Naturalistic Driving Studies Flashcards
What is the motivation behind Heinrich’s Triangle?
Crash injuries are very infrequent compared to non-injury crashes and near-misses
What is the hazard analysis technique developed by Heinrich, Petersen, & Roos (1980) based upon?
The underlying premise that for every injury accident, there are similar accidents for which no injury occurs.
What does Heinrich’s theory suggest?
that the same contributing factors occur for both injury and non-injury traffic events
If the same contributing factors occur for both injury/non-injury accidents, like Heinrich’s theory suggests, how can we reduce the number of crash injuries and fatalities?
By reducing the number of non-injury traffic events
How many minor crashes and near-misses are there for every serious crash according to Heinrich’s Triangle?
30 minor crashes
What is a traffic conflict?
An event involving two or more road users, in which the action of one user causes the other user to make an evasive maneuver to avoid a collision.
Describe the Traffic Conflict Technique.
What company used Heinrich’s Triangle to develop the Traffic Conflict technique of instrumenting intersections?
GM
What did Wierwille (2002) employ the Traffic Conflict Technique to evaluate?
Driver errors
At what kinds of intersections did Wierwille (2002) employ the Traffic Conflict Technique to investigate driver error?
rural, suburban, and urban intersections that had a high percentage of collisions
How has the Traffic Conflict Technique been developed for instrumented vehicles?
By videotaping the behavior of the driver in relation to the surrounding traffic
What is considered the birth of naturalistic driving studies?
Application of the Traffic Conflict Technique to videotape the behavior of drivers in relation to surrounding traffic via vehicle instrumentation.
What is a field operation test (FOT)?
Large-scale naturalistic driving studies for assessing the safety aspects of a particular in-vehicle safety system
Aside from field operation tests (FOTs), what can naturalistic driving studies be used for?
To better understand driver behaviors that result in crashes
What is of utmost importance in field operational tests and naturalistic driving studies?
driver behavior in real-world conditions
What is the advantage of evaluating driver behavior in real-world conditions (field operational tests and naturalistic driving studies)?
High external validity
What three real-world factors of field operational tests and naturalistic driving studies result in high external validity?
- Normal routes
- Normal daily pressures
- Normal traffic conditions
What is a limitation of naturalistic driving studies and field operational tests?
No experimental control
How do naturalistic driving studies and field operational tests attempt to overcome the lack of experimental control?
By:
- recruiting large numbers of participants
- collecting data over long periods of time
- collecting data over a variety of traffic patterns and environmental conditions
What is the primary strength of naturalistic driving studies?
Coupling of:
- high quality/high-resolution performance data
- Video data
What does driving performance data provide?
Precise description of driving performance in normal driving environments
What strategies are used to maintain the power of naturalistic driving data?
- Minimize interaction with participants
- Minimize instrumentation
- Don’t require participants to do anything beyond driving normally
What are the six steps in the life cycle of naturalistic driving studies?
- Study design
- Data collection
- Data preparation
- Data storage
- Data coding
- Data analysis
What are important considerations in study design and data collection in naturalistic driving studies?
- What research questions do you have?
- What data must be collected to answer these research questions?
- Research questions should guide what data elements will be collected in naturalistic driving study
- Appropriate research questions will also lead to participant selection
- Protection of participants personal identifying information
What are important considerations in data preparation and storage in naturalistic driving studies?
- How to ensure high-quality data
- How will data be stored to better prepare for data coding and analysis?
- Storage on vehicle
- Long-term storage
- Continuous vs triggered data collection
What are important considerations in data coding in naturalistic driving studies?
What behaviors should be coded to answer research questions?
How to ensure high-quality data coding
What are important considerations in data analysis in naturalistic driving studies?
What data and what statistical analyses will best answer research questions?
How do research questions influence data collection in naturalistic driving studies?
They should guide the selection of data elements to be collected
What are three pros of naturalistic driving studies?
- versatility
- flexibility
- easy to collect large volumes of data elements
What are two important considerations in naturalistic driving studies?
project creep and cost overruns
What is project creep?
changes, continuous or uncontrolled growth in a project’s scope, at any point after the project begins
How do research questions impact recruitment?
Appropriate research questions guide participant selection
What are three examples of participant attributes that appropriate research questions consider?
- age
- gender
- geographic distribution
How is participant PII protected in naturalistic driving studies?
Certificate of Confidentiality from the National Institutes of Health
What is the next step after data elements are determined for the data acquisition system (DAS)?
The appropriate data storage device must be selected
What are the pros of triggered data collection?
- less storage-intensive
- provides high resolution for specific events
What is a limitation of triggered data collection?
