Software Requirements Specification (SRS)
Spinning Dragon Cruise Control
Authors: Nathaniel Henry, Forrest Yockey, James Solomon, Peter
Chen, Brian Duncan
Customer: William Milam
Instructor: Dr. Betty H.C. Cheng
1
Introduction
This software requirements specification (SRS) document covers a brief introduction
consisting of this document's purpose, scope, the definitions, acronyms, and
abbreviations of the terms used in this document, and the overall organization of this
document.
The next section gives the overall description of our system. This overall description
includes a product perspective, product function, user characteristics, constraints,
assumptions and dependencies, and apportioning of requirements.
After that we provide the specific and modeling requirements, respectively.
In prototype section is containing information about our system's prototype. This section
includes how to run the prototype and some sample scenarios.
The last two sections of this document contain references and our point of contact.
1.1
Purpose
The purpose of this SRS is to describe the details of the Spinning Dragon Cruise Control
(SDCC) system and all subsystems. Moreover, this document explains the purpose of
each subsystem, the features of said subsystems, and the interactions between subsystems
and external inputs. This document's intended audience includes the developers of the
SDCC system, as well as the stakeholders and interested parties in such a system
1.2
Scope
The Spinning Dragon Cooperative Adaptive Cruise Control system is an automotive
electronic control system designed to assist the driver in maintaining control over a
vehicle in a variety of conditions and situations. More specifically, this system provides
automated control over the vehicle by attempting to maintain constant vehicle speed
based on input from the driver and communication with other vehicles. This software is
intended to partially automate vehicle control while allowing the driver to override the
system whenever they choose to do so. This system is designed to provide convenience
to the driver and help improve traffic flow while maintaining safe control over the motion
of the vehicle.
1.3
Definitions, Acronyms, and Abbreviations
This section of the SRS contains definitions, acronyms, and abbreviations for the
terminology used to describe our system throughout this document.
Term
Definition
CACC
Cooperative Adaptive Cruise Control – the system described in
this document used to maintain constant vehicle speed with
respect to input from the driver and communication with other
vehicles.
Following Distance
The distance between the driver’s vehicle and the vehicle just
in front of it.
Target Vehicle
A vehicle that the CACC system detects in its forward path.
ACC
Adaptive Cruise Control – a trimmed down version of the
CACC represented here. ACC is a system that includes the bare
essentials necessary to maintain a following distance behind a
target vehicle.
CAN Bus
Controller-Area Network bus- the physical connection that
allows for subsystems of the CACC system to communicate.
All messages sent within the car are sent through the CAN Bus.
Messages are sent as codes to the whole car not to a particular
destination
CC
Cruise Control – the standard system present in most vehicles
to maintain a constant speed on the road.
Communication
Occurs between two automobiles with CACC over a wireless
link. It is used to distribute information among vehicles and
communicate with infrastructure.
Driver
Person who is operating the vehicle
Environmental Factors
Unpredictable, external conditions (such as slippery roads or
rain) that may affect any of the subsystems that makes up the
CACC.
Platoon
A grouping of vehicles that are linked through their enabled
CACC systems, attempting to streamline transportation.
SRS
Software Requirements Specification – this document that fully
explains all aspects of the CACC.
Subsystem
A subsystem is a grouping of sensors or actuators designed for
a specific task. The CACC is made up of several interconnected
subsystems.
Vehicle
The vehicle described is a standard automobile with CACC.
GPS
Global Positioning System – A navigation satellite system that
can provide the vehicle’s speed and location.
Object
Any entity on the road. Can consist of other vehicles, people,
animals or other inanimate entities.
Radio Communication
A subsystem that communicates with target vehicles and
trailing vehicles.
Radar Sensing
A subsystem that detects, identifies, and tracks target vehicles.
Camera Sensing
A subsystem that visually identifies target vehicles and
estimates distance and relative speed.
Radio Transponder
A subsystem that gives vehicle id information to a requesting
trailing vehicle.
Vehicle Controller
A subsystem that coordinates all other CACC subsystems and
maintains vehicle state and operating environment information.
Brake by Wire
Regulates vehicle speed by applying brakes when commanded.
Electronic Throttle
Control
Regulates vehicle speed by adding and removing power.
Vehicle ID
The unique identifier number of a vehicle.
