The Effects of Commercial Electronic Variable Message Signs ...

Method Ref. # Advantages Disadvantages
2.1.4 Responses: programmed
crashes; antecedent participant
and vehicle behaviors; can be
more frequent crashes
2.1.5 Scenario: contrived route,
artificial; unnatural vehicle and
environment; safe from harm
2.2 Non-simulator laboratory 87
2.2.1 Crash scenarios: movies,
pictures, acting out
2.2.2 Crash reconstructions:
questionnaires, focus groups
3.0 Safety Surrogate: Field 34, 85
3.1 Unobtrusive observation
3.1.1 Participant: random,
uncontrolled; usually unknown
3.1.2 Experimenter: usually
absent; remote observation;
unknown to participant
3.1.3 Stimuli: natural, ordinary,
in context; variable,
uncontrolled
3.1.4 Responses: crash
precursors; antecedent vehicle
behaviors; more frequent; few
participant variables
3.1.5 Scenario: natural route
and trip purpose; uses own
vehicle
3.2 Naturalistic driving
70 Some control over crashes;
can program more frequent
crash opportunities.
70 Control over driving
scenario; participant safe
from harm.
Relatively easy; less
resources.
Relatively easy; focus groups
more expensive.
55
Lack of negative consequences
can unnaturally alter frequency
of crashes.
Unnatural vehicle and
environment; artificial scenario;
simulator sickness.
Artificial, out-of-context testing
environment.
Artificial, out-of-context testing
environment; focus group social
biases.
15 No sampling bias. Do not know participant sample.
15 No artificial participant
behaviors due to
experimenter.
15 Natural stimuli. Stimuli not uniform; e.g.,
weather effects.
15 More frequent events than
crashes; can collect more
data with less risk.
15 Completely natural
experimental context; uses
own vehicle.
Crash precursors only indirect
indicators; insensitive to
participant variables.