Concept
of Operations and
Voluntary Operational Requirements
for
Forward
Collision Warning Systems (CWS)
and
Adaptive Cruise Control (ACC) Systems
On-board Commercial Motor Vehicles
|
July
2005 |
Foreword
The Federal Motor Carrier Safety Administration’s (FMCSA's)
safety goal is to reduce the number and severity of large truck fatalities and
crashes. During the last several years, FMCSA has collaborated
with the trucking industry to test and evaluate several on-board safety systems
for commercial motor vehicles to increase the safety and security of all roadway
users. FMCSA is now promoting voluntary adoption of these
systems within trucking fleets by initiating steps to work closely with the
trucking industry to define vendor-independent, voluntary requirements.
The purpose of this document is to relay a better understanding of the functions
of on-board safety systems for vehicle stability and to provide insight into
the safety and efficiency benefits of using the systems. This document describes
the concept of operations and voluntary requirements for Collision Warning Systems
and Adaptive Cruise Control (ACC) systems for large trucks
greater than 10,000 pounds gross vehicle weight rating (GVWR).
Concepts of operations provide information about how each user interacts with
these safety systems and their operational conditions. Voluntary requirements
describe features and functions used to define the safety systems and their
operational functionality. The information has been developed in collaboration
with trucking industry stakeholders, including representatives from manufacturers,
insurance companies, commercial vehicle carriers, drivers and academia.
The results from this project can be used by motor carriers as system guidelines
for voluntary adoption of on-board safety systems within their trucking fleets.
This is a final report developed under FMCSA’s deployment of on-board
safety system program. It does not supersede an earlier report on the subject.
Notice
This document is disseminated under the sponsorship of the Department of Transportation
in the interest of information exchange. The United States Government assumes
no liability for its contents or use thereof.
This report does not constitute a standard, specification, or regulation.
The United States Government does not endorse products or manufacturers. Trade
or manufacturers' names appear herein only because they are considered essential
to the object of this document.
Acknowledgements
FMCSA wishes to acknowledge the efforts of those in the government, academia,
research institutions and industry who contributed their knowledge and expertise
to this effort. Those individuals include Carl Kirk and Robert Braswell of the
Technology and Maintenance Council; Marty Fletcher of US Xpress; Jim Kennedy
of McKenzie Tanklines; Ron Knipling, PhD of the Virginia Tech Transportation
Institute; Scott Claffey of Great West Insurance Company; Dave Melton of Liberty
Mutual Research Institute for Safety; Anne McCartt, PhD of the Insurance Institute
for Highway Safety; Rick Craig of the Owner Operators Independent Drivers Association;
Bill Gouse of the American Trucking Associations; Tom Moses of the Spill Center;
Bob Interbitzen of the National Private Truck Council; Mike Formica and Dean
Pomerleau, PhD of Assistware; Bill Patrolia of Iteris; Meny Benady of Mobileye;
Kevin Romanchok, Jim Szudy, and Richard Beyer of Bendix; Alan Korn, Richard
Romer, and Mike Lambie of Meritor WABCO; Greg Shipman of Delphi; Tom Mattox
of Eaton VORAD; Skip Yeakel of Volvo; Charlie Groeller of Mack Trucks; Paul
Menig of Freightliner; and Dan Murray of the American Transportation Research
Institute.
Technical Report
Documentation Page
1. Report
No.
FMCSA-MCRR-05-007
|
2. Government
Accession No. |
3. Recipient's
Catalog No. |
4.
Title and Subtitle
Concept of Operations and Voluntary Operational Requirements for Automated
Cruise Control/Collision Warning Systems (ACC/CWS)
On-board Commercial Motor Vehicles |
5. Report
Date
July 2005 |
6. Performing
Organization Code
|
7.
Author (s)
Amy Houser (FMCSA), John Pierowicz (Calspan Corp.), Roger McClellan (Calspan
Corp.) |
8. Performing
Organization Report No. |
9.
Performing Organization Name and Address
Calspan Corporation
4455 Genesee Street
Buffalo, NY 14225 |
10.
Work Unit No. (TRAIS) |
11. Contract
or Grant No.
DTMC75-03-F-00087 |
12.
Sponsoring Agency Name and Address
Federal Motor Carrier Safety Administration
Office of Research and Analysis
400 Virginia Ave. SW
Washington, DC 20024 |
13.
Type of Report and Period Covered
Technical Report -
October 2003-July 2005 |
14. Sponsoring
Agency Code
FMCSA |
15.
Supplementary Notes
This program was administered through the Federal Motor Carrier
Safety Administration (FMCSA). The
FMCSA Program Manager is Mrs. Amy Houser. |
16.
Abstract
The Federal Motor
Carrier Safety Administration’s (FMCSA’s)
safety goal is to reduce the number and severity of large truck fatalities
and crashes. During the last several years,
FMCSA has collaborated with the trucking industry to test
and evaluate several on-board safety systems for commercial motor vehicles
to increase the safety and security of all roadway users.
FMCSA is now promoting voluntary adoption of these systems
within trucking fleets by initiating steps to work closely with the
trucking industry to define vendor-independent, voluntary requirements.
The purpose of
this document is to relay a better understanding of the functions of
on-board safety systems and to provide insight into the safety and efficiency
benefits of using the systems. The information has been developed in
collaboration with trucking industry stakeholders, including representatives
from manufacturers; insurance companies; commercial motor vehicle carriers;
drivers; and academia.
This document describes the
concept of operations and voluntary requirements for Automated Cruise
Control/Collision Warning Systems (ACC/CWS) for large trucks greater
than 10,000 pounds gross vehicle weight rating (GVWR). Concepts of operations
provide information about how each user interacts with these safety
systems and their operational conditions. Voluntary requirements describe
features and functions used to define the safety systems and their operational
functionality.
|
17.
Keywords
Automated Vehicle Control, Collision Warning Systems, Commercial Motor
Vehicles, Heavy Trucks, Safety Systems, Tractor-Trailers, Vehicle Stability
Systems |
18.
