Quiz #3

Which of the following are true statements about Vertical Curve Design?

I. Sight distance is typically more of a concern on Crest VCs, as opposed to Sag VCs

II. Headlight distance is typically more of a concern on Crest VCs, as opposed to Sag VCs

III. Drainage is typically more of a concern on Crest VCs, as opposed to Sag VCs

IV. Overhead clearance is typically more of a concern on Crest VCs, as opposed to Sag VCs

V. Passenger comfort is typically more of a concern on Crest VCs, as opposed to Sag VCs

A.) I

B.) I, III

C.) II, IV, V

D.) II, III, IV, V

No such thing as a 'Pasenger', question is withdrawn.

JMT said:

No such thing as a 'Pasenger', question is withdrawn.

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Doh! Fixed. Thanks JMT.

Is it B?

blondebedhead said:

Is it B?

Click to expand...

bbh, I appreciate the answer attempt. I was wondering why it took 60+ views and 5 days for someone to answer. But, unfortunately B is not correct.

Come on guys, this is right out of the GDHS.

I've been meaning to respond, super busy right now .... there is only one I am not positive on, leave it up until tomorrow

This one is actually quit easy. I know the answer, but I'll stay quiet for now.

Good question Ptatohed.

Not sure on 1 of them, but based on the answer combos, going with:

A

Nice job JQ. Yes, answer A. Sight dist on a crest VC is an issue because the cars may not be able to see "over the curve". Headlight dist is a concern in sag VCs because the headlights aim right into "g2" as opposed to straight down the roadway. Drainage is a concern on sag VC because water will collect at the low point on the curve. Overhead clearance can be a concern on crest VCs but it typically requires more consideration when designing sag VCs, particularly with regard to line of sight. Passenger comfort need only be considered for sag VCs since gravitational and centrifugal forces are combined/compounded in a sag curve. All this can be found in the GDHS, Chapt 3, vertical curve sections.

The overhead clearance one had me thinking for a bit, but ultimately common sense prevailed on this one (well and the answer choices) ..... but how often do you see crest VCs under and overhead obstruction?

I think the thing to keep in mind with the overhead clearance concern is the sight distance. An overcrossing can block a driver's line of sight in a sag condition but not a crest condition. See GDHS pgs 3-161 – 162.

Excellent, I didn't even think of that aspect.