ACTAR Visibility & Lighting Conditions 3

Question 1

Under FHWA minimum retroreflectivity guidelines, what is the minimum retroreflectivity level for white pavement markings?

Accepted Answer

100 mcd/m²/lux

Answer

The FHWA minimum retroreflectivity standard for white pavement markings is 100 mcd/m²/lux, below which markings may be inadequate for safe nighttime travel.

Question 2

In a nighttime pedestrian collision reconstruction, 'recognition distance' differs from 'detection distance' in that:

Accepted Answer

Detection distance is where the object first becomes visible; recognition distance is where the driver can identify what the object is

Answer

Detection distance is where the driver can first see an object, while recognition distance is the closer distance at which the driver can identify it as a specific hazard, allowing for appropriate response.

Question 3

Koschmieder's law is applied in accident reconstruction to:

Accepted Answer

Determine the visibility distance in foggy, smoky, or hazy atmospheric conditions

Answer

Koschmieder's law defines the relationship between the atmospheric extinction coefficient and the maximum visibility distance in conditions such as fog, smoke, or heavy rain.

Question 4

A reconstructionist analyzing 'adverse lighting conditions' would consider which of the following as a significant factor in driver visual performance?

Accepted Answer

The dark adaptation state of the driver's eyes when transitioning from bright to dark environments

Answer

Dark adaptation—the process by which the eyes adjust to reduced illumination—significantly affects driver visual performance; a driver transitioning from bright to dark conditions may have reduced nighttime vision for several minutes.

Question 5

What effect does a wet road surface have on the retroreflectivity of pavement markings at night?

Accepted Answer

It decreases retroreflectivity because a water film prevents light from reaching retroreflective beads

Answer

A wet road surface covers the retroreflective glass beads embedded in pavement markings with a water film, significantly reducing or eliminating retroreflectivity and making markings much harder to see at night.

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

ACTAR Visibility & Lighting Conditions 3