Distribution Statement
|
19. Security
Classif. (of this report)
Unclassified |
20. Security
Classif. (of this page)
Unclassified |
21. No.
of Pages
24 |
22. Price |
|
Form DOT F1700.7 (8-72) |
Reproduction of complete page authorized. |
SI* (MODERN
METRIC) CONVERSION FACTORS
APPROXIMATE
CONVERSIONS TO SI UNITS
Symbol |
When
You Know |
Multiply
By |
To
Find |
Symbol |
LENGTH |
In |
inches |
25.4 |
millimeters |
mm |
Ft |
feet |
0.305 |
meters |
m |
Yd |
yards |
0.914 |
meters |
m |
Mi |
miles |
1.61 |
kilometers |
km |
AREA |
in2 |
square inches |
645.2 |
square millimeters |
mm2 |
ft2 |
square feet |
0.093
|
square meters |
m2 |
yd2 |
square yards |
0.836 |
square meters |
m2 |
Ac |
acres |
0.405 |
hectares |
ha |
mi2 |
square miles |
2.59 |
square kilometers |
km2 |
VOLUME |
fl
oz |
fluid ounces |
29.57 |
milliliters |
ml |
Gal |
gallons |
3.785 |
liters |
l |
ft33 |
cubic feet |
0.028 |
cubic meters |
m3 |
yd3 |
cubic yards |
0.765 |
cubic meters |
m3 |
MASS |
Oz |
ounces |
28.35 |
grams |
g |
Lb |
pounds |
0.454 |
kilograms |
kg |
T |
short tons (2000 lbs) |
0.907 |
megagrams |
Mg |
TEMPERATURE
(exact) |
F
|
Fahrenheit |
5(F-32)/9 |
Celsius |
C |
|
temperature |
or (F-32)/1.8 |
temperature |
|
ILLUMINATION |
Fc |
foot-candles |
10.76 |
lux |
lx |
Fl
|
foot-Lamberts |
3.426 |
candela/m2 |
cd/m2 |
FORCE
and PRESSURE or STRESS |
Lbf |
pound-force |
4.45 |
newtons |
N |
Psi
|
pound-force per square inch |
6.89 |
kilopascals |
kPa |
|
APPROXIMATE
CONVERSIONS FROM SI UNITS
Symbol |
When
You Know |
Multiply
By |
To
Find |
Symbol |
LENGTH |
mm |
millimeters |
0.039 |
inches |
in |
m |
meters |
3.28 |
feet
|
ft |
m |
meters |
1.09 |
Yards |
yd |
km |
kilometers |
0.621 |
miles |
mi |
AREA |
mm2 |
square millimeters |
0.0016 |
square inches |
in2 |
m2 |
square meters |
10.764 |
square
feet |
ft2 |
m2 |
square meters |
1.195 |
square yards |
yd2 |
ha |
hectares |
2.47 |
acres |
ac |
km2 |
square kilometers |
0.386 |
square miles |
mi2 |
VOLUME |
ml |
milliliters |
0.034 |
fluid ounces |
fl oz |
l |
liters |
0.264 |
gallons |
gal |
m3 |
cubic meters |
35.71 |
cubic
feet |
ft3 |
m3 |
cubic
meters |
1.307 |
cubic yards |
yd3 |
MASS |
g |
grams |
0.035 |
ounces |
oz |
kg |
kilograms |
2.202 |
pounds |
lb |
Mg |
megagrams |
1.103 |
short
tons (2000 lbs) |
T |
TEMPERATURE
(exact) |
C
|
Celsius |
1.8
C + 32 |
Fahrenheit |
F |
|
temperature |
|
temperature |
|
ILLUMINATION |
lx |
lux |
0.0929 |
foot-candles |
fc |
cd/m2
|
candela/m2 |
0.2919 |
foot-Lamberts |
fl |
FORCE
and PRESSURE or STRESS |
N |
newtons |
0.225 |
pound-force |
lbf |
kPa
|
kilopascals |
0.145 |
pound-force
per square inch |
psi
|
|
* SI is the symbol for the
International System of Units. Appropriate rounding should be made to comply
with Section 4 of ASTM E380.
1. INTRODUCTION
The Federal Motor Carrier Safety Administration’s (FMCSA’s) safety
goal is to reduce the number and severity of large truck fatalities and crashes.
During the last several years, FMCSA has collaborated with the trucking industry
to test and evaluate several on-board safety systems for commercial motor vehicles
to increase the safety and security of all roadway users. FMCSA is now promoting
voluntary adoption of these systems within trucking fleets by initiating steps
to work closely with the trucking industry to define vendor-independent, voluntary
requirements for these systems.
The purpose of this document is to relay a better understanding of the functions
of on-board safety systems and to provide insight into the safety and efficiency
benefits of using the systems. The information has been developed in collaboration
with expert panels consisting of trucking industry stakeholders, including representatives
from manufacturers, insurance companies, commercial motor vehicle carriers,
drivers, and academia.
This document describes the concept of operations and voluntary requirements
for Forward Collision Warning Systems (CWS) and Adaptive Cruise Control (ACC)
systems for large trucks greater than 10,000 pounds gross vehicle weight rating
(GVWR). Concepts of operations provide information about how each user interacts
with these safety systems and their operational conditions. Voluntary requirements
describe features and functions used to define the safety systems and their
operational functionality.
This document discusses CWS
and ACC systems provided by manufacturers, such
as:
- Delphi Electronics and Safety
- Eaton VORAD
- Mobileye
Descriptions of these currently available systems are in Appendix A. United
States Department of Transportation (USDOT) websites that contain further information
on governmental research, testing and evaluation of CWS
and ACC systems include:
www.its.dot.gov/ivi/ivi.htm
www.fmcsa.dot.gov/safetyprogs/research/researchpubs.htm
2. CONCEPT OF OPERATIONS
Description
- Forward Collision Warning Systems
CWS are in-vehicle electronic systems that monitor the roadway
in front of the host vehicle and warn the driver when a potential collision
risk exists. For example, currently available radar-based CWS
use algorithms to interpret transmitted and received radar signals to determine
distance, azimuth, and relative speed between the host vehicle with the CWS
and the vehicle or object ahead of it in the lane. When the host vehicle is
traveling along the roadway, the CWS can warn the driver
when a vehicle or object is in its lane within a predefined closing time threshold.
