Road and Pavement Inspection Flashcards

The Falling Weight Deflectometer (FWD) primarily evaluates:

Answer: Structural capacity and layer moduli of the pavement system

The FWD drops a weight to apply an impulse load and measures deflection basin data used to back-calculate layer moduli and remaining structural life.

Which type of pavement marking retroreflectivity measurement device is most commonly used by state DOTs for compliance with MUTCD requirements?

Answer: Retroreflectometer

Handheld or mobile retroreflectometers measure the retroreflectivity of pavement markings in mcd/m²/lux to ensure MUTCD minimum values are met.

Under AASHTO Pavement Design, the Structural Number (SN) is calculated using:

Answer: Layer thicknesses multiplied by their respective layer coefficients and drainage factors

SN = Σ(aᵢ × Dᵢ × mᵢ), where a is the layer coefficient, D is thickness, and m is the drainage coefficient for each pavement layer.

Which drainage feature along a roadway is inspected specifically to ensure it conveys water away from the pavement edge without undermining the shoulder?

Answer: Edge drain outlet

Edge drain outlets discharge subsurface water collected by edge drains; inspectors check for blockages, erosion at the outlet, and daylight pipe integrity.

Polished aggregate in pavement surface is a concern primarily because it reduces:

Answer: Surface friction and skid resistance

Traffic wear rounds and polishes coarse aggregate particles, reducing micro-texture and skid resistance, increasing crash risk especially in wet conditions.

When inspecting an unpaved gravel road, 'washboarding' is best corrected by:

Answer: Motor grading to re-establish cross-slope and apply fresh aggregate

Motor grading removes the rippled surface and restores proper cross-slope; adding fresh gravel may also be needed to rebuild lost aggregate.

The primary reason inspectors check pavement cross-slope (superelevation runoff) is to ensure:

Answer: Proper drainage of surface water to prevent hydroplaning

Adequate cross-slope (typically 1.5–2% for tangent sections) ensures surface water drains off the pavement quickly, reducing hydroplaning risk.