Advanced Lane Management Assist (ALMA)
for Partially and Fully Automated Vehicles
Robert L. Gordon, P.E.
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Purpose of ALMA
In connection with limited access highways ALMA* assists
conventionally driven vehicles as well as partially and fully
automated vehicles to provide decision support for lane
selection and target speed for the selected lane.
*Patent pending
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Automated Vehicle Classification Scheme
•
No-Automation (Level 0): The driver is in complete and sole control of the primary vehicle controls
– brake, steering, throttle, and motive power – at all times.
•
Function-specific Automation (Level 1): Automation at this level involves one or more specific
control functions. Examples of single functions include adaptive cruise control and lane centering.
•
Combined Function Automation (Level 2): This level involves automation of at least two primary
control functions such as those described under Level 1 designed to work in unison to relieve the
driver of control of those functions.
•
Limited Self-Driving Automation (Level 3): Vehicles at this level of automation enable the driver to
cede full control of all safety-critical functions under certain traffic or environmental conditions and
in those conditions to rely heavily on the vehicle to monitor for changes in those conditions
requiring transition back to driver control. The driver is expected to be available for occasional
control, but with sufficiently comfortable transition time. The Google car is an example of limited
self-driving automation.
•
Full Self-Driving Automation (Level 4): The vehicle is designed to perform all safety-critical driving
functions and monitor roadway conditions for an entire trip. Such a design anticipates that the
driver will provide destination or navigation input, but is not expected to be available for control at
any time during the trip. This includes both occupied and unoccupied vehicles.
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Why is Lane Selection and Target Speed a Key
Issue?
• Necessary for driver to
select lane and target speed
for limited access highways
• Currently the selection is
done more or less
subconsciously
• As lane choices become
more complex and vehicle
automation levels increase,
some level of decision
support assistance will be
required
Vehicle Navigation
(links on route
defined)
ALMA
Selection of lane
and target speed
Vehicle Control
Merge, lateral
control, longitudinal
control
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Lane selection decisions are becoming more complex
due to more intensive use of lane management
techniques in the future by highway operators
•
•
•
•
Tolling of some lanes on a freeway but not others
Tolls varying with time of day or traffic conditions
Use of shoulders varies with time of day or traffic conditions
Speed limits that vary with time of day or traffic conditions to
assist in queue control, incident management and
construction (speed harmonization)
• More frequent use of closely spaced lane control signals to
assist in construction and incident management and other
traffic control needs
• FHWA terms many of these strategies “Active Demand and
Traffic Management”
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Issues That Affect Lane Selection
• Must be allowable (proper class of vehicle, number of
passengers)
• Toll, if any, must be acceptable
• Lane must be open for some distance downstream (no
incidents, construction, lane drop)
• Lane consistent with exit point
• Speed consistent with desired motorist speed (see next slide)
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Speed Related Lane Selection Issues
• Happy with speed in current lane?
• Better match in another lane?
• Will the target lane target lane support the better
match for some distance ahead?
• Is there likely to be an appropriate gap to enter the
desired lane?
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Current Lane Selection Techniques
• Conventional Vehicles
– Motorist does not get a detailed picture of what is ahead in other
lanes.
– Leads to lane switching that does not accomplish objective
– Unnecessary lane switching causes non-productive maneuvers and
wastes fuel
– Unnecessary lane switching causes more crashes than would
otherwise be the case
• Partially and Fully Automated Vehicles
Vehicle mounted sensors and connected vehicle techniques do not
provide a sufficiently far “look ahead “ to address these issues
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Information from Traffic Management Centers
(TMCs) Can Assist
• TMCs have a wealth of information that can assist
• This information is currently boiled down and simplified for
easy dissemination, but more detailed information is often
available, particularly lane oriented information to address
lane selection issues
• Slides shown later will describe how ALMA conditions TMC
information to assist in lane and target speed selection
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What Does ALMA Do?
• Using lane based information from TMCs, ALMA conditions
this information and provides it in a form to enable the
vehicle software to make these decisions. Vehicle software
provides a recommended lane and a target speed as well as
other information based on downstream roadway conditions.
Determines whether adjacent lane conditions will support an
easy and useful lane change.
