Inter-technology Effects in Intelligent Transportation Systems

1
Inter-technology Effects in Intelligent
Transportation Systems

• By
• Seshasai Kanchi
• University of Minnesota
• Twelfth Annual Transportation Research Conference
• May 23-24, 2001

Levinson, David, Seshasai Kanchi, and David
Gillen (2002) Inter-technology Effects in
Intelligent Transportation Systems http//nexus.um
n.edu/Papers/IntertechnologyEffects.pdf
2
Intelligent Transportation Systems (ITS)
Ramp Metering (RMP)
Freeway Service Patrol (FSP)
Changeable Message Signs (CMS)
3
Key Elements and Functions of ITS
FSP
CMS
RMP

• Used in incident
• management

• Travel information
• to drivers

• Minimizes freeway
• congestion

• Help identify and
• reduce the duration
• of incidents

• Dynamic messages
• inform drivers
• about accidents

• Maximize system
• wide benefit and
• volume of vehicles

• Minimize overall
• fuel consumption

• Diminishes the risk
• of accidents

• Alternative routes
• and minimize travel
• delays

4
Objective

• Examine expected benefits of varying combinations
  of ITS applications
• Test whether technologies are sub-additive or
  super additive for one and two lane blockage

5
Input Characteristics and Assumptions

• AIMSUN2 microscopic simulator is used to model
  behavior
• of each vehicle in the network
• Test traffic network includes parallel roadways,
  ramp meters
• and changeable message signs
• Input flow characteristics are simulated using a
  pre-defined
• multi-state demand pattern over a period of 2
  hours
• Adaptive metering rates for the ramps were
  determined by
• comparing downstream bottleneck sections of
  ramps and
• system to achieve higher flow and optimal
  speeds
• The optimal metering rates are assumed to be
  unaltered even in
• the event of incidents in the downstream of the
  ramp meters
• The traffic conditions simulated only consisted
  of cars

6
Evaluation

• The efficiency of a test traffic network with
  different combinations of ITS applications is
  measured in terms of Change in Consumer Surplus
  (CS) with respect to a standard base case
• Inter-technology economy exists when the benefits
  of all technologies together exceed the sum of
  the benefits of each technology individually
• Benefits in terms of change in CS are evaluated
  to test whether technologies are sub-additive or
  super additive

7
Results

• It was observed that most of the gains were
  obtained from technology deployed first,
  successive gains were smaller
• All but one of the cases we modeled demonstrated
  sub-additive benefits
• For non-recurring congestion, the benefits from
  FSP were more than CMS or RMP
• More the severity of incidents more the benefits
  from ITS