Currently, CWS do not take any automatic action to avoid
a collision or to control the vehicle; therefore, drivers remain responsible
for the safe operation of their vehicles using both steering and braking, if
safe to do so, to avoid a crash. As the time interval to the vehicle ahead decreases,
CWS issue a progressively more urgent warning. The system’s
beam width/field of view forms an isosceles triangle with its apex at the front
center of the vehicle. As an object gets closer to the front of the vehicle,
a different range or time interval is reached, and the system issues a different
type of alarm. The system manufacturers set these warning thresholds. Figure
1 illustrates these progressive thresholds. CWS also warn
the driver if the system malfunctions. CWS may be integrated
with ACC systems.
Figure 1
CWS Object Detection Ranges and Collision Warning Thresholds
Description
- Adaptive Cruise Control Systems
ACC systems are in-vehicle electronic systems that automatically
maintain a minimum following interval to a lead vehicle in the same lane. The
ACC system utilizes components of the collision warning system
and a conventional cruise control system. When the host vehicle with the ACC
system is traveling above a minimum speed threshold, the ACC
system controls the engine throttle, and if available, engine brake and automatic
transmission to maintain the following interval. The driver can set and adjust
his following interval. In the absence of a vehicle ahead, the ACC
system operates like a conventional cruise control by maintaining the speed
set by the driver. The ACC system will notify the driver
if the system detects a malfunction. Figure 2 illustrates the general thresholds
used by an ACC system. The system's beam width/field of
view forms an isosceles triangle with its apex at the front center of the vehicle.
It graphically displays minimum and maximum following distance or time intervals
in which the system operates.
Although ACC systems automatically take action
to control the vehicle’s speed, they may not sufficiently decelerate the
vehicle in all circumstances to avoid a crash. Depending on the vehicle load,
road grade, and vehicle performance parameters, the level of deceleration control
typically used by the system is limited to a range between 0.1 and 0.2 g, where
g is a unit of force equal to the force exerted by gravity. As a result, drivers
remain responsible for the safe operation of their vehicles, and they should
use steering and apply the service brakes, if safe to do so, to avoid a crash.
Figure 2
ACC System Vehicle Following Intervals
Crash Prevention
CWS and ACC systems can help reduce crashes when vehicles are equipped with
these systems. In particular, these systems may prevent rear-end crashes and
forward impact crashes with objects in the travel lane. These systems may also
reduce the impact speed and the crash severity. This section describes these
crash types.
- Rear-end Crash – Rear-end crashes occur when the
front of a following vehicle strikes the rear of a lead vehicle. Data derived
from the 2003 General Estimates System[1]
(GES) indicates that 42,800
rear-end crashes involving large trucks occurred in 2003, resulting in 290
fatalities. “In 18 percent of all rear-end crashes where the truck was
the striking vehicle, there were three or more vehicles involved in the crash.
The difference is even greater in fatal rear-end crashes. Almost 46 percent
of fatal rear-end truck-striking crashes involved three or more vehicles,
while only 16 percent of fatal truck-struck rear-end crashes involved three
or more vehicles. The large difference between the mass of trucks and the
mass of other vehicles may explain this phenomenon. A typical loaded tractor
semi-trailer has a gross weight of 80,000 pounds, while most cars weigh less
than 4,000 pounds. Striking a passenger vehicle in the rear will not bring
a heavy truck to a stop or even slow it appreciably. Thus, the impact itself
does relatively little to keep the truck from continuing on and involving
other vehicles.”[2]
CWS can reduce the risk of these rear-end crashes by identifying
fast closing situations and providing the driver with additional time to react.
ACC systems function to maintain a driver-set following
interval behind another vehicle, thereby providing more time to resolve driving
conflicts to reduce the probability of a rear-end collision.
- Forward Impact with Objects in Travel Lanes – These
crashes occur when a vehicle strikes an object that is in the vehicle’s
travel lane. Data from the 2003
GES indicates that large trucks were involved in 18,000 crashes
of this type in 2003, resulting in 160 fatalities. CWS
can reduce the risk of these crashes by warning the driver of the presence
of these objects, thereby allowing them additional time to take the appropriate
avoidance maneuvers.
Additional benefits of ACC systems and CWS may include the reduction of hard
braking events.
Operations
and Users
This section describes how drivers, fleet managers, and fleet maintenance personnel
interact with CWS and ACC systems and potential benefits that each stakeholder
may realize with these systems.
The commercial vehicle population is comprised of a wide variety of vehicle
types and uses. At a high level, two types of vehicles are predominant, combination
vehicles (tractors-trailers) and straight trucks. These two types of vehicles
have very different operating characteristics. In general, straight trucks tend
to be used in a more local setting, used to provide deliveries of goods and
services to customers generally within a 50 to 100 mile radius of their base
of operations, while combination vehicles are more often utilized in regional
and long distance applications. Combination vehicles account for about 30% of
total commercial vehicles, but 65% of the commercial vehicle miles traveled.
Due to their high mileage exposure and severity of crashes, combination-unit
trucks have the highest crash cost per vehicle over the operational life of
the vehicle.[3]
Therefore, CWS may provide a relatively higher safety benefit
for operators of this class of trucks.
The trucking industry is actually a broad collection of many industries, each
with operating characteristics as diverse as the industries they service. Segmentation
of the trucking industry is often based on the size of fleets, the geographic
range of its operations, and the commodities hauled. Usually one characteristic
is not adequate to describe a particular segment, but rather combinations of
characteristics are required to best describe operations. For example, there
may be a trucking firm with a large fleet providing package delivery type service
to a relatively small geographic area, while there may be a single truck company
that provides general freight services to all states in the continental United
States.
The movement of goods by truck is conducted on all types of roads, at all hours
of the day, and in all types of driving conditions. Since collisions with other
vehicles or obstacles can occur along any route, many fleet types may benefit
from using CWS, yet they may be most promising for trucks with high mileage
accumulated over their operational life or that operate under conditions that
may present driving challenges such as nighttime or limited visibility due to
weather. Also, currently, CWS operate at any vehicle speed. ACC systems only
operate above a specified minimum vehicle speed, which typically limits the
systems’ use to roadways where drivers travel at or above this minimum
speed in accordance with the posted speed limits. The application of these systems
to specific fleets may be determined by the amount of time the fleet’s
vehicles operate in these roadway types.
