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Active Vehicle And Traffic Safety > Exam Q:s > Flashcards

Exam Q:s Flashcards

1
Q

Describe three aproaches (data sources/analysis methods) that can be used for understand the (crash) problem in the “circle of life” for active safety development.

A
  1. Crash statics (mass data). National crash data based on police reports
  2. In-depth crash analysis: More detailed analysis of a selected number of crashes typically conducted on-site by an expert team.
  3. Naturalistic driving analysis: Analysis of naturally occuring driving behavior, near-crashes and crashes, typically by means of in-vehicle video recordes.
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2
Q

What are the different stages of Crash Prevention “The circle of life”

A

The Circle of LIfe (Crash prevention)

  1. Traffic Environment
    1. Understanding the problem - crash causation analysis
  2. Analysis/Targets
    1. Defining the solution - use cases as requirements
  3. Development
    1. Developing the solution
  4. Testing
    1. Testing the solution
  5. Production
    1. Follow up on the safety performance of the solutoin (border traffic environment)
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3
Q

Explain the roles of a target (crash scenario)

A

A target scenario describes the problem scenario (e.g. a crash) that an active safety system is intended to address

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4
Q

Explain a use case.

A

A use case defines how the active safety system is intended to address the target scenario (e.g. prevent a crash).

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5
Q
A

Mathematical models of the drive, the vehicle, the system and the environment are developed and implemented in simulation. A set of representative target scenarios (e.g., obtained from crash investigations) are implemented and run in the simulation with and without the simulated system. This yields and estimation of the porportion of target scenarios that could be prevented by the system.

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6
Q

Describe to longitudinal suppoort function.

A

Two of the following:

  • Cruise Control
  • Adaptice Cruise Control
  • Emergency Break Assist
  • Queue Assist
  • Intelligent Speed Adaption
  • Forward Collision Warning/Mitigation/Avoidance
  • Pre-Crash Brake Assistant
  • Pedestrian Detection and Avoidance
  • Safe Gap Advisory
  • Curve Speed Warning
  • Speed Alert/Speed Limiter
  • Night Vision
  • Adaptive Front Light System
  • Adaptive Bakre Lighting System
  • Platooning
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7
Q

Describe two lateral support functions.

A

Two of the following:

  • Lane Departure Warning/Lane Keeping Support
  • Lance Change Support
  • Blind Spot Monitoring
  • Roll Stability Support
  • Electronic Stability Control
  • Lane Keeping Assistance/Heading Control
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8
Q

Describe two driver awareness support functions

A

Two of the following:

  • Driver Information Management/Workload Management
  • Drowsy Driver Alert
  • Distraction Alert
  • Inattention-Sensitive Driving Support
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9
Q

Describe an example of how Active and Passive Safety are “merging” into integrated safety functions.

A
  • Pretensioning of seatbelts
  • Preparation of airbags (Triggered by Forward Collision Warning FWC, Autobrake, Electronic Stability Program ESP, Active Body Control ABC
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10
Q

Which are the three levels of Michon’s hierarchical model of driving?

A
  1. Strategic
  2. Tactical
  3. Operational
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11
Q

Explain the three levels (strategic, tactical and operational) in Michon’s hierarchical model of driving.

A
  1. Strategic level: Strategic decisions, e.g., choice of means of transport, setting of a rout goal and route-choice (where to go, when to go, how to get there)
  2. Tactical level: Decisions in local situations including speed selection, lane selection and decision to overtake
  3. Operational level: Basic vehicle-control processes, e.g., lane and distance keeping
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12
Q

Give at least 2 examples of stimulus types that are particularly efficient in capturing the driver’s attention in an unexpected situation.

A
  • Abrubt onsets
  • Movement
  • Looming
  • Stimuli with an emotional significane to the driver
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13
Q

Give 3 examples of potential unintended effects of active safety functions.