Status Message
The state that the vehicle is in.
DSRC
Dedicated short-range communications are wireless
communication channels specifically designed for automotive
use and a corresponding set of protocols and standards.
1.4
Organization
The second section of this document, the Overall Description, gives an overview of how
the product works. It describes the major functions that the software performs, the
intended users, a list of constraints, and assumptions regarding the system.
The third part of this document, the Specific Requirements, is an enumerated list of the
requirements that the system fulfills.
The fourth section of this document, the Modeling Requirements section, explains how
the software is designed to meet requirements. In this section diagrams and their
associated explanations are used to visualize and specify how the software functions.
The fifth part of this document, the Prototype, gives an overview on how to access and
run the prototype and includes sample scenarios of the system.
The sixth section of this document, the Reference, gives a list of all documents referenced
in the Software Requirements Specification.
The seventh and final section of this document, the Point of Contact section, gives
information on how to obtain more information on this document and product.
2
Overall Description
The SDCC system is one of the many electronic systems available to modern vehicles
and a part of an increasing number of production vehicles. It is software on a central
vehicle controller that builds on the standard cruise control system features into an
autonomous system. Where a standard cruise control system allows for a driver to set a
speed, a CACC system may use sensors and other subsystems to automatically alter the
speed and give information and warnings to the driver. SDCC monitors radar, camera,
GPS, and radio systems to autonomously control the vehicle via electronic braking,
throttle, and steering systems
2.1 Product Perspective
SDCC is a system that gives autonomous traffic adaption based on communication with
other vehicles. Traditional cruise control systems allow the driver to set a speed for the
vehicle and to increase or decrease the speed. ACC allows the vehicle to automatically
increase or decrease speed based on traffic around the vehicle. In CACC, the camera,
GPS, radio, and radar system interface with the vehicle controller via the vehicle’s CAN
Bus. The vehicle controller handles all messages sent from these systems. Using the
GPS, radar, and camera subsystems, the vehicle controller monitors the vehicle’s
surroundings and set the cruise speed appropriately by electronically controlling the
throttle and brakes to increase and decrease speed. To extend the features of the adaptive
cruise control system, this system also communicates with other vehicles using radio
communication and negotiates with those vehicles to form platoons. The platoon
increases the overall system’s effectiveness, as each leading vehicle shares information,
such as vehicle speed and status, with vehicles behind them.
The user interface has the following constraints:
- Turn system on and turn system off buttons
- Increase and Decrease, set, and resume cruise speed buttons
- Notification of nearest vehicle (or target vehicle in platoon) gap distance
- Warnings (target vehicle slows down) and errors are shown on the user’s display
console.
- Crash imminent warning system: Users are notified on the dashboard with Red
LEDs and a beeping alarm
The hardware systems have the following interface constraints:
- The system initializes with a fixed amount of memory and allows for only a fixed
number of possible target vehicles.
- Radar is the primary target acquisition device, camera is secondary.
- The radar maintains vision of all objects within in a direct line of sight within
150ft on a 180 degree arc in front of the vehicle.
- All subsystems must not have any errors for CACC mode to be engaged.
- Once the system is turned on, it is always running unless it is canceled by the
driver or an error occurs.
The software interface has the following constraints:
-
2.2
If any object is determined to be trackable by one of the subsystems, the vehicle
controller must add that object in the system.
Events, actions, and warnings are conveyed to the vehicle controller through the
CAN Bus. The vehicle controller must then make decisions on those messages
The vehicle controller must manage situations of conflicting messages, for
example, when simultaneously a “user increase cruise speed” message and “target
vehicle slowing” message is sent.
Product Functions
This section of this SRS specifies all major functions of the SDCC system with respect to
the customer supplied specifications.
- System On: check if all subsystems are working, set cruise to current vehicle speed,
begin adaptive cruise systems, and begin communication cruise systems.
- System Off: Message communicating vehicles, shutdown cruise systems other than
radio communication.
- Set Speed: Increase set cruise speed, notify communicating vehicles.
- Set Gap Distance: Update subsystems so that target vehicle is followed at desired
distance.
- Detect Vehicle: The Radar system gives the location metrics of a detected target to the
vehicle controller once every second.