Drivers
Drivers are the primary CWS and ACC system users, as described in the following
daily operational scenarios:
Normal system startup operation – When the driver
turns the ignition switch to start the vehicle, CWS and
ACC systems perform a power-up self-test. The driver scans
the warning indicators to determine any system malfunctions. If necessary,
the driver may alert fleet maintenance personnel for corrective action. A
driver can scan the CWS
or ACC system status indicator to verify that the system
operation has commenced.
System fault conditions – If a system fault occurs
or the system cannot detect vehicles ahead or control the speed of the host
vehicle, the driver is provided with a message via the system status indicator.
Some CWS and ACC systems may display warning indicators relating to specific
faults or other detected conditions.
Progressive CWS warning/alert situations
– When traveling at or above the minimum CWS detection
speed, the host vehicle will encounter other vehicles ahead within the travel
lane. As the host vehicle approaches the vehicle ahead, the CWS
may provide a series of progressive alerts to the driver. These progressive
alerts indicate that the following interval is decreasing and the driver should
take action. These progressive warnings can escalate from audio tone only
to audio, visual, or other warning modes.
ACC system operation – ACC systems automatically maintain
a minimum following interval between the driver’s vehicle and the vehicle
ahead of it. When no vehicle is present in front of the vehicle with the ACC
system, the ACC system maintains the speed set by the driver as in current
cruise controls. The system has a self-diagnosis mode that can detect system
faults. If the system is active when a fault is detected, the ACC system reverts
to manual throttle control.
On-road use of CWS and ACC systems – A driver may
encounter several types of roadways where these systems provide a potential
benefit. Yet, some systems may have limitations, including false positive
indications, such as the identification of signs, barrels, and other roadside
objects that may not be actual obstacles in the travel lane.
Divided highways and interstates/Straight and large radius curved
flat roads – “Trucks Involved in Fatal
Accidents (TIFA) and
GES data show that rear-end truck crashes are more likely to occur
on divided roadways and interstate highways–overlapping categories–than
other truck crashes. With regard to fatal crashes, 58 percent of truck striking
crashes occurred on interstate highways, as opposed to 19 percent of all
truck fatal crashes.[4]"
These road types are where CWS and ACC
systems could provide the greatest benefit. While the vehicle is operating
on these roads, CWS can detect vehicles ahead and issue
warnings to the driver when it detects an excessive closing speed condition.
ACC systems will control the speed of the host vehicle
and interval to the lead vehicle.
Two-way roads with sharp curves – CWS
and ACC systems could have limited azimuthal coverage
to the front of the vehicle. When the host vehicle is traversing sharp curves,
the lead vehicles may no longer be in the range of the host vehicle’s
sensor coverage area. When these situations arise, each system has a different
means of accommodating the loss of detecting the lead vehicle. CWS
may not re-detect the lead vehicle until the host vehicle enters the curve.
The ACC system will revert to conventional cruise control
by maintaining the current set speed until the lead vehicle is detected
again. When the lead vehicle is detected, the ACC system
will revert to the set following interval.
Roads with hills and valleys – CWS may produce false
positive indications when the host vehicle is on a roadway with major changes
in elevation. When a host vehicle is traveling up a hill, current CWS may
detect objects such as overhead signs. Other roadway features that could
cause loss of vehicle tracking or false alarms include dips in the roadway
and hillcrests.
Fleet Management
Fleet managers are responsible for all administrative, financial, and operational
aspects of the fleet. Safety officers focus on the fleet’s operational
safety issues and examine the safety aspects of the fleet’s vehicles in
accordance with USDOT
safety regulations. They also work with drivers to provide
safety and operational training, verify that drivers are complying with safety
regulations, and examine how well drivers operate their vehicles (e.g., logging
accidents, traffic infractions, etc.).
These personnel examine various types of available safety equipment, evaluate
the equipment, justify the purchase of all equipment, determine the overall
effectiveness of this equipment, and calculate the return on investment (ROI)
for their fleet. They work with the maintenance department and drivers to explain
CWS and ACC system benefits. CWS and ACC systems may have the capability to
store operational data internally for retrieval by the fleet. This data may
be useful in reconstructing an accident or as training feedback in analyzing
a driver’s performance. Fleet managers may obtain operational data (e.g.,
number of hard-braking events) from CWS and ACC systems via the in-vehicle network
and analyze the data to determine any systemic problems with their fleet operations
(e.g., disproportionate number of close-following events with certain drivers,
high number of hard-braking events on certain routes). These in-vehicle networks
provide a data “backbone” to the truck, permitting the sharing of
various system level data, such as engine and transmission performance. Research
has indicated that the monitoring of driver behavior can have a positive effect
on driver and fleet safety.[5]
Maintenance
Management and Installation
Maintenance managers and service technicians are responsible for the proper
functioning of all equipment installed on the fleet’s vehicles and for
installing and maintaining CWS and ACC systems on the fleet. The maintenance
managers support fleet operations by maintaining CWS and ACC systems. They acquire
and relay operational and reliability data to the fleet managers and work with
suppliers to resolve any problems encountered with system use.
CWS and ACC systems have different installation
requirements for each vehicle type and model. Depending on the system, CWS
and ACC systems may be installed by a truck
original equipment manufacturer (OEM) or as an aftermarket accessory
by the fleet or other service personnel. When installed by a truck
OEM, the CWS and ACC system
component locations and mounting methods are identical for each vehicle model.
The OEM provides
dedicated wiring harnesses for the connection between the CWS
and ACC systems and the vehicle. When installed as an aftermarket
accessory, CWS and ACC systems’
components should be in the proper locations and orientations as described in
the installation manual with the key parameters entered into the system. Furthermore,
the systems will require periodic maintenance, particularly in the area of component
(e.g., radar, camera, antennae) alignment.