A
  • Risk compensation (e.g., reducing headway when having ABS)
  • Overreliance (e.g., take the eyes off the road and use the warning system as an alarm clock)
  • Too many false warnings leading to a “cry wolf” effect
  • Countersteering to automatic steering interventions
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14
Q

Which are the main sensory modalities that can be used to present warnings. Give an example of an existing warning type for each modality.

A
  • Visual: E.g., FCW warning using LEDs reflected in windshield
  • Auditory: E.g., Rumble strip sound for the lane departure warning
  • Tactile: E.g., Seat vibration for lane departure warning.
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15
Q

Describe the concept of graded feedback as opposed to discrete warnings.

A

Graded feedback means that the feedback from an active safety function is provided in a continuous fashion as opposted to a discrete warning that is eiter on or off.

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16
Q

Give and example of an active safety function using graded feedback.

A

Lane keeping assist providing a graded torque in the steering wheel where the strength depends on the deviation from the lane center. Artifical visual/auditory looming is another form of graded feedback.

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17
Q

Describe the problem of mode confusion in the context of automated driving. Describe a possible way to prevent it.

A

Mode confusion occurs when the human driver and the automated driving system have different “understandings” of who is in control of the vehicle. For example the driver may think that the vehicle is in highly automade mode while the system in fact has handed over the control to the driver. One way to prevent mode confusion is by always requiring confirmation from the other partner before handing over control (interlocked transitions/”handshake”)

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18
Q

Give 3 examples of components for the electric/electronic (E/E) architecture in a vehicle.

A

Components of the E/E architecture include:

  1. Wiring
  2. Connectors
  3. Sensors
  4. Actuators
  5. Lights
  6. Electronic control units
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19
Q

How has the (E/E) architecture beene evolving in the last 100 years? How can this evolution be measured?

A

There has been an exponential growth measureble in terms of wiring length, number of fuses and memory and computation capability. SW measure would also be acceptable as answers.

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20
Q

Is the evolution is beneficial for the development of active safety functions? Why?

A

As active safety systems rely on the E/E architecture, a more developed E/E architecture providing more information or computation, improve the performances of active safety systems because it enable more complicated and sophisticated functionalities.

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21
Q

What sensor/s is used and what information is the sensor providing?

A

Example : Lane Departure Warnings (LDW) make use of cameras to estimate the position of the vehicle inside the lane.

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22
Q

Describe how the threat assessment algorithm of this system looks like:

  1. What are the inputs for the threat assessment algorithm?
  2. What is the main measure used by the threat assesment algorithm to determine whether a situasion is critical and needs intervention?
  3. What is the output of the threat assessment algorithm?
A

For Lane Departure Warnings:

  1. Position in the lane (or position of lane markings)
  2. Time to line crossing
  3. The output is a digital signal triggering a warning
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23
Q

What is the vehicle-driver interface (also referred as human-machine interface) for this system?

A

LDW (Lane Departure Warnings)

From the driver to the system: activation button and in some cases sensitivity settnings. From the system to the driver: lamp on the dashboard (to convey the visual warning) and speaker (to convey acoustic warning)

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24
Q

Explain what a cooperative system is.

A

CSs are intelligent transportation systems which rely on wireless communication to enable data exchange.

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25
Q

What is V2V communication?

A

V2V stands for vehicle to vehicle and indicates the wireless exchange of information among vehicles.

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26
Q

Show an example of V2V communication for a cooperative application.

A

An ambulance may broadcast a message to make other vehicles aware of its presence.

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27
Q

Show an example of V2I.

A

V2I stands for vehicle to infrastructure (I2V stands for infrastructure to vehicle) and indicates the wireless exchange of information between vehicles and the infrastructure. A construction site able to broadcast a message to warn oncoming traffic is an example of I2V communication.

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28
Q

Which are the four main benefits of self-driving cars?

A
  1. Safety
  2. Environment
  3. Traffic flow
  4. Loewr and more efficient infrastructure investments
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29
Q

Give 3 examples of methods/tools for evaluation of active safety systems.

A
  • Field trials
  • Test track trials
  • Bench tests
  • Simulations (traffic simulations, vehicle and application simulations, driving simulators, communication simulators, micro-car simulators, etc…)
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30
Q

What is field data?