- Update Position: The GPS system continuously updates the vehicle controller of the
vehicle’s exact position. This information is used to monitor upcoming traffic conditions
and can be shared with other vehicles.
- Identify Target: The Camera system continuously identifies the target vehicle for
following.
- Estimate Distance: The Radar system calculates the distance of the target vehicle for
following.
- Estimate Relative Speed: The Radar system estimates the relative speed of target
vehicle for following in adaptive situations.
- Speed Control: The Electronic Throttle Control applies throttle to maintain and increase
speed based on the vehicle controller’s set speed and target vehicles speed and gap
distance. The Electronic Throttle Control deactivates when in a state of deceleration.
- Brake: The Brake by Wire system must apply brakes as required by the vehicle
controller.
- Send Message: The Radio system is responsible for updating surrounding CACC
vehicles with Spinning Dragon vehicle’s ID, speed, location, and platooning status.
- Receive Message: The Radio system is responsible for listening to surrounding CACC
vehicle messages. On receive the radio system updates the vehicle controller with IDs,
speeds, locations, and surrounding vehicles platooning status.
2.3
User Characteristics
The user of the CACC system is expected to have a vehicle operator’s license and a basic
knowledge of both the rules of the road and the operation of a standard car. The user is
also expected to be capable of learning how to operate CACC systems.
2.4
Constraints
The system uses static memory. There is no garbage collection. Memory for all objects
is accounted for and they are removed from memory when no longer needed.
SDCC must operate within safe following distance. When in adaptive mode, the system
must always maintain at least a half-car length per 10 mph, or at minimum, 30 feet of
following distance.
Though the driver can pick their desired following distance,
Spinning Dragon must update this based on traffic conditions.
Adaptive Cruise Control requires the Camera and Radar systems to be functioning, while
Cooperative Adaptive Cruise Control requires all systems to be working. In the event of
imminent crash detection the (CACC) system turns off, a message is sent to the brake
system to pressurize and be ready for full deployment, and the radio system sends out a
warning message to all surrounding vehicles. Other than imminent crash, CACC does
not ever disengage to a lower level (ACC or CC) without being engaged by the driver; if
there is an error or an imminent crash is detected, the system shuts off.
For a vehicle platoon to form, two vehicles must be going the same direction in the same
lane, both vehicles must have a CACC system, both CACC systems must be turned on,
the vehicles’ controllers must indicate that the vehicle is capable of supporting
platooning, and the drivers must accept platooning. Additional vehicles can enter a
platoon that is already formed by following the constraints above.
The vehicles communicate with a DRSC 802.11p protocol that allows channel switching
to maintain signal and error checking.
2.5
Assumptions and Dependencies
It is assumed that a cruise control system is already implemented. It is also assumed
that the vehicle driver is familiar with driving a basic cruise control system car. The user
interaction with the Spinning Dragon CACC system is minimal: it is only required that
the user be able to react to the messages by accepting them or selecting yes or no.
2.6 Apprortioning of Requirements
There was some discussion provoked by other groups as to the consideration of
environmental factors (such as rain or slippery roads) that would affect following
distance or braking capabilities. These ideas were not present in the original project
specifications and could be added later if necessary.
The original project specifications also made mention of extra feature such as lane
keeping and obstacle avoidance. These extra features have very little to do with the
design of the CACC system, and the hardware and software required to implement these
features are not present. These features may be added later.
3
Specific Requirements
The specific requirements section of this SRS document yields a list of enumerated
requirements specified by the customer. The SDCC system is designed according to these
specified requirements, with an exception for those requirements related to the functions
discussed in section 2.6.
1. There is no dynamic memory allocation in automobiles. There is no object oriented
programming involved and no garbage collection. Instead it uses fixed memory and a
set number of targets. Everything in memory is accounted for, allocated, and deallocated correctly.
2. Following Distance
2.1. Following distance is determined by the driver.
2.2. Following distance is between 30 and 150 ft.
2.3. Distance is based on ½ car length for every 10 mph.
3. Objects
3.1. Objects closer to the vehicle are higher priority.
3.2. GPS can help discern which objects are moving and which are stationary.
4. If any components of the CACC system are not functioning, then the system should
not turn on.