3. VOLUNTARY REQUIREMENTS
The voluntary requirements included in the following sections define fundamental
CWS and ACC system features and the ability of the systems to withstand the
electrical and environmental extremes commonly found on commercial vehicles.
The types of voluntary requirements for CWS include:
- Functional Requirements
- Data
- Hardware and Software Requirements
- Driver Vehicle Interface (DVI) Requirements
- Maintenance and Support Requirements
CWS and ACC system manufacturers may
include additional functions to augment system capability and features that
may be useful beyond minimum system functionality; the operational features
that fall into this category are labeled with the term “OPTIONAL”.
However, in all cases, CWS and ACC systems
must comply with all existing
FMCSA Safety Regulations. The requirements numbering system designates
defining requirements with an “R” and optional features with a “T”.
3.1 Functional
Requirements
Functional requirements refer to basic system functionality and operation of
CWS
and ACC systems.
R1-1 |
CWS and ACC systems
should perform a self-test that checks all major system sensors and components
and operate within 30 seconds of starting the vehicle. System status results
should be provided to the driver within the 30 seconds time interval.
|
R1-2 |
CWS should detect, track, and issue warnings for
the following potential pre-collision conditions based on following interval
thresholds when the functional requirements R1-3 and R1-4 are met:
- Host vehicle closing on a lead vehicle with constant velocity
- Host vehicle closing on a lead vehicle that is accelerating
- Host vehicle closing on a lead vehicle with both vehicles decelerating
- Host vehicle closing on a lead vehicle preceded by a lane change
- Host vehicle closing on a stopped lead vehicle
- Host vehicle closing at a constant speed on a decelerating lead vehicle
- Host vehicle closing on a stationary object in the roadway
|
R1-3 |
CWS and ACC systems should be capable
of detecting a vehicle in the travel lane of the vehicles with the CWS
and ACC systems to a distance of up to 100 meters (328
feet) on straight roads and on curves with radius greater than 500 meters
(1640 feet).
|
R1-4 |
CWS
and ACC systems should be capable of differentiating between oncoming
traffic on two-way curved roadways and vehicles in the travel lane of the
vehicles with the CWS
and ACC systems.
|
R1-5 |
CWS and ACC systems should function
under all potential weather conditions such as clear weather, rain, snow,
fog, or combinations of these conditions. If the system cannot function
in these conditions, the driver should be provided with a clear indication
that the system is not functioning.
|
R1-6 |
CWS
and ACC systems should be capable of differentiating stationary roadside
objects such as guardrails, signs, and bridges from moving vehicles in both
the travel lane and opposing lanes of the vehicles with the CWS
and ACC
systems.
|
R1-7 |
If CWS
and ACC systems engage the vehicle’s service brakes, the
vehicles brake lights should be activated in compliance with Federal Motor
Vehicle Safety Standard 108.
|
R1-8 |
CWS
should use progressive warnings to provide the driver with sufficient
time to avoid forward crashes.
|
T1-1 |
OPTIONAL – CWS
may interact with an ACC system
to maintain a safe following interval to the vehicle ahead.
|
T1-2 |
OPTIONAL – CWS
may issue proximity warnings when
the host vehicle is slowly moving forward (less than 2 mph) towards a stationary
object or if an object ahead is slowly rolling towards the front of the
host vehicle.
|
3.2 Data
This section defines the format of data generated by or can be obtained directly
in real-time from CWS and ACC systems. Two Society of Automotive Engineers (SAE)
standards specify in-vehicle data communication in heavy trucks:
- SAE J1587, “Electronic Data Interchange between Microcomputer Systems
in Heavy-Duty Vehicle Applications” (message definition for the J1708
data bus), or
- SAE J1939-71, “Recommended Practice for Control and Communications
Network for On-Highway Equipment – Vehicle Application Layer”
Although neither of these standards defines CWS messages,
it would be beneficial if CWS suppliers adopt a common set
of standard CWS messages. Drivers and fleet managers could
obtain these CWS messages via the in-vehicle data network.
SAE J1939-71 already defines the data available from ACC
systems via the on-board diagnostic (OBD) connector.
T2-1 |
OPTIONAL – ACC systems may issue various
data messages about the operating states and modes of the system on the
in-vehicle data network, which may be custom messages or as defined by SAE
standard J1939.[6]
|
T2-2 |
OPTIONAL – CWS
and ACC systems may have the capability
to store operational data for providing driving feedback to drivers. |
3.3 Hardware and
Software Requirements
Hardware and software requirements deal directly with the detailed functionality
of the hardware, environmental and electrical concerns, mounting/installation
issues, and software design. Figures 3 and 4 illustrate the major functional
components and interfaces of CWS and ACC systems as described in the following
sections, respectively. Figure 3 shows the inter-relationship of the CWS components.
The electronic control unit (ECU) accepts data from the forward-looking sensor.
Through the vehicle network (J1708 or J1939), the ECU monitors the brake activation
status and engine power. The output of the system is a status indicator and,
when necessary, a warning, which appear on the driver-vehicle interface. Figure
4 shows the inter-relationship of the ACC system components. The ECU has the
same input and outputs as in a CWS, but it has the additional capability to
control the engine speed or to shift the automatic transmission. Both figures
show that the CWS and ACC are often integrated into a single system.
Figure 3
CWS
Major Functional Components
Figure 4
ACC System Major Functional Components
Typical System
Hardware
This section describes the functionality of the primary physical components
of CWS and ACC systems. They refer to the functional blocks shown in Figures
3 and 4.
R3-1 |
Forward-looking Sensor or Detector –
CWS and ACC systems should have a
sensor or apparatus that detects vehicles in the front of the host vehicle.