A

Field data is data collected from a real vehicle driving in traffic. It could be collected in a naturalistic way or in a test track.

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31
Q

Why may field data be “better” than data from a driving simulator for active system simulation?

A

As driving simulations rely on models which include many approximations and assumptions, field data is the only data able to prove the real system performance.

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32
Q

In a few sentences, describe the difference between precision and accuracy with respect to automotive sensors. Preferable complement your description with an illustration.

A
  • Accuracy is related to systematic errors and precision with random errors.
  • The accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quanitity’s actual (true) value. The precision of a measurement system, related to reproducibility and repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.
33
Q

Describe the concept of time-of-flight in automotive sensing.

A

Time-of-flight is the calculation of distance based on the transmission of a signal (e.g., light, radio waves and sound) and the measurement of the time it takes for that signal to come back to a receiver after having reflected off and object. Then, Distance=speed*time/2, where speed is the speed of the signal (e.g. speed of light) and time the time from the signal was transmitted until was received.

34
Q

Give three examples of different sensor types that use time-of-flight as part of its sensing.

A

RADAR, LIDAR, time-of-flight cameras, sonar.

35
Q

Choose two of the sensor types in question and provide two differences in the time of flight application between the two.

A

Different combinations.

  1. RADAR vs LIDAR: RADAR emits radio waves while LIDAR emits light. The RADAR has worse angular accuracy than LIDAR.
  2. RADAR vs Time-of-flight cameras: RADAR measures “one point” at a time while time-of-flight cameras measure the distance in pixels at the same time. RADAR uses radio waves while time-of-flight cameras use light.
  3. LIDAR vs Time-of-flight cameras: LIDAR measures “one point” at the time while time-of-flight cameras measures the distance in all pixels at the same time. The time-of-flight camera has range limited by the transmitted signal’s pulse lenght while the LIDAR range is primarily limited by the reflectivity of objects the transmitted signal encounters.
36
Q

Which of the following Active Safety Systems support lateral control?

  • Frontal Collision Warning (FWC)
  • Blind Spot Monitoring (BLISS)
  • Adaptive Cruise Control (ACC)
  • Lande Departure Warning (LDW)
  • Driver Alert System (DAS)
A
  1. Blind Spot Monitoring
  2. Lane Departure Warning
  3. Driver Alert System
37
Q

Explain the different levels of Michon’s hierarchical model on driving.

A
  1. Strategic level
  2. Maneuvering level/Tactical level
  3. Control level/Operational level
38
Q

Explain Michon’s Strategic level and give two example of related active safety systems.

A

Strategic Level

  • Strategic decisions are made e.g. choice of means of transport, setting of a route goal and route choidce (e.g. where to go, when to go, how to go there)
  • Driver information systems:
    • Aim to support the driver on the strategic level of the driving task
    • Although the driver remains in full control, his/her situation awareness can be increased by additional information
    • Conscious decision, general plan
  • Examples of Active safety systems:
    • Advanced route navigation
    • Traffic sign recognition
    • Night vision
    • Adaptive light control
39
Q

Explain Michon’s maneuvering level and give 2 examples of active safety systems.

A

Maneuvering/Tactical Level

  • Reactions to local situations including reactions to the behavior of other traffic participants (e.g. speed selection, decision passing other road users, choices of lanes)
  • Driver warning systems:
    • Support the driver on the maneuvering level of the driving task and actively warn the driver of a potential danger
    • Driver can then take appropriate actions in order to mitigate or completely avoide the dangerous event.
  • Examples of Active Safety System:
    • Parking assistant
    • Lane departure warning assistant
    • Blind spot warning
    • Intersection collision warning
    • Driver drowsiness warning
    • Forward collision warning systems
    • (ACC)
40
Q

Explain Michon’s Control Level and give 2 examples of active safety systems.