5. Targets are acquired through the use of the sensors on the car. Sensors include:
5.1. Radar
5.2. Camera
5.3. GPS
6. Radar
6.1. Main form of target acquisition.
6.2. Radar is necessary for both CACC and ACC.
6.3. Radar is only capable of “seeing” the cars in front of it (no sensing around
vehicles).
6.4. Radar has a range of 150 feet and 180 degree field of view in front of the vehicle.
7. Radio
7.1. Sends out a message once a second in every direction regardless of whether or
not other vehicles are around.
7.2. The cars radio communicates by using DSRC in the 802.11 range.
7.3. A message contains the following
7.3.1. Vehicle ID
7.3.2. Speed
7.3.3. Direction
7.3.4. GPS location
7.3.5. Status message
7.3 A message is sent to all surrounding vehicles if a collision is imminent.
7.4 Radio transmission can be on even if CC is not on.
8. GPS system
8.1. Provides constant information on the location of the car.
8.2. Combines this information with geographic information (information about the
locations of all buildings, vehicles, and terrain) to help eliminate stationary
objects as targets.
9. Camera
9.1. Mounted on the front of the car as low as possible.
9.2. Camera captures still frames and discerns between vehicles and stationary
objects.
10. Radar Transponder
10.1.
Gives vehicle ID information to requesting trailing vehicles in order to
establish a radio link between vehicles.
11. Platooning
11.1.
Enabled when the following criteria are met.
11.1.1 2 vehicles going the same direction and approximately the same speed.
11.1.2 Both vehicles are in the same lane.
11.1.3 Driver agrees to enter platoon by accepting a platooning message via the
user interface. If after 5 seconds there is no response, then do not enter the
platoon.
11.2 Changing lanes disengage platooning
12 The CACC system should disengage under certain conditions including:
12.1 Manual breaking occurs
12.2 The cancel button is pressed
12.3 A failure of system component (notify driver)
12.4 Communication is lost (notify driver)
12.5 Changing gears
12.6 Traction is lost and car spins out
13 CACC, ACC, and CC systems are only active above 25 mph. If the vehicle is
below 25 mph, the system will turn off.
14 If a collision is imminent, then notify the driver with flashing LED lights on the
dashboard and beeping sounds.
4
Modeling Requirements
The modeling requirements section of this SRS describes the bridge between the
application and machine domain by utilizing use-case, class, state, and sequence
diagrams. These diagrams also provide a more functional view of the SDCC system.
Figure 1, case diagram for Cruise Control system
Use Case:
System On
Actors:
Driver
Description:
The driver presses the “On” button to turn the system on. The
system initializes and checks that all subsystems are functioning.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
4
Dependent Use
Cases:
N/A
Use Case:
System Off
Actors:
Driver
Description:
The driver presses the “Off” button to turn the system off. The
system and all subsystems proceed to shut down. The system can
also turn off when a crash is imminent or when an error occurs
with the system.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
1, 12, 14
Dependent Use
Cases:
N/A
Use Case:
Speed Control
Actors:
Driver
Description:
The driver can change the speed of the vehicle by pressing the “+“
or “-“ button. The throttle control or brake by wire then increases
or decreases the speed of the vehicle as necessary
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
2,
Dependent Use
Cases:
N/A
Use Case:
Set Speed
Actors:
Driver
Description:
The driver sets the speed of the vehicle by pressing the “Set”
button. This system then maintains a constant speed.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
13
Dependent Use
Cases:
Coordinate Vehicle Systems
Use Case:
Set Gap Distance
Actors:
Driver
Description:
The driver enters a desired gap distance based on the number of
car lengths between each vehicle.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
2
Dependent Use
Cases:
N/A
Use Case:
Send Message
Actors:
Driver, Target Vehicle
Description:
The system is able to send messages to other vehicles with CACC
systems equipped.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
7, 11
Dependent Use
Cases:
N/A
Use Case:
Receive Message
Actors:
Driver, Target Vehicle
Description:
The system can receive messages from other vehicles with a
CACC system equipped. The system can also display messages
to the driver.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
7, 11
Dependent Use
Cases:
N/A
Use Case:
Enter Platoon
Actors:
Driver, Target Vehicle
Description:
The driver and a target vehicle are able to enter a platoon if a
platooning message is accepted by the driver.