This sensor or apparatus should be capable of determining the distance and
location of moving or stationary vehicles in the travel lane of the host
vehicle. CWS and ACC systems should
be capable of detecting moving or stationary vehicles to at least 100 meters
(328 feet) ahead of the vehicle. |
R3-4 |
Electronic Control Unit (ECU) – The CWS
and ACC systems’ ECU
should be used to gather data for calculating key parameters to provide
warnings. For the ACC system, the ECU
should be capable of controlling the engine speed or shifting the automatic
transmission. |
R3-2 |
Driver Vehicle Interface – CWS and ACC systems
should provide a driver vehicle interface (DVI) to permit the driver to
interact with the systems. A DVI consists of controls and indicators for
CWS and ACC systems related to the system operation. The DVI includes progressive
audible and visual warnings of a potential collision threat to the host
vehicle. CWS and ACC systems should provide a visual indication of the status
of the systems. System status includes operational/non-operational, tracking/not-tracking,
and system fault conditions. See Section 3.4 for complete DVI requirements. |
T3-1 |
OPTIONAL – Adaptive Cruise Control
– CWS may interact with an ACC
system to maintain a safe following interval between the host vehicle and
the vehicle in front of it. |
T3-2 |
OPTIONAL – Vehicle Network –
CWS and ACC systems may use the in-vehicle
data network (SAE J1708 or J1939) for data communication
to data recording or diagnostic devices.
|
Environmental
Requirements
The environmental conditions that exist in heavy trucks are very severe. The
SAE has developed a comprehensive standard that describes various aspects of
the heavy truck environment in its J1455 standard. The standard also includes
procedures that are used to verify system compliance.
R3-3 |
CWS and ACC systems should meet the environmental requirements
as stated in the most recent version of the following SAE standard:
|
|
SAE Standard J1455, “Joint SAE/
Technology and Maintenance Council (TMC) Recommended Environmental
Practices for Electronic Equipment Design (Heavy-Duty Trucks)”.
|
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The following environmental aspects are covered by the standard: |
|
- Altitude
- Fungus
- Mechanical Shock
- Mechanical Vibration
- Relative Humidity
|
- Temperature
- Salt Spray Atmosphere
- Immersion and Splash
- Steam Cleaning and Pressure Washing
- Dust, Sand, and Gravel Bombardment
|
Electrical
Requirements
In a truck’s electrical power distribution system, the system voltage
may vary, the alternator may generate electrical noise, and various types of
transients may momentarily place more than 100 volts direct current (VDC)
on the electrical distribution system’s wiring. In addition, there may
be electrostatic discharge into the system from a buildup of static electricity.
Because CWS and ACC systems connect to
the truck’s electrical power distribution system, they should function
normally throughout all of these perturbations without damage.
R3-4 |
CWS
and ACC system power should be derived from the vehicle
electrical system.
|
R3-5 |
CWS and ACC systems should meet
the electrical requirements as stated in most current version of the following
SAE standards:
SAE Standard J1455, “Joint SAE/ TMC Recommended Environmental
Practices for Electronic Equipment Design (Heavy-Duty Trucks)”.
SAE Standard J1113, “Electromagnetic Compatibility Measurement
Procedures and Limits for Vehicle Components (Except Aircraft) (60 Hz
to 18 GHz)”.
The following environmental aspects are covered by the standards:
- Steady State Electrical Characteristics
- Transient Electrical Characteristics
- Electromagnetic Susceptibility
- Electromagnetic Emission
|
R3-6 |
CWS
and ACC system data should not be destroyed nor corrupted during a
power surge.
|
Mounting and
Installation Requirements
Mounting and installation requirements include all aspects related to the installation
of CWS
and ACC system hardware onto the truck, including the mounting of the
individual system components. There are no specific requirements pertaining
to system size or weight.
R3-7 |
CWS
and ACC systems should be installed per manufacturer’s
recommendations.
|
R3-8 |
Major CWS
and ACC system components, other than cabling or small mounting
components, should be marked with the manufacturer’s identification.
|
Software Requirements
Software requirements refer to the embedded software that runs in CWS
and ACC
systems and controls all system functionality. The microcontroller or microprocessor
continuously runs the system software when CWS
and ACC systems are active.
T3-3 |
OPTIONAL – CWS
and ACC systems may
include software for downloading ASCII data files that can be easily read
into a statistical, database, or spreadsheet software package.
|
T3-4 |
OPTIONAL – The embedded software of CWS
and
ACC systems can be field upgradeable via the in-vehicle network connection
(i.e., J1587 or J1939) or other common data interface (e.g., RS-232 or
Universal Serial Bus (USB)). Only authorized personnel should upgrade
embedded software.
|
3.4 Driver-Vehicle
Interface Requirements
These requirements define specific ways in which CWS and
ACC systems interface with the driver (i.e., Driver-Vehicle
Interface), and include indicators, displays, and warning methods. The National
Highway Traffic Safety Administration (NHTSA) Federal Motor
Vehicle Safety Standard 101 (FMVSS 101) should be used as
a guide for CWS and ACC system indicators.
R4-1 |
CWS should utilize different audible
tones (e.g., different pitches, patterns, lengths, etc.) or tactile warnings
to provide multiple warnings as an object crosses the warning thresholds.
|
R4-2 |
CWS and ACC systems should include
a visual indicator when no vehicles or objects are in the lane. The indication
may be provided by an instrument panel warning light or an indicator that
is integral to each system.
|
R4-3 |
CWS and ACC systems should use a visual indicator to provide system operational
status. This status may be indicated by an instrument panel warning light
or an indicator that is integral to each system.
|
R4-4 |
CWS and ACC systems should use a visual or audible indicator to indicate
a system failure or malfunction. This status may be indicated by an instrument
panel warning light or an indicator that is integral to the system.
|
R4-5 |
CWS and ACC system indicators should be clearly discernable in direct
sunlight and at night.
|
T4-1 |
OPTIONAL – CWS should utilize combinations of audible,
visual and tactile indicators to provide multiple warnings of object detection
and impending collision.
|
T4-2 |
OPTIONAL – CWS may allow the volume of the audible
warnings to be adjusted, but not below a minimum sound level of 65 dBA .[7]
|
T4-3 |
OPTIONAL – CWS and ACC systems
may provide operational or diagnostic messages or codes, such as “System
Operational” on an alphanumeric display to alert the driver of specific
faults, conditions, or concerns.
|
3.5 Maintenance
and Support Requirements
Maintenance and support requirements include functionality/features that should
be provided to ensure CWS
and ACC systems will be operated correctly and properly
maintained.