A

Control/Operational level

  • Basic vehicle-control processes, e.g. lateral-position control, desired speed, distance, keeping the car in the lane (more automatic processes)
  • Intervening systems:
    • Provide active support to the driver on the control level of the driving task.
    • Systems are able to take over longitudinal or lateral control of the vehicle and perform parts of the driving task automatically
  • Examples:
    • Lane keeping
    • Intelligent Speed Adaptation (ISA)
    • Adaptive Cruise Control (ACC)
41
Q

What are the 3x3 dimensions of Michon’s hierarchical model on driving?

A
42
Q

Explain the concept of “Risk Homeostatis” in the field of Active Safety systems. Use on example to explain the concept.

A

Risk homeostasis

  1. Driver’s motivation to seek som level of optimal or accepted risk (i.e. target risk) which guide his or her behavior.
  2. The target risk depends on driver’s knowledge of accident rate.
  3. However, active Safety systems affect the sbujective risk of the driver!
  4. Counter measures that aim to enhance traffic safety inevitably do not lead into an incread on but may also have a converse effect.
  5. Drivers tend to adapt to the traffic situation by taking more risks than before the measures where introduced
  6. Overall, if there is a discrepancy between target risk and risk experienced, this will lead to behavioural changes to reduce this discrepancy.
  7. While reducing the complexity of the traffic situations with the introduction of new safety devices will not necessarrily reduce traffic accidents!
  8. Cost-benefit evaluation

EXAMPLE: ABS function - Driver will adjust his or her behavior to the level of optimal risk, e.g., delay braking, increase speed or shorter head ways etc.

43
Q

Discuss the main focus of risk theories for understanding the driving task compared to the main focus on hierarchical models.

A

Risk Theories: Level of risk that drivers tolerate

  • Hierarchical models: Driving is mainly seen as response to the traffic situation, in different levels -> different level of automatic of action plans.
  • However, driving is no only the response to the situation.
  • Risk theories are taking the driver and his/her risk level into account.
  • Main focus of driver’s experience of risk, or the avoidance of risk, as the main motivator behind driving.
  • The motivation of a driver influences his perception, his expectations, his/her subjective risk and desired actions.
44
Q

Describe Haddon’s matrix.

A
45
Q

Explain the term “schemata” in the context of the driving task and explain why schemata are important for the driving task.

A
  • Schemata:
  • Mental model -> Organized pattern of thought or behavior (a framework)
  • Cognitive structures that:
    • Prepare the perceiver to accept certain kinds of information rather than others
    • Pick up the information that the environment offers
    • Control the activity of looking
  • Most situations do not require effortful thought when using schema, since automatic thought is all that is required!
  • Influence attention and the absorption of new knowledge: People are more likely to notice things that fit into their schema.
  • = Expectations
  • Anticipate certain kind of information
  • Direct exploration of the environment for that information, and
  • Prepare the observer to perceive it.
  • Schemata expect events to change its shape and tell us what to do about it.
    • Velocity control
    • Steering control
    • Warnings
    • …

In psychology and cognitive science, a schema (plural schemata or schemas) describes a pattern of thought or behavior that organizes categories of information and the relationships among them.[1] It can also be described as a mental structure of preconceived ideas, a framework representing some aspect of the world, or a system of organizing and perceiving new information.

46
Q

Which type of accident can an ACC system decrease?

A

Rea

47
Q

Explain the functional operation of an ACC system. Make a drawing to clarify the system.

A

Description ACC:

  • Also “Autonomous Intelligent Cruise Control” or “Intelligent Cruise Control”
  • Adjusts the vehicle speed to maintain a safe distance from vehicles ahead
  • By setting the desired speed, the vehicle follows the car in front with automatic accelerationg and braking -> if the curren preselected speed or headway would lead to a collision
  • Driver-selected “time-gap” between the front bumper of the sbjuect’s vehicle and the rear end of the lead vehicle.
  • In the absence of a vehicle ahead, the ACC system operates like a conventional cruise control by maintaning the speed set by the driver.
  • Improves Cruise Control in terms of automatic brakin or dynamic set-speed type controls.
48
Q

Which HMI is mainly used for ACC?