Type:
Primary
Includes:
N/A
Extends:
N/A
Cross-refs:
11
Dependent Use
Cases:
N/A
In the following diagram, the class diagram is shown for the SDCC system. In each box,
the name of the class is in bold at the top. Below the class name, the attributes
(variables) of each class is listed. In the bottom portion of each box are the operations
that each class has. Each line between the classes shows the corresponding associations
between the classes.
Figure 2, class diagram for cruise control system
Vehicle Controller
Main controller of CACC
Relationships
Vehicle Controller connects to all sensors
(Camera Sensing, GPS System, Radar
Sensing, and Radio) and detects the vehicle
information. It is also linked to the Brake
By Wire and Electronic Throttle Control to
control the speed, and it sends/receives
messages through radio system.
Attributes
vehicle ID
Vehicle's ID
speed
Vehicle’s current speed
direction
Vehicle’s direction
GPS location
Location of the vehicle
status
Vehicle’s status
gap distance
The minimum Gap distance allowed
Operations:
on()
Ability to turn on the CACC
off()
Ability to turn off the CACC
set speed()
Ability to set the speed
set gap distance()
Ability to set the gap distance
UML Extensions
N/A
Car
Contains information of the vehicle
Relationships
It connects to all the sensors (Camera
Sensing, GPS System, Radar Sensing, and
Radio) and the Vehicle Controller when
they need data of the vehicle. And it also
supports the Radio Communication.
Operations:
detect speed()
Detect the current vehicle’s speed
update()
Update the current vehicle’s information
get information()
Get the current vehicle’s information
connect radio()
Connect to target vehicle’s radio
UML Extensions
N/A
Radar Sensing
Detects and IDs other vehicles
Relationships
It detects others vehicles and takes IDs
from them and send the data back to
Vehicle Controller, and GPS System to
help separate between the vehicles and
objects.
Operations:
detect vehicle()
Detect vehicles around your vehicle
UML Extensions
N/A
Radio Communication
Communicate with other vehicles and
infrastructures
Relationships
Vehicle Controller controls this system and
sends/receives messages through this. It
needs Radar Transponder’s support to
connect to other vehicles.
Operations:
send message()
Send message to the target vehicle
receive message()
Receive message from other vehicles
UML Extensions
N/A
Electronic Throttle Control
Speed control by adding or removing
power
Relationships
Vehicle Controller decides if it is going
power up or down
Operations:
speed control()
Adjust the current speed
UML Extensions
N/A
Brake By Wire
Regulate speed by braking
Relationships
Vehicle Controller decides if it is going to
brake
Operations:
brake()
Brake the vehicle
UML Extensions
N/A
Radar Transponder
Establish radio links between vehicles
Relationships
Vehicle Controller asks it to get a detected
vehicle’s information from Radar Sensing
and the helps Radio Communication to
connect with the target vehicle
Operations:
establish radio link()
Establish radio link to the target vehicle
UML Extensions
N/A
GPS System
Maintains vehicles information
Relationships
Vehicles Controller uses GPS to update the
current position, and GPS also aids Radar
Sensing in differentiating between vehicles
and fixed objects
Operations:
update position()
Update the current vehicle’s position
eliminate object()
Eliminate objects from the vehicles
UML Extensions
N/A
Camera Sensing
Identify target vehicle and estimate
distance and speed
Relationships
Vehicle Controller calls the Camera
Sensing to identifies the target vehicle and
other information
Operations:
identify target()
Identify the target
estimate distance()
Estimate the distance from other vehicle
estimate relative speed
Estimate relative speed to other vehicles
UML Extensions
N/A
In the Figure 3, state diagram, CACC is initially in the off state. Radio is separate
from the CACC, which can be run independently. When you turn on the CACC, you
can set your own speed x and gap distance y. From start the CACC goes to the update
state. When the current speed is different from the speed x, CACC starts the Throttle
control to adjust the vehicle speed to x. When CACC started, the sensors also
automatically activate. There are three different sensors: camera, GPS, and radar.
Radar doesn’t only detect the vehicle but can also support the radio to connect to other
vehicles. Then radio can communicate and send messages to other vehicles. When
one of the sensors stops working, the CACC shuts down and gives the control to the
driver and issues a warning. And if the sensors detect the object or vehicle get closer in
y distance, the CACC breaks to decrease the speed. If the crash is imminent, then the
CACC locks the seat belt and gives a warning to driver, and the CACC is then shut down.