• Provides the information in a geographic reference frame that
is consistent with when and where this information is needed.
The reference frame is coordinated with highway
characteristics, locations of traffic control devices and variable
message signs. Concept illustrated in a later slide.
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ALMA Relationships
Freeway Traffic
Management
Center
Static Database (SD)
(Vehicle portion)
Operator Data Entry (ODE)
Lane signals and speed limit
controls, other information
Vehicle status
Vehicle
operator
inputs
Freeway Traffic Management
Center Interface
ALMA Data Formatter
Guidance Assist
Vehicle Module
(GAVM)
Vehicle
Navigation &
Control
Target lane and
speed,
supplementary
information
Dynamic
information
Communication to
Vehicle (broadcast)
Periodic
downloads
Static Database (SD)
Legend
ALMA Components
Other Components
ALMA Management Center
(ALMAMC)
Joint OEM/ALMA
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Information ALMA Provides to Vehicle
• Current Regulatory Conditions
– Current lane use requirements (vehicle types, vehicle restrictions,
passengers needed, use of shoulders (may vary with traffic conditions
or time)
– Current speed limits (may vary with time and/or traffic conditions)
– Current toll requirements and toll tag requirements (many new toll
installations do not accept cash)
• Lane Closure Information Displayed by Lane Control Signals
and Variable Message Signs
• Traffic Condition Information (see next slide)
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Traffic Condition Information Provided by ALMA
Lane based traffic information provided by ALMA when TMCs provide
suitable information:
• Lane speed (MPH)
• Volume (Vehicles/hr/lane)
• Average vehicle time headway (hrs/vehicle/lane)
• Average vehicle length in a lane
• Density (vehicles/mi/lane)
• Passenger car equivalents (PCE)/lane – passenger car equivalents
/hour/lane
Lane selection guidance in the vehicle uses these variables to provide
lane and speed selection guidance for issues previously described
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Roadway Segmentation for Information Delivery
ALMA provides information using the following geometric
structure:
• Barrel – A fairly long section of freeway with similar geometric
and lane use characteristics
• Zone – A fairly short section of freeway. Boundaries may be
determined by locations of control devices or by roadway
sections with similar traffic flow characteristics
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Example of ALMA Geographic Relationships - Barrel 1
Southern State Parkway Westbound - Nassau County, NY
Sheet 1
Barrel 1 Characteristics
Length – Approximately 9.5 miles
Number of entries - 17
Number of exits – 19
Number of detector stations in barrel – 23
Number of variable message signs in barrel – 3
Number of ALMA zones in Barrel 1 - 25
See sheet 1 details on next slide
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Barrel 1 Zoning (Sheet 1 of 4)
Route NY 135
28-W
E2
X1
29-1
21+98
0
E1
V
E0
21+760
28A-4
20+070
21+580
21+470
20+820
1
(29-1)
940 m
0
Wantagh Ave.
28A
20+690
X3
E4
E3
X2
20+380
20+230
20+060
2 continued
(28A)
760 m
Station Position
LEGEND
Zone
(Detector ID)
Zone Length
Detector ID
Station position
VMS ID
E3
Barrel
Start and
Termination
Note: New York State DOT
construction plan dimensions are
in meters
E0 - Entry Zone 0
X1 – Exit Zone 1
Zone demarcation
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ALMA Source Data
Most large metropolitan areas have a robust limited access highway traffic
management system. They contain motorist communication devices, variable
message signs (VMS), traffic flow detectors, CCTV cameras and other devices.
The traffic management center (TMC) hosts a robust traffic management
system that monitors and controls the field equipment. TMC functions are
described in next slide.
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Basic TMC Functions
• Monitor traffic incidents and assist emergency responders in
clearance.
• Change traffic controls and informational messages as
necessary to facilitate incident clearance and manage traffic
flow. Enter incident clearance progress into computer screens.
• Display travel conditions (often including travel time) to
motorists via on-highway devices and on web sites.
• Collect and archive data. Much more detailed information is
available at the TMC than that displayed to motorists. Some
of it is used for project and performance evaluation,
development of operational and design improvements, and
for research.
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Robert L. Gordon
36 Stauber Drive
Plainview, N.Y. 11803
(516)-938-2498
rob.gordon3@verizon.net
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