A

HMI

  • Visual HMI
  • The driver cant speed and time gap
  • ACC provides the driver with a sound when the ACC automatically disengage below a certain speed
  • ACC needs to be reactivated at any stop by the driver (touching the brake)
49
Q

What sensors are used in ACC?

A

Sensors ACC

  • Only on-board sensor information (radar, lidar or machine vision)
  • No use of satellite or roadside infrastructures nor of any cooperative support from other vehicles
  • Measuring distance and speed of the SV
  • Braking capacity is limited to around -3m/s^2 -> the reason why it is not an FCA(??)
50
Q

What are the benefits with ACC?

A

Benefits

  • Reduce driver workload in dense traffic
  • 25% decrease of rear-encollisions
  • ACC can reduce brakin reaction times from 0.7 - 1.5 s to 0.1 s
  • The intervening function of ACC may additionally serve to alert inattentive drivers
  • Can have positive or negative effects on traffic flow (longer and shorter time gaps) high capacity
  • More stable traffic flow by means of smoother acceleration and deceleration profiles
  • System enables driving at shorter headways and higher speeds which increases roadway capacity
  • Less maximum and mean speed and headway variance -> safer conditions which reduces the likelihood of crashes.
  • ACC may reduce the incidence of all types of crashes by ca 6%
51
Q

What are the disadvantages of ACC?

A

Disbenefit

  • Behavioral adaptation to the system may actually counteract its safety benefits by driving more riskily
  • Higher speed, smaller minimum time headway and larger brake force
  • Current range of ACC sensors of around 200m, which is not sufficient for timely recognition of an oncoming traffic jam or other potential danger further ahead
  • Depending on the vehicle load, road grade, and vehicle performance parameters, the level of decelartion control typically used by the system is limited to a range between 0.1 and 0.3 g (g= a unit of forve equal to the force exerted by the gravity) -> not a brake assistante. Estimate best acceleration and deceleration (load, slope, etc)
  • May glance “off-road” more frequently and longer
  • Reduction in driver workload was shown to result in driver inattention -> longer hazard detection reaction times.
  • ACC may serve to increase driver comfort but not necessarily safety!
  • Reliability, user ability to recognize a system malfunction, acceptability
  • Inconsistencies in the effectiveness of ACC.
  • ACC can be effective at reducing speed variability, but may be associated with increase average speed and reduced headway, although these findings are not consistent
  • Harsh deceleration, should a false alarm occur.
52
Q

Give 4 examples of scenario types which are typically addressed with Adaptive Front Light Systems.

A

Adaptive Front Light Systems

  1. Car turns right or left, the lights direct to the right or to the left.
  2. Car goes through a bump, the head lights always keep down.
  3. Car detects an oncoming car or pedestrians in front of the car, the system automatically adjusts the lightning range based in the distance of the oncoming vehicle or pedestrians
  4. Car turns into a curve with low speed, the concerning lights are activated to illuminate the side of the car.
  5. Car goes on high speed on motorway, with increasing of car’s speed, the power of the lamp is raised to improve the illumination range.
  6. Adverse weather conditions, e.g. in fog or rain, the head lamp can be directed to avoid the self-glare.
53
Q

Which crash types LDW systems addressing? Give 3 crash types.

A

Crash types and crash relevance Lane Departure Warning

  • Vehicle leaving the lane and striking oncoming traffic in the opposite carriageway (head-on)
  • A vehicle is leaving the lane and striking oncoming traffic travelling in the same direction in an adjacent carriageway (sideswipe crashes)
  • A vehicle is leaving the lane and the roadway and striking a stationary object and/or rolling over.

Crash Relevance:

  • Head-on, off-path on straight; off-path on curve; sideswipe crashes

Crashes where fatigure or inattention/distraction are factors.

54
Q

What are Visual Warnings good for?