There are some other cases that turn off the CACC. Driver can manually turn off the
CACC, break the vehicle, and change lanes. If the failure of the CACC system occurs
or the vehicle loses control, then the CACC shuts down.
Figure 3, state diagram for cruise control system
In the following sequence diagrams, figures 4.1, 4.2, and 4.2, the sequence begins with
the Vehicle Controller (CACC) turning on, and the CACC then calls Radar Sensing to
detect vehicles around your vehicle. To separate between vehicles and objects, radar
calls the GPS System (GPS) to eliminate objects. After that, radar gets the target
information by connecting to the Car (target). Then target then sends back the required
information to the CACC. At the same time, the CACC keeps updating the current
position by calling GPS, and GPS returns the vehicle’s current position to the CACC.
CACC also keeps identifying anything in front of driver’s vehicle by calling Camera
Sensing (camera). Camera returns any object or vehicle in front of the driver to CACC.
All the status messages mentioned before are updated to Car (mycar). And the
information retrieved by radar can be used to help CACC to call the Radar Transponder
(transponder) and transponder can have the radio connect with the target. After the
connection is ready, CACC can send messages to the target through Radio
Communication (radio). Also the CACC always detects its own speed by calling mycar.
If the speed is too fast, then CACC calls Brake By Wire (brake) to slow down the
vehicle’s speed. The driver can also set the speed of vehicle by calling CACC, and
CACC then calls Electronic Throttle Control (throttle) to adjust the speed.
Figure 4.1, sequence diagram for sensors delectation
Figure 4.2, sequence diagram for communication
Figure 4.3, sequence diagram for speed control
5.
Prototype
Our prototype recreates the dashboard of a car. Our prototype simulates the buttons
available for turning on and off the cruise control as well as adjusting the speed and
following distance; also the accelerator and breaks are available. It also represents the
road with our car and cars in the immediate vicinity. The user is able to adjust speed and
following distance, press the accelerator and break, activate platooning and respond to
failures. The user is able to load some scenarios such as following a car, platooning with
a car and an imminent collision.
5.1
How to Run Prototype
Our prototype is implemented in Java. Access to Java is necessary to run our prototype.
Any browser with Java installed is able to run our prototype. The URL of our prototype is
5.2
Sample Scenarios
Figure 5, prototype sample diagram
The diagram above illustrates a sample scenario that the prototype produces. In this
scenario, the driver’s vehicle is in a platoon with the vehicle just ahead of it. The target
vehicle unexpectedly decelerates quickly and the driver’s vehicle does not have enough
time to react. The CACC senses that a crash is imminent. The CACC then turns itself
off and warns the driver through a panel of flashing LED lights on the dashboard and by
text on the driver’s LED display.
6
[1]
[2]
[3]
References
de Bruin, D. Kroon, J. van Klaveren, R. Nelisse, et al. “Design and Test of a
Cooperative Adaptive Cruise Control System”. Intelligent Vehicles Symposium,
2004 IEEE. 08 October, 2004.
Duncan, Brian, et al. “MSU Software Engineering Spinning Dragon Cruise
Control”. Department of Computer Science Michigan State University. October
2011. < http://www.cse.msu.edu/~435cruise2/index.html >.
Laumonier, Julien, Charles Desjardins and Brahim Chaib-draa. “Cooperative
Adaptive Cruise Control: a Reinforcement Learning Approach“. DAMAS
Laboratory, Department of Computer Science and Software Engineering, Laval
University, Canada. 2006.
[4]
[5]
Milam, William, Betty H.C. Cheng. “Cooperative Adaptive Cruise Control”.
Department of Computer Science Michigan State University. October 2011.
Nowakowski, Christopher, Steven E. Shladover, Delphine Cody, et al.
“Cooperative Adaptive Cruise Control: Testing Driver’s Choices of Following
Distances”. Institute of Transportation Studies University of California,
Berkeley. November 2010.
7 Point of Contact
For further information regarding this document and project, please contact Prof. Betty
H.C. Cheng at Michigan State University (chengb at cse.msu.edu). All materials in this
document have been sanitized for proprietary data. The students and the instructor
gratefully acknowledge the participation of our industrial collaborators.