CEE 21 Quiz 2

As vehicle speed increases, does the coefficient of rolling resistance for road

vehicles operating on paved surfaces increase Proportionally?

Yes it does increase proportionately

True or False: For design and analysis purposes, the braking force on a vehicle is assumed to be the product of the sliding coefficient of friction on wet pavement and the perpendicular (to the road surface) component of gravitational force?

True

A dilemma zone at a traffic signal approach is an upstream section of roadway where the driver is too far away from the stop-line to safely continue and clear the intersection at constant speed at the end of a green phase, and is also…?

Too close to break safely in time

What (value) is the “perception-reaction time” used in designing a yellow change interval at a signalized intersection?

1 sec

In which orientation of the highway are horizontal curves viewed?

Plan view

What are four types of horizontal curves?

1. Simple circular

2. Compound 

3. Reverse

4. Spiral

On what side of the centerline are the centers of the two or more consecutive horizontal curves of a compound curve?

The same side

In what direction do the two consecutive horizontal curves of a reverse horizontal curve turn?

Opposite Sides

What is the purpose of banking (or superelevation) of horizontal curves?

Reduces side friction force on the vehicle

Does the minimum coefficient of side friction (fs) need to be less than, equal to, or greater than the maximum superelevation (emax) for year-round use, including under adverse weather conditions?

Greater than

With respect to the centerline of which lane is the traveled-path radius RV calculated from centrifugal force FC considerations for safe vehicle operation on a 2-lane highway horizontal curve?

Innermost lane

What is the Caltrans maximum allowed superelevation rate, emax, on 2-lane highways?

12%

For a given design speed Vd, as the superelevation rate e decreases, what happens to the minimum horizontal curve traveled-path radius RV required by Caltrans?

Increases

What does the deflection angle of the PI (Δ) of a simple horizontal curve give us? [what is it also known as]

Central angle

What is the name for the distance measured from the centerline of the inside lane of a roadway to an obstruction that must be visually cleared for sight distance?

Middle Ordinate

Along what is the length of a horizontal curves measured?

Center of roadway

What should horizontal alignment provide at all points on the highway (at least)?

 Minimum stopping sight distance

What must the distance from the middle of the inside lane of a horizontal curve to a lateral sight obstruction account for?

Stopping Sight Distance