A

Visual warnings are good for:

  1. Unobtrusive warnings/non-urgent information/self-paced presentation
  2. Complex, long and many messages
  3. Discrete and continuous informatoin
  4. Temporally and spatially free access
55
Q

What are the disadvantages with Visual warnings?

A

Visual warnings are not god foor:

  1. Conveying time-critical information/forced-paced presentations
  2. Poor illumination conditions
  3. Configuration with unrestricted driver viewing angle and position
56
Q

Give two advantages and two disadvantages of using visual modalities to inform/warn the driver in context of the LDW systems.

A

Advantages:

  • Good for complex information
  • Directional cueing
  • Could give more informaiton than auditory signal
  • Good to provide continuously available information
  • Good for non-urgent information
  • Good for spatial information (Visual Images)
  • Notable in nosy environment

Disadvantages:

  • Eye fixation required
  • Could be language dependent
  • Not omni-directional, can therefore not be relied upon to capture the driver’s attention
  • Visual overload if too much
57
Q

What are Auditory warnings good for?

A

Auditory warnings are good for:

  1. Getting the attention of a driver who is distracted or looking away from a visual warning
  2. Time-critical information
  3. Low complexity, high priority messages
  4. Few and short messages
  5. Discrete, sequential or spatially-localized information
58
Q

Whare Auditory warnings not good for?

A

Auditory warnings are not good for:

  • Frequent warning messages because they are obtrusive and can be annoying
  • Continuous information
  • High complexity/informational messages
  • High-noise environments that can mask auditory warning signals (techniques for mitigating auditory masking may be necessary)
59
Q

Give two advantages and two disadvantages of using Auditory modalities to inform/warn the driver in context of the LDW systems.

A

Advantages of Auditory modalities for LDW systems:

  • Omni-directional, can command attention regardless of where the driver is looking
  • Reduce visual workload
  • Directional cueing
  • Could describe urgency levels better than tactile warnings
  • Reduces perception-reaction times
  • Improves driver awareness of warning/information
  • Good for time-critical information that requires attention
  • Good for few and short messages

Disadvantages

  • Could be more annoying and may be turned off
  • Difficult to accommodate hearing impaired drives
  • Signal detection problem under high ambient noise conditions
  • Could cause unwanted “startle” response
  • Not discrete and personal
  • Not good for frequent messages
  • Not good for continuous information
  • Auditory overlad if too much.
60
Q

Haptic warnings are good for?

A

Haptic warnings are good for:

  1. Obtrusive attention getting
  2. Providing warning information if other modalities are overloaded
  3. Providing simple information if it is given in the appropriate context and proved direct intervention in the manual control processes (e.g. steering torque naturally advises a driver against further steering against the torque)
61
Q

What are Haptic warnings not good for?

A

Haptic warnings are not good for:

  1. Providing complex and potentially ambigious information
  2. Systems that provide limited exposure to warnings because drivers are likely to require some learning to distinguish them fron natural driving sensations (e.g. rumble strips)
62
Q

Give two advantages and two disadvantages of using Haptic modalities to inform/warn the driver in context of the LDW systems.

A

Advantages of Haptic Modalities in Lane Departure Warning systems

  • Omnidirectional
  • Good for simple urgent info thar requires attention
  • Reduce visual and auditory workload
  • Consistent with driver’s mental model
  • Notable in nosy environment, unaffected by background noise
  • Appropriate to present hight priority alerts and warnings
  • Discrete and personal
  • Small number of competing demands for this source

Disadvantages

  • Potential misperception as mechanical failure
  • Unable to convey detailed information
  • Require some learning to distinguish from natural driving sensations
  • Only effective if the driver is in contact with tactile source
  • Can be annoying
  • For now there is insufficient data to claim that tacticle ICWs are equally effective as auditory ICWs.
63
Q

Explain the functional operation of a BSM system.

