Scenarios

• Safety I
  • Source of stimulus: a non-SCUFS-compatible vehicle
  • Stimulus: vehicle enters a SCUFS highway and rear-ends a SCUFS-controlled car
  • Artifact: highway monitoring
  • Environment: normal operation
  • Response: safety maintained
  • Response measure:
    • in the first two minutes afterr the accident, SCUFS and/or driver(s) maneuver to avoid the wrecked vehicles
    • within two minutes of the accident, SCUFS regains control of vehicles near the accident site
    • within two minutes of the accident, SCUFS guides traffic around the accident in available lanes, if any
    • within two minutes of the accident, SCUFS initiates a safe traffic stop if there are no available lanes around the accident
    • within two minutes of the accident, SCUFS clears a corridor for emergency vehicles to reach the accident site
• Safety II
  • Source of stimulus: imperfect computing platforms
  • Stimulus: SCUFS software crashes in a vehicle on the freeway
  • Artifact: SCUFS vehicle monitoring
  • Environment: normal operations
  • Response: traffic safety maintained
  • Response measure:
    • driver is alerted to the failure
    • driver gains control of the vehicle
    • driver is encouraged to leave the freeway at the next exit
    • SCUFS-controlled vehicles in front of the vehicle changes lanes to clear a space three times the normal following distance
    • SCUFS-controlled vehicles behind and adjacent to the vehicle slow down to clear a space three times the normal following distance
• Availability
  • Source of stimulus: yet more imperfect computing platforms
  • Stimulus: a SCUFS server crashes
  • Artifact: system self-monitoring
  • Environment: normal operations
  • Response: traffic safety maintained
  • Response measure:
    • every vehicle in the system at the time of the crash safely completes its requested exit or stops on the highway
    • every vehicle admitted to the system between the crash and restoration of normal operation safely completes its requested exit or stops on the highway
• Capacity - normal
  • Source of stimulus: drivers
  • Stimulus: vehicles arrive at an entrance at the rate of 20 vehicles per minute
  • Artifact: entry request handler
  • Environment: normal environment
  • Response: all cars enter safely
  • Response measure: SCUFS admits all cars, with an average wait of two minutes or less for permission to enter, without accidents
• Capacity - overload
  • Source of stimulus: drivers
  • Stimulus: vehicles arrive at an entrance at the rate of 40 vehicles per minute
  • Artifact: entry request handler
  • Environment: normal operation
  • Response: safety and normal entry rate maintained
  • Response measure: SCUFS admits 20 vehicles per minute without accidents (note: there is no requirement on average wait time to enter in this scenario)
• Security
  • Source of stimulus: impatient driver
  • Stimulus: driver calls SCUFS control center, impersonates a police office, and requests an emergency corridor
  • Artifact: SCUFS call center
  • Environment: normal operation
  • Response: request rejected
  • Response measure: SCUFS rejects the request and notifies police about the attempt
• Testability
  • Source of stimulus: operating system provider
  • Stimulus: priority patch
  • Artifact: SCUFS server code
  • Environment: test
  • Response: patch certified before deployment into SCUFS operations
  • Response measure: thorough regression test executed
• Usability
  • Source of stimulus: driver who reads English or Spanish but has never been on a SCUFS-controlled highway before
  • Stimulus: driver attempts to enter a SCUFS highway
  • Artifact: in-vehicles controls
  • Environment: normal operation
  • Response: minimal assistance needed, adequate assistance provided
  • Response measure: 99% of first-time SCUFS users reach their desired exit without doubling back

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