Surveillance

Document Sample
Surveillance Powered By Docstoc
					Surveillance
              Surveillance
• Is necessary to manage traffic

• Without surveillance, there is no knowledge
  of what is occurring
                Surveillance
• When choosing surveillance system /
  technology
  –   Type of data collected
  –   Cost of data collection
  –   Accuracy of data collected
  –   Reliability of equipment
  –   Frequency of communications
  –   Flexibility
                Type of Data
•   Volume
•   Vehicle presence
•   Lane occupancy
•   Vehicle classification
•   Vehicle speed / travel time
•   Weight
•   ID
•   Other (location? status? revenue?)
             Cost of System
•   Purchase
•   Installation
•   Operation
•   Maintenance
                     Cost
• Purchase price
  –   Sensor
  –   Electronics
  –   Communications
  –   Software
  –   License? (How many can you use?)
                         Cost
• Installation location effects cost
    –   In ground
    –   Below ground
    –   Pole mounted
    –   Bridge mounted
•   Need for traffic control?
•   Communications
•   Power
•   Cabinets
                      Cost
• Operations
  – Power
  – Communications
     • Bandwidth required
     • Wireless / wireline
     • Frequency of communications
  – Staff oversight
                       Cost
• Maintenance
  – Mean time before failure (life cycle costs)
  – Routine maintenance requirements
  – External effects
     • Bad weather
     • Deteriorated pavement conditions
  – Replacement parts (sole source?)
  – Ease of sensor replacement
                      Accuracy
• How important is it?
  – Can you accept small errors?
     •   Volume +5%
     •   Speed + 3 mph
     •   Error in reading Toll tags?
     •   Classification of truck
• It depends
                   Reliability
• What happens if a data point is missing?
  –   Once
  –   Frequently
  –   Consistently but intermittently
  –   Completely
• Fail safe design
• Graceful failure design
                 Reliability
• To get better reliability

   – Purchase better equipment (price / warranty)
   – Build redundantly


• Must trade off against cost
           Communications
• How often does data get transmitted from

  – Sensor
  – Location
             Communications
• Frequency of communications
  –   Each activation?
  –   Each second
  –   20 seconds
  –   5 minutes
  –   15 minutes
  –   Hourly
  –   Daily
             Communications
• Size of data packet
  – Summary statistic
  – Raw data


• For example
  –   Digital image of picture
  –   Analog image of picture
  –   Count of cars made from picture
  –   Count of cars made from 15 minutes of pictures
             Communications
• Must select communications strategy based
  on
  – Control system data need
  – Cost of bandwidth
     • Installation
     • Operation
  – Redundancy / reliability
      Surveillance Technologies
• Loops
• Cameras
• Other technologies
  –   Radar
  –   Acoustic
  –   Infrared
  –   Other
Inductance Loop
                           Loops
• Advantages
  –   Inexpensive
  –   Easy to install
  –   Well known attributes / mechanics
  –   Provide
       •   Volume
       •   Lane occupancy
       •   Speed (sometimes)
       •   Vehicle classification
                        Loops
• Disadvantages
  –   Single location (non-movable)
  –   Subject to pavement failure / degradation
  –   Not good if channelization is likely to change
  –   Difficult to collect vehicle classification data
       • Dual loops
       • Inductance signature recognition
Pan/Tilt/Zoom Camera
                 Cameras
• Two basic technologies

  – Video (often analog)

  – Digital image processing
                    Cameras
• Conventional video
  – Needs a person watching
     • Great for short time period
     • Poor for longer time periods
  – Good for incident verification
  – Good for public information
  – Not good for routine data collection
                 Cameras
• Digital Image Processing
  – Reasonably new technology (+15 years at a
    reasonable price)
  – Several different technologies
  – Each with different costs / capabilities
                    Cameras
• Autoscope - style
  –   A US vendor – early adopter
  –   Uses low cost, fixed cameras
  –   Acts like a digital loop
  –   Has limitations in bad weather / lighting
                    Cameras
• Other digital image processing
  – Movable cameras
     • Harder to calibrate
     • More expensive cameras
     • Multi-use cameras
  – Vehicle tracking systems
     • Travel times
     • License plate readers
         Other Technologies
• http://www.nmsu.edu/~traffic/

• Summary of Vehicle Detection and
  Surveillance Technologies Used in
  Intelligent Transportation Systems -
  Detector Handbook (under What’s New)
          Other Technologies
• Radar
  – Side fired / Over-head mounted
  – Data similar to loops
  – A non-intrusive sensor (easier to access)
• Acoustic
  – Also a non-intrusive sensor
          Other Technologies
• Infrared
  – Both with reflector and without reflector
  – Non-intrusive
  – Not effected by weather
• Other
  – RF for electronic tag reading
  – Surface acoustic wave (SAW) for tag reading
  – Optical scanners (bar codes)
Piezo-Ceramic Cable WIM
    Control System Integration

Integration - Making two independent systems
                 work together
           Why Integration?
• It increases the data/information available
  for operational controls
• Shared infrastructure can reduce costs
• Avoid duplication of infrastructure
• Allows knowledge of conditions outside of
  your control boundaries
           What duplication?
• Examples:
  – Toll tags – one tag for multiple toll roads

  – Surveillance equipment

  – Communications – Two different in-vehicle
    components can share one off-vehicle
    communication system
   Integration
Component integration

        Versus

 System integration

  (Similar but different)
    Control System Integration
• Two important aspects of integration

  – Technical integration

  – Administrative integration
        Technical Integration
• Allowing independent components to work
  together:
  – E.g. Stereo system components


• Hardware connections
• Software compatibility
        Technical Integration
• Biggest issue is standardization
  – New technology
  – Existing technology


• National Architecture
  – Physical layer
  – Logical Layer
        Technical Integration
• Physical layer

  – Standardized hardware connections
     • Plugs
     • Cables
     • Communication inputs
        Technical Integration
• Software

  – Data transfer protocols
  – Transfer speed
  – Data transmitted
     • Content
     • Format
     • Units
        Technical Integration
• Component versus system integration

  – Difference in degree of “integration”
    Administrative Integration
                    Issues

• Do I really want to share with “them?”

• Who pays for what?

• Who is responsible for and/or controls
  what?
     Administrative Integration
• What type of integration?
  – Shared control
  – Shared data
  – Shared infrastructure
     • Communications
     • Shared components (tags)


• This drives willingness to participate
   Administrative Integration -
             Issues
• Do I want to?
  – What do I get?
  – How much does it cost?
  – What control do I have?
     • Is my system dependent on someone else?
     • Is my system effected by theirs?
  – Privacy
     • System operator
     • User
  Administrative Integration

Decision is based on benefits versus cost
      Administrative Integration
• Benefits
  –   Good will
  –   Cost reduction
  –   New data
  –   New capabilities
  –   Happier user
    Administrative Integration
• Costs?
  – Extra infrastructure
  – Added functionality may lead to less than
    optimum component features for your original
    purpose
  – Purchasing limitations
  – Added complexity to the original system
  – Loss of control
  – Customer reaction
      Administrative Integration
• Control
  – The more critical to your goal, the less likely
    you are to let others control the system

  –   Reliability
  –   Response time to problems
  –   Control decisions
  –   Cost versus responsibility
     Administrative Integration
• Privacy
  – User information
  – Company information
  – Freedom of Information act


• Value of data versus cost of data
• Does access to data limit participation?
    Administrative Integration
Agencies agree to integration when

  – They see more benefit than cost

  – When the cost is within their available budget

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:33
posted:7/30/2012
language:English
pages:49