ACTAR Roadway Analysis 4

Question 1

In roadway lighting analysis for a nighttime accident, which photometric quantity describes the luminous intensity per unit area of a surface as seen by an observer?

Accepted Answer

Luminance (cd/m²)

Answer

Luminance (cd/m²) measures the brightness of a surface as perceived by an observer, which is the relevant metric for visibility at night.

Question 2

A roadway has a posted speed of 55 mph. Using AASHTO stopping sight distance tables, what minimum sight distance is generally required on a level grade?

Accepted Answer

Approximately 495 feet

Answer

AASHTO 2018 Green Book specifies approximately 495 feet stopping sight distance for 55 mph design speed on a level grade.

Question 3

Which of the following best describes a 'gore area' in roadway design?

Accepted Answer

The triangular area between a through lane and a diverging exit ramp

Answer

The gore area is the triangular-shaped paved or unpaved area between the through roadway and a diverging ramp at an interchange.

Question 4

When analyzing a roadway cross-section, what is the typical maximum allowable superelevation for a rural highway in the US?

Accepted Answer

8%

Answer

AASHTO recommends a maximum superelevation of 8% for most rural highways, though 10% or 12% may be used in specific warmer climates without ice/snow.

Question 5

What does the 'tangent runout' portion of a superelevation transition accomplish?

Accepted Answer

It rotates the outside lane from normal crown to a flat (zero) cross-slope

Answer

Tangent runout rotates the adverse (outside) lane from its normal crown slope to a flat cross-slope, the first step before superelevation runoff begins.

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

(ACTAR) Accreditation Commission for Traffic Accident Reconstructionist Practice Test

ACTAR Roadway Analysis 4