Active Safety Flashcards
Example of three Active Safety assistance systems
Night Vision, Adaptive Cruise Control, Queue Assist
Example of three Active Safety warning systems
Pedestrian warning, Lane departure warning, Collision warning.
Example of three Active Safety emergency systems
Crash avoidance, pedestrian impact mitigation, active bumpers.
Behaviour based safety: Explicit Coaching
Monitor driver with i.e a video camera. Later review videos and get coaching from “boss” etc. What could have been done differently?
Behaviour based safety: Implicit Coaching
“Nudging”.
Make driver a better driver by implicit feedback, like sounds and “feelings” like speed bumps, rumble strips.
Behaviour based safety: Safety Policies
Set up by companies to promote safe driving instead of fast deliveries etc. Zero tolerance for speeding etc.
Different types of active safety evaluation techniques.
Simulator (Low fidelity) Simulator (High Fidelity) Test Track Real World (Controlled Observations) Real World (FOT & NDS) -- Vet inte vad det betyder ännu. Counterfactual Simulations
Four different longitudinal sensors.
Vision, Radar, Lidar,GPS
Comparison between LIDAR and RADAR?
LIDAR: More moving parts, often better angular resolution, so far more expensive (scanning), More weather issues.
RADAR: Velocity by Doppler effect, not possible with LIDAR.
Why is camera-based applications usefull?
- Detection and tracking of vehicles
- Lateral positionoing
- Pedestrian detection and tracking
- Sign recognition
List some methods for evaluating active safety methods
Simulatior, Test-track, Real world (controlled observation), Real world (FOT & NDS) Counterfactual simulations
Difference between frame-transfer and rolling-shutter.
Frame transfer, captures whole image at once.
Rolling shutter, reading out line-by-line. First line will be a earlier capture of the scene than the last, leading to image distortion.
What does eye-tracking measure?
The direciton of the drivers gaze. (Direction the eyes are pointing). Used for eye-on-road-measurements.
LSB = ?
Least significant Bit
Interlace cameras are as good as progressive scan for image processing.
False
How does a GPS work?
Triangulation between three satellites. Time of flight from the three satellites is used to determine your position.
Very important that all satellites function through a common CLOCK.
One can say that there is three V’s for big data. Name these.
- Volume
- Velocity
- Variety
One can say that there is four M’s for Naturalistic Data. Name these.
- Much
- Many
- Missing
- Messy
Name three plans for Development and evaluation of
active safety systems.
Validation Plan
Test Plan
Verification Plan
What is Field Data?
Field data is data collected in real-traffic often according to an experimental protocol, which may define driver type (e.g. test engineer) and driving conditions (e.g. itinerary). It may require instrumented cars/trucks and infrastructures.
What is Field Operational Test (FOT)?
Field operational test are large collections of real-traffic
data, often performed in a naturalistic fashion, but with the aim of evaluating a system (e.g. an active safety system). As a consequence, a treatment and a baseline phase are often present in a FOT.
What can Heinrich’s Triangle be used for?
- A widely used theory in safety research
- Shows the importance of injuries
- Suggests a relation between near crashes and crashes*
Why is it a good idea to use data from near-crashes instead of “real” crashes?
crashes in naturalistic datasets are just a few
crashes in naturalistic datasets tend to be mild
anyway (so we still need to climb the Heinrich’s
triangle)
if near-crashes are indeed a good surrogate for
crashes, it may not be ethically correct to ”wait” for
crashes to be recorded.
Time accuracy of GPS?
3 ns
How does a GPS work?
Triangulation between three satelites
GPS DATA types.
Satellite Almanac Data - Satellite location (valid: days)
Satellite Ephemeris Data - Satellite ranging (hours)
Signal Timing Data - Time-tag, for positioning of user
Ionospheric Delay Data
Satellite Health Message
GPS Errors
- Ionospheric Propagation Errors - Wave propagation, 1m at night, 5-15m at daytime.
- Tropospheric Propagation Errors - 2.5m in zenith, 10-15m for low altitude satellite angles.
- Multipath Errors - bouncing.
These have been solved with DGPS:
Ephemeris Data- and On-board clock-errors. Both below 1m.
GPS protocol: NMEA messages. (National Marine Electronics Association)
- Starts with $, ends with CR/LF
- Max 80 characters
- Data items separated by commas
- ASCII
What does natural data offer?
Naturalistic environment
Long term (adaptation, learning, new strategies, etc.)
- Wider population (demographics, styles, etc.)
- Different driver status
• Different driving contexts
• Network effect (several road users interacting;
mixed traffic)
Large naturalistic driving studies provide big data (True/False?)
True