R5-1 |
CWS and ACC systems
should be serviced periodically in accordance with system maintenance
instructions to maintain system functionality. This process maintains
the proper alignment and calibration of integral CWS
and ACC system components, such as the radar sensor,
camera, and antennae. |
R5-2 |
Users should be provided with a manual and training for CWS
and ACC systems. |
R5-3 |
At a minimum, the user’s manual should include information on the
minimum vehicle speed at which CWS
and ACC systems operate, the conditions
under which the systems can/cannot detect and track vehicles, and the types
of indicators used to inform the driver if the systems are functioning properly.
|
R5-4 |
Manufacturers should provide product support for users and fleets to ask
questions regarding capabilities and resolve problems with systems.
|
T5-1 |
OPTIONAL – Video, audio, or computer-based training
material may be provided for fleet management and/or drivers.
|
T5-2 |
OPTIONAL – CWS
and ACC systems may be transferable
from one vehicle to another. System recalibration and/or resetting of system
parameters should be performed when the system(s) are moved between vehicles.
|
4. ACRONYMS
Acronym |
Definition |
ACC |
Adaptive Cruise Control |
ASCII |
American Standard Code for Information Exchange |
COTS |
Commercial Off-The-Shelf |
CWS |
(Forward) Collision Warning System(s) |
DVI |
Driver-Vehicle Interface |
ECU |
Electronic Control Unit |
EV |
Eaton VORAD |
FMCSA |
Federal Motor Carrier Safety Administration |
FMVSS |
Federal Motor Vehicle Safety Standard |
GES |
General Estimates Systems |
GVWR |
Gross Vehicle Weight Rating |
kph |
Kilometers per Hour |
mph |
Miles per Hour |
NHTSA |
National Highway Traffic Safety Administration |
OBD |
On-Board Diagnostic |
OEM |
Original Equipment Manufacturer |
ROI |
Return on Investment |
SAE |
Society of Automotive Engineers |
TIFA |
Trucks Involved in Fatal Accidents |
TMC |
Technology and Maintenance Council |
USB |
Universal Serial Bus |
USDOT |
United States Department of Transportation |
VDC |
Volts Direct Current |
5. REFERENCES
[1]The General Estimates System is directed
by the National Center for Statistics and Analysis, which is a component of
The Office of Research and Development in
NHTSA. Data for GES
come from a nationally representative sample of police reported motor vehicle
crashes of all types, from minor to fatal. The system began operation in 1988,
and was created to identify traffic safety problem areas, provide a basis for
regulatory and consumer initiatives, and form the basis for cost and benefit
analyses of traffic safety initiatives. The information is used to estimate
how many motor vehicle crashes of different kinds take place, and what happens
when they occur.
[return to report]
[2]Craft, Ralph.
FMCSA Paper: Rear-End Large Truck Crashes, 2002.
[return to report]
[3]Wang, J.S.; Knipling, R.R.; and Blincoe,
L.J. The dimensions of motor vehicle crash risk. Journal of Transportation and
Statistics. Volume 2, No. 1, pp. 19-43, ISSN 1094-8848, May 1999.
[return to report]
[4]Craft, Ralph.
FMCSA Paper Rear-End Large Truck Crashes.
[return to report]
[5]Knipling, R.R.; Boyle, L.N.; Hickman,
J.S.; York, J.S.; Daecher, C.; Olson, E.C.B.; and Prailey, T.D. Synthesis
Report No. 4: Individual Differences and the High-Risk
Commercial Driver. Project Final Report, Transportation Research Board
Commercial Truck and Bus Synthesis Program. ISSN 1544-6808,
ISSN 0-309-08810-0, available at http://trb.org/news/blurb_browse.asp?id=11,
2004
[return to report]
[6]Heavy trucks may have either or both J1708
and J1939 networks. J1708 (J1587) is typically more easily accessible by the
fleet, and J1939 is typically reserved for high-priority engine-transmission
control data. However, CWS may interface with either or both networks. See Section
4.4 for a listing of CWS’ network messages.
[return to report]
[7]For reference: 90 dBA = heavy truck at
10m, 80 dBA = curbside of busy street, 70 dBA = car interior, 60 dBA = normal
conversation at 1m (3.28 feet), and 50 dBA = office noise.
[return to report]
Craft, Ralph.
FMCSA Paper Rear-End Large Truck Crashes. http://www.fmcsa.dot.gov/facts-research/briefs/rear.pdf,
2002.
SAE Standard J1113, “Electromagnetic Compatibility Measurement Procedures
and Limits for Vehicle Components (Except Aircraft) (60 Hz to 18 GHz),”
July 1995.
SAE Standard J1455,
“Joint SAE/TMC
Recommended Environmental Practices for Electronic Equipment Design (Heavy-Duty
Trucks),” August 1994.
SAE Standard J1587, “Electronic Data Interchange between Microcomputer
Systems in Heavy-Duty Vehicle Applications,” February 2002.
SAE Standard J1708, “Serial Data Communications between Microcomputer
Systems,” October 1993.
SAE Standard J1939-71, “Recommended Practice for Control and Communications
Network for On-Highway Equipment – Vehicle Application Layer,” September
2002.
Wang, J.S.; Knipling, R.R.; and Blincoe, L.J. The dimensions of motor vehicle
crash risk. Journal of Transportation and Statistics. Volume 2, No. 1, pp. 19-43,
ISSN 1094-8848, May 1999.
Wierwille, W.W.; Lewin, M.G.; and Fairbanks, R.J. III.
Final Report: Research on Vehicle-Based Driver Status/Performance Monitoring;
Part I. Vehicle Analysis and Simulation Laboratory,
Virginia Polytechnic Institute and State University, Publication No.
DOT HS 808 638, September 1996.
Wierwille, W.W.; Lewin, M.G.; and Fairbanks, R.J. III. Final Report: Research
on Vehicle-Based Driver Status/Performance Monitoring; Part II. Vehicle Analysis
and Simulation Laboratory, Virginia Polytechnic Institute and State University,
Publication No. DOT
HS 808 638, September 1996.
Wierwille, W.W.; Lewin, M.G.; and Fairbanks, R.J. III. Final Report: Research
on Vehicle-Based Driver Status/Performance Monitoring; Part III. Vehicle Analysis
and Simulation Laboratory, Virginia Polytechnic Institute and State University,
Publication No. DOT
HS 808 638, September 1996.