A

Description Blind Spot Monitoring BSM system

  • Description
    • Supports the driver byb signaling the presence of other vehicles in the ego-vehicle blind spots
    • To facilitate safe lane exchanges on motorways
    • System looks to the side and behind, if there is a vehicle in the blind spot, a lamp lights up on the exterior rear-view mirror.
    • LCA incorporates basic blind spot monitoring, which is fundamentally a short-range sensing mode, with longer range sensing to detect vehicles in adjacent lanes which may be rapidaly approaching and could also pose a hazard in a lange change maneuver.
    • Lance Change Assist is BSM + longer range sensing.
    • Other advanced systems may also monitor the road ahead, detecting oncoming vehicles that may present head-on crash hazards while overtaking. These LCA systems are based on laser scanners at a range of up to 200 m.
64
Q

Situations where BSM is useful.

A

Blind Spot Monitoring

  1. Lange change
  2. Turning at junctions
  3. Merging
  4. Drifting
65
Q

Benefits BSM.

A

Benefits of Blind Spot Monitoring:

  1. Lane change assistance has the potential to affect 20% of off-path fatalities in Sweden.
  2. Crashes could bed reduced by 37% with lane changing and merging systems.
  3. Lane change collision avoidance system has been estimated to be relevant to 96% of all lane change crashes annually in USA and approximately 40 % of these are expected to be prevented.
  4. Benefits: 8% less accidents when changing lanes on motorways.
  5. Important for heavy vehicles and bus crashes.
  6. Combined warning and/or avoidance systems: Collision avoidance, lane change and road departure systems could prevent over 1.8 million crashes annually in the US.
  7. 60% reduction in the occurrence of side-swipe crashes and a 10% decreases in side-swipe crash injury severity with combined lateral collision warning and lane departure warning systems.
66
Q

Disbenefits of BSM.

A

Disadvantages of Blind Spot Monitoring

  1. Camera limitation
  2. Dirt, snow, mud and other miscellaneous debris can build up on a blind spot object detection sensor, preventing proper operation.
  3. Detecting ONLY non-stationary targets.
67
Q

Driver Alert systems monitor the performance of the driver and are aimed at providing the driver a feedback in case his/her driving performance reaches a low level. Give 4 examples of how fatigue effects driving performance!

A

Fatigue effects on driving performance:

  1. Incrieased drifting within lane
  2. Crossing the road center line or side line
  3. Poor speed control
  4. Late corrections to lane positioning
  5. Slower reaction time to stop lights and poor avoidance of hazards
  6. Vehicle lateral position and speed, such as acceleration, steering wheel movement and lane position.
68
Q

Driving simulators are used to investigate the effectiveness of novel or existing active safety systems in different driving situations and drivers’ behavior with and without these systems. Dicuss pros and cons of using a driving simulator for safety research.

A

Pros

  • Good way to test HMIs and safety critical situations or fatigue
  • Cheap compared to field testing
  • Repeated measure from the same situations

Cons:

  • Not really able to catch the actual driver behavior
  • Simulator sickness
  • Many traffic/weather condition are not possible to test in simulators
69
Q

What is a bench test?

A

Bench test:

  • The new system (rapid prototyping;alfa)is tested in a controlled environment with the help of specific measurement equipment.
    1. stage of research testing
  • Pros: cost-efficient and fast to assemble way for preliminary tests
  • Cons: only specific conditions and specific parts can be tested, the system is still a very early prototype.
70
Q

What are the excitatory motives and inhibitatory motives?

A

Driver motives are factors influencing driver behaviours. Excitatory motives (e.g. goal achievement, social pressure, secondary task completion) will encourage drivers to accept shorter time headways and higher speeds. Inhibitatory motives (e.g. risk aversion, effort) will push drivers towards larger time headways and smaller speeds.

71
Q

What is expectancy about automation?

A

Expectancy of automation can be thought as the statistical prediction of automation behaviour based on previous experience training (e.g. conditional probability=. Based on expectancy, the driver will build expectations about how automation will act in the future. For example: IF Adaptive Cruise Control always worked according to the driver’s mental model of the system,, the driver will expect ACC to work in the same way in similar future situations.

72
Q

Explain the functional operation of near-infrared sensors.

