composed mostly of personnel from engineering and marketing. The objective of the first prototype was to meet the specific communications needs of commercial vehicle operations. There were no human factors members in the design team and it is uncertain whether human factors guidelines were used to design the driver or dispatcher interface. Once the needs of the CVO industry were delineated, the design team relied on available technology and cost–benefit decisions in selecting the components of the driver interface.
The evaluation of this system by QUALCOMM has been based primarily on its market use and consumer feedback. The success of the system was measured by the increased productivity and reduced costs of the customer (i.e., motor carriers, trucking companies), driver comments, and design team review. After company–mandated beta testing, the prototype was installed in a fleet of 5,000 vehicles belonging to the largest truck load carrier in the United States. This resulted in field–tested, positive reviews from various drivers, interested customers, and other members of the CVO industry. While engineers working on improving the system admit that the system could be enhanced considerably if customers supported the increase in cost, they also say the customers like the system as designed. The heavy use of this system and positive customer feedback has led QUALCOMM to feel that the system is well designed and meets the needs of the CVO industry. Therefore, few alterations in the driver interface have been made since the first prototype, although changes may occur in the future.
Some of the design criteria emphasized environmental abuse (e.g., truck vibrations, temperature, humidity, impacts) in the trucking industry. For example, the existing size of the LCD screen seemed appropriate for the anticipated temperatures and vibrations in long–haul trucks, and integrating the display screen and keyboard into one "unit" or "terminal" was thought to be more practical and would endure more impacts.
Ease of installation was a primary design goal. All three components of the MCT system were designed to be installed in 2 to 4 hours and would be easily configured to different types of truck styles. The holster for the display unit can be mounted on any existing panel, allowing the customer to install the MCT to fit the types of trucks in their fleet.
The interface was designed to be user–friendly to a population with little computer knowledge and perhaps a dislike for computer–based products. The use of dedicated function keys was expected to simplify the interface and reduce the number of menu levels necessary. This guideline resulted in what drivers report to be an easy system to use. The design team is currently upgrading the system's functions. Whether these added features will require introducing more menu levels/options to each dedicated function key or integrating more dedicated function keys has yet to be determined.
Guidelines in the development of a training program revolved around simplicity, brevity, and ease of understanding. One customer developed its own training program to instruct drivers on the proper use of the MCT. Two hours of classroom demonstration were given as part of the company's general training program. Additional in–vehicle instruction also was integrated into the training. The Driver's Manual was designed to be brief, easy to read, and easy to find necessary information. A Driver's Reference card also was provided that showed drivers how to perform the most essential tasks (i.e., reading and sending messages).
[OM 01] LCD DISPLAYS CAN PRODUCE GLARE WHEN DIRECT SUNLIGHT IS SHINING IN THE VEHICLE
[OM 02] ADJUSTABLE DISPLAYS ALLEVIATE GLARE PROBLEMS
[OM 03] DIRECT SUNLIGHT MAKES THE ACTIVATION OF WARNING LIGHTS DIFFICULT TO DETECT
[OM 04] LCD DISPLAYS REQUIRE BACKLIGHTING AND CONTRAST CONTROL
[OM 05] TEXT–BASED DISPLAYS THAT LACK "WRAP–AROUND" CAPABILITY CAN BE CONFUSING
[OM 06] DRIVERS SOMETIMES SPILL BEVERAGES ON IN–VEHICLE EQUIPMENT
[OM 07] AUDITORY SIGNALS MAY BE MASKED BY, OR CONFUSED WITH, OTHER SOUNDS AND NOISES
[OM 08] TEXT–BASED ROUTE GUIDANCE DISPLAY IS PREFERRED OVER VERBAL INSTRUCTIONS AND MAPS
[OM 09] NAVIGATION/ROUTE GUIDANCE FEATURES ARE NOT ESSENTIAL TO LONG–HAUL TRUCK DRIVERS
[OM 10] NAVIGATION/ROUTE GUIDANCE FEATURES CAN BE HELPFUL WITHIN CITY LIMITS
[OM 11] FOLLOWING TEXT–BASED ROUTE GUIDANCE INFORMATION IS NOT DIFFICULT
[OM 12] PRE–FORMATTED MESSAGES DECREASE THE AMOUNT OF DATA INPUT NEEDED IN REQUESTING ASSISTANCE
[OM 13] DEDICATED EMERGENCY RESPONSE BUTTON IS VALUABLE FOR TRANSPORTING CERTAIN TYPES OF CARGO
[OM 14] ROAD ASSISTANCE REQUESTS CAN BE IMPEDED BY A TRUCK POWER FAILURE/SHUTDOWN
[OM 15] KEYBOARDS WITH QWERTY LAYOUT ARE PREFERRED OVER ABCDEF LAYOUT
[OM 16] DEDICATED FUNCTION CONTROLS SIMPLIFY THE INTERFACE
[OM 17] DRIVERS FIND GREAT BENEFIT IN VIEWING MESSAGES ON THE SCREEN WHILE DRIVING
[OM 18] DRIVING PERFORMANCE USING IN–VEHICLE DISPLAYS MAY BE COMPARABLE TO USING PAPER MAPS OR OTHER EQUIPMENT
[OM 19] DRIVING WHILE HOLDING THE DISPLAY CAN LEAD TO INCREASED HEAD–DOWN TIME
[OM 20] DISPLAYS MOUNTED AT EYE HEIGHT AND ARM'S LENGTH REDUCE HEAD–DOWN TIME WHEN DRIVING
[OM 21] MANUFACTURERS MAY BE RELUCTANT TO MARKET DEVICES TO BE USED WHILE DRIVING
[OM 22] TRAINING PROGRAMS ARE AN ESSENTIAL PART OF THE SYSTEM
[OM 23] THE ABILITY TO COMMUNICATE WITH DISPATCH WITHOUT LEAVING THE VEHICLE IS PERCEIVED TO BE THE GREATEST UTILITY
[OM 24] PAGERS ALLOW DRIVERS TO BE NOTIFIED OF INCOMING MESSAGES WHEN AWAY FROM TRUCK
[OM 25] CUSTOMER–DRIVEN DESIGN APPROACH PROVED TO BE BENEFICIAL
[OM 26] HUMAN FACTORS DESIGN GUIDELINES WERE NOT USED
[OM 27] DESIGN CRITERIA WERE MEDIATED BY MARKET DEMANDS
[OM 28] DESIGN CRITERIA WERE DEPENDENT ON KNOWN SYSTEM ENVIRONMENTAL FACTORS
[OM 29] SYSTEM DESIGN REVOLVED AROUND INSTALLATION REQUIREMENTS