A. APPENDIX A –
COMMERCIAL OFF-THE-SHELF CWS AND ACC SYSTEMS
The following Commercial Off-the-Shelf (COTS) CWS
are currently available
Delphi Electronics and Safety (www.delphi.com)
– Delphi is developing CWS for commercial vehicles.
The CWS uses a radar sensor to detect slower moving vehicles
in-lane at a range of up to 80 meters on straight roads and curves of constant
radius greater than 500 meters. The system provides a warning in sufficient
time to avoid a collision when the following interval is a minimum of 2 seconds.
The system does not feature side or rear-object detection or an interface
to an ACC system.
Eaton VORAD (EV) (www.roadranger.com/VORAD)
– The EV EVT-300 CWS
is part of a larger system including ACC, side object detection,
and trip/accident reconstruction data recording. The
EV CWS uses a front bumper mounted radar sensor
and an in-vehicle processor to detect and provide warnings of vehicles within
the same lane up to 150 meters (500 feet) ahead. To permit detection around
curves, a yaw gyro provides road curvature estimates. A driver display unit,
which contains the audible and visual warning devices, enables driver adjustment
of some of the system’s operating characteristics.
Mobileye (www.mobileye.com)
– The “Mobileye Advanced Warning System” is a camera-based
system that includes a small camera and a processing unit mounted to the upper
center of the windshield and a cell phone-sized alphanumeric/graphic driver
display on the dashboard. Two in-cab speakers, one on either side of the vehicle,
provide audible warnings with adjustable volume control. When lane markings
are not visible due to dense fog, heavy rain or snow, roads covered with mud,
ice, or snow; the systems notify the driver and shut down. This system is
available as a stand-alone system or as an additional feature in a more extensive
system including lane departure warning, headway indication and warning, and
cut-in warning and lane change assist features.
The following COTS ACC systems will be available currently or in the near future:
Delphi Electronics and Safety (www.delphi.com)
– Delphi is developing ACC systems for commercial
vehicles. The radar-based systems detect vehicles in-lane at a range of up
to 80 meters on straight roads and curves of constant radius greater than
500 meters.
Eaton VORAD (EV) (www.roadranger.com/VORAD)
– The EV “SmartCruise”
ACC system is an optional part of a larger system including
CWS, side object detection, and trip/accident reconstruction
data recording. The EV ACC
system uses radar to detect vehicles up to 500 feet ahead. To permit detection
around curves, a yaw gyro provides road curvature estimates. A driver display
unit enables driver adjustment of the system’s operating characteristics.
Mobileye (www.mobileye.com)
– The “Mobileye Advanced Warning System” includes a small
camera and a processing unit mounted to the windshield behind the rear-view
mirror and a cell phone-sized alphanumeric/graphic driver display on the dashboard.
The system detects and tracks vehicles ahead of the host vehicle, monitors
the distance and following time interval to them, and issues commands to the
vehicle’s cruise control system to maintain a safe following interval.
The following interval is adjustable. It is available as a stand-alone system
or as an additional feature in a more extensive system including lane departure
warning, forward collision warning, headway indication and warning, cut-in
warning, and lane change assist features.
Summary of CWS
COTS System Features
Table A-1 provides comparative information relative to the features of each
of the COTS systems described in this appendix. Each manufacturer provided this
information.
Table A-1
Summary of COTS CWS Features
Feature |
Delphi |
|
Mobileye |
Detects obstacles,
moving and fixed |
Yes |
Yes |
Yes |
Operates on straight
and curved roads |
Yes |
Yes |
Yes |
Detects closing rate
and alerts driver above a threshold |
Yes |
Yes |
Yes |
Tracks multiple vehicles
and objects |
Yes |
Yes |
Yes |
Uses audible and visual
collision warnings |
* |
Yes |
Yes |
Uses progressive alert
levels |
No |
Yes |
Yes |
Permits adjustment
of warning threshold location |
* |
Yes |
Yes |
Permits adjustment
of audible warning volume |
* |
Yes |
Yes |
Permits temporary
disabling of detection |
* |
Yes |
No |
Has visual tracking
indicator |
* |
Yes |
Yes |
Has visual system
status indicator |
* |
Yes |
Yes |
Has audible or visual
system failure indicator |
* |
Yes |
Yes |
Provides a Driver
Interface Unit |
* |
Yes |
Yes |
Has a proximity alert
|
* |
Yes |
No |
Interfaces to ACC
System |
* |
Yes |
Yes |
Logs data internally
|
No |
Yes |
Yes |
Data messages available
|
* |
Yes |
No |
Data link used |
* |
J-1587/
J-1939 |
Ethernet
or
USB 2.0 |
Aftermarket installation
by fleets possible |
* |
Yes |
Yes |
* As of release of
this document, details for this feature have not been determined.
Summary of ACC
COTS System Features
Table A-2 provides comparative information relative to the features of each
of the COTS systems described in this appendix. Each manufacturer provided this
information.
Table A-2
Summary of COTS ACC System Features
Feature |
Delphi |
|
Mobileye |
Operates on straight
and curved roads |
Yes |
Yes |
Yes |
Tracks multiple objects
|
Yes |
Yes |
Yes |
Provides a Driver
Interface Unit |
* |
Yes |
Yes |
Has system status
indicator |
* |
Yes |
Yes |
Displays range and
following interval to vehicle ahead |
* |
No |
Yes |
Permits adjustment
of following interval |
* |
Yes |
Yes |
Interfaces to CWS
|
* |
Yes |
Yes |
Logs data internally
|
No |
Yes |
No |
Data messages available
|
* |
Yes |
Yes |
Data link used |
* |
J-1587/
J-1939 |
|
Aftermarket installation
by fleets possible |
* |
Yes |
Yes |
* As of
release of this document, details for this feature have not been determined.
Report
No. FMCSA-MCRR-05-007 |
For
more information on the Federal Motor Carrier Safety Administration
and the Office of Research and Analysis, check out our website at (www.fmcsa.dot.gov)
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