A

NIR

Sensors: Active Systems

  • Near-Infrared energy!
  • Infrared light which illuminates the road in front of the car and cameras to capture the surrounding (250 m)
  • Employ illumination or scanning techniques to visualize the roadway
  • Higher performance in rain and snow
  • Provides a more natural-looking image to the driver than traditional thermal (far-IR) night vision
  • Allow the driver to see “cold” objects such as trees
  • Is not visible to humans so oncoming drivers are not affected
  • Detection range is less than traditional thermal (far-IR) night vision.
73
Q

Pros and Cons NIR

A

Near-Infrared sensors

Pros:

  • Higher resolution image, superior picture of inanimate objects
  • Provides a more natural-looking image to the driver than traditional thermal (far-IR) night vision.
  • Allows the driver to see “cold” objects such as trees
  • Works better in warmer conditions.
  • Smaller sensor can be mounted to rearview mirror
  • Is not visible to humans so oncoming drivers are not affected
  • A fast modulation and synchronization with cameras for fast video recordings is possible.
  • Intelligent image analysis programs operate better with active IR systems

Cons:

  • Shorter range of 150-200 meters or 500-600 feet -> Detection range is less than traditional thermal (far-IR) night vision.
  • Lower contrast for animals
  • Does not work well in fog.
74
Q

Explain the functional operation of FIR

A

Far-Infrared sensor

Sensors: Passive Systems - FIR

  • Far-Infrared!
  • Thermal imaging cameras which capture the heat trace of the surroundings (thermographic camera)
  • Detect the naturally radiated energy from objects in the environment
  • Difference in temperature
  • Use the image processing technology and pattern recognition to detect the pedestrian during the night driving
  • Automatic visual recognition can be used to warn the drive
75
Q

Pros and Cons FIR

A

Far Infrared sensors Passive System

Pros:

  • Greater range of about 300 meters
  • Higher contrast for living objects
  • Detection of hot objects to cold environments very suitable

Cons:

  • Poor resolution (typically 320-240 pixels)
  • Grainy, lower resolution image
  • Works poorly in warmer weather conditions (e.g. desert)
  • Larger sensor, less effective in rain and fog
  • Not suitable for the identification of text or numbers
  • Cannot be observed by other IR-sensitive systems.
76
Q

What are the disadvantages and challenges of night vision?

A

Challenges Night Vision:

  • Better vision but still judgment to the driver to react
  • Extra workload for the driver while using only image showing displays decreases their ability to focus on the driving.
  • Tendency for users to driver at higher speeds.
  • False alarms, e.g. in very crowded areas.
  • Near-Infrared systems detect reflected light
  • Cost factor
77
Q

What are the challenges in detection pedestrians? Discuss from a sensors point of view and from a safety point of view.

A

Challenges Pedestrian Detection Systems

  1. Detection of pedestrians mobility
  2. Detection of moving pedestrians in a cluttered visual field is a challenge for any such system, as they may vary in height and width (physical size, orientation to the vehicle) as well as speed.
  3. Sensors must be powerful enough to detect the “object” with enough time for evasive action to be taken, with a minimal risk of false alarm.
  4. Pedestrian detection from a moving vehicle is very more complex, as all aspects of the image are in motion.
  5. Compex urban scenario, e.g. occlusion betweed pedestrians but also due to objects.
  6. Tracking when pedestrians pass behind obstacles, such as telephone poles (pedestration may shortly disappear for the IR cameras) -> disappearance and reapperance of pedestrians.
  7. Must be able to recognize pedestrians when they are partially or temporarility completely obscured by objects in the road environment
  8. Sensors must be able to differentiate the characteristic shape and movement patterns of pedestrians of all sizes (vehicle itself is moving)
  9. Pedestrians with heavy clothing (which may distort their shape and IR signature) must be detected
  10. Early detection also requires robust acquisition of people parts such as heads and torsos when the otal body outline is obscured.
  11. Mus be able to do this while the vehicle itself is moving.
78
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79
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Active Vehicle And Traffic Safety (7 decks)

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