Data is limited to the pre-specified events once data collection is complete
What are some important considerations with continuous data collection in naturalistic driving studies?
- It is not trivial
- Must weigh storage vs resolution
- video quality
What is an important question to consider when weighing storage and resolution?
What resolution can I get away with to still answer research questions that will not overrun my budget with storage costs?
What does data storage on a vehicle require?
- security (encryption)
- maintenance
- removability
What does long-term data storage require?
For both driving performance and video data:
- processing speed
- access
- security
Describe the process of data coding?
lengthy and iterative
What are the 7 steps of data coding?
- Identification of events
- Development of coding protocols
- Training of coders on coding protocols
- Reviewing data
- Coding data
- Inter-rater and intra-rater reliability testing
- Final internal quality check
What is the purpose of inter-rater and intra-rater reliability testing?
to ensure quality coded data
What are four considerations in data coding protocols?
- Driver behavior in relation to:
- safety-critical events
- specific traffic scenarios (e.g.intersection behavior)
- “Normal” driver behavior (control, baseline)
- Manual eyeglance coding
What are typical variables coded in safety-critical events?
- Subject Number
- Event Start
- Subject Reaction Start
- Impact or Proximity Time
- Event End
- Pre-incident Maneuver
- Maneuver Judgment
- Precipitating Event
- Vehicle Configurations (GES codes)
- Event Nature
- Incident Type
- Event Severity
- Evasive Maneuvers and Vehicle Control
- Airbag Deployment
- Vehicle Rollover
- Driver Behaviors
- Driver Impairments
- Passenger Presence
- Secondary Task Types, Durations, Influence
- Hands-on the Wheel
- Driver Seatbelt Use
- Vehicle Contributing Factors
What are typical SCE and control segment coded variables?
- Infrastructure
- Visual Obstructions
- Lighting
- Weather
- Surface Condition
- Traffic Flow
- Contiguous Travel Lanes (number)
- Through Travel Lanes (number)
- Lane Occupied
- Traffic Density
- Traffic Control
- Relation to Junction
- Intersection Influence
- Alignment
- Grade
- Locality
- Construction Zone
- Other Motorists, Non-motorists, Objects, and Animals:
- Quantity
- Location
- Type
- Maneuvers
- Final Narrative
What are the four steps involved in coder training and quality control?
- Protocol development
- Data coder training
- Data coding
- Post-coding
Describe protocol development.
An iterative process with researchers and data coding managers
What are the two steps of coder training?
- Train to a priori set level of accuracy (e.g. 95% accurate to expert coder)
- Spot check 100% of work until this level has been achieved
What are the components of data coding?
- periodic spot checks
- meetings to discuss conflicting coders
- reliability testing
- inter-rater
- intra-rater
What are the post-coding steps?
- spot checking
- data verification
- final data review
What are four considerations in naturalistic driving data analysis?
- assessing crash risk
- assessing prevalence
- contributing factors of safety-critical events
- advanced product testing
What are three ways of estimating crash risk?
- odds ratio
- relative risk
- logistic regression
How is odds ratio calculated?
- Simplified explanation
- Odds = P(Event will occur) / P(Event will not occur)
- Odds = P(crash with inattention occurs)/P(crash occurs without inattention
- Actual calculation
- Odd Ratio = AD/BC
- Odds Ratio = (Event with Inattention Frequency)(No Event with Attention) / (No event with inattention)(Event with attention)
When are odds ratios and relative risks used?
When calculating risk of rare events were an absolute risk cannot be quantified
Describe logistic regression
- Statistical model calculating Odds ratio
- Can include random effects variables – repeated measures
- More precise than crude odds ratio
What are two advantages of logistic regression over odds ratios?
- can include random effects variables (repeated measures)
- more precise
What two types of data are used to assess the frequency of a specific behavior?
- continuous data
- sampled data
Does continuous data calculate or estimate prevalence?
Calculates prevalence
Does sampled data calculate or estimate prevalence?
Estimates prevalence
What are three ways to calculate rates for specific behavior?
Frequency of a specific behavior divided by:
- hours traveled
- miles traveled
- number of observations
What are some statistical tests for estimating prevalence?
- chi-square
- regression
- logistic regression
What are three ways of assessing prevalence?
- Frequency of specific behavior
- Rate of specific behavior
- Statistical tests
What are some considerations in advanced product testing?
- In-vehicle technology can alter driver behavior in both positive (safe) or negative (unsafe) ways in field operational tests
- Can evaluate prevalence and or risk of these behaviors when systems are active vs inactive (baseline) to determine if in-vehicle system can improve safety
Why evaluate the prevalence of risk of safe and unsafe behaviors when systems are active vs inactive (baseline)?
To determine if in-vehicle systems can improve safety
