It is clear B..

what are we looking for - identify a serious drawback

Enforcement of local speed limits through police monitoring has proven unsuccessful in the town of Ardane. In many nearby towns, speed humps (raised areas of pavement placed across residential streets, about 300 feet apart) have reduced traffic speeds on residential streets by 20 to 25 percent. In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.

Which of the following, if true, identifies a potentially serious drawback to the plan for installing speed humps in Ardane?


A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit.
It rather gives a reason for humps

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps.
This is a serious drawback and there is no way to overcome it. Remember we are looking for a drawback, not looking to strengthen or weaken argument

C. The residential speed limit in Ardane is higher than that of the nearby towns where speed humps were installed.
not a drawback

D. Motorists who are not familiar with the streets in Ardane's residential districts would be likely to encounter the speed humps unawares unless warned by signs and painted indicators.
Trap... Yes it is a problem but there is a solution in the choice itself .. - warn by signs and painted indicators

E. Bicyclists generally prefer that speed humps be constructed so as to leave a space on the side of the road where bicycles can travel without going over the humps.
Not a drawback. Most have small area left on sides of humpfor cycles.


B

NEW question from GMAT® Official Guide 2019

(CR04925)
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here is my reasoning

A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit.

this option favors installation of humps, so A is out

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps.

this one is the most logical answer choice since we talk about installing humps that limit speed, it will definately be a problem for emergency vehicles just imagine an ambulance driving at a speed of 150mph, emergency pizza delivery in 10 minutes

C. The residential speed limit in Ardane is higher than that of the nearby towns where speed humps were installed.

this option gives information that speed in Ardane is higher. that means it strengths the initiative of installing humps, hence C is out

D. Motorists who are not familiar with the streets in Ardane's residential districts would be likely to encounter the speed humps unawares unless warned by signs and painted indicators.

this one doesnt give reason to not install humps, there will always be motorists unaware of humps everywhere in the world moreover the main topic isnt about motorists and painted indicators, we are concerned about speed limit d humps hence D is out

E. Bicyclists generally prefer that speed humps be constructed so as to leave a space on the side of the road where bicycles can travel without going over the humps.

this option is totally irrelevant , do we talk about Bicyclists ? no ! its about cars and speed limit hence E is out

A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit. - strengthens. Incorrect.

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps. - irrelevant.

C. The residential speed limit in Ardane is higher than that of the nearby towns where speed humps were installed. - irrelevant.

D. //Motorists who are not familiar with the streets in Ardane's residential districts would be likely to encounter the speed humps unawares// ((unless warned by signs and painted indicators.)) - though first part might lead to something like it poses danger etc.; however, the second part makes it weird and kinda irrelevant. According to the second part the plan would be ok, if indicators are put. But, the argument doesn't say they won't put an indicator or vice versa. So it is a strengthener and also irrelevant.

E. Bicyclists generally prefer that speed humps be constructed so as to leave a space on the side of the road where //bicycles can travel //without going over// the humps.// - this casts a doubt whether the plan will succeed as the bicyclists might misuse it and chance of accidents would still exist and road safety is not guaranteed in this way.

Thus, to me E is best.

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I think this is B.Talking about safety.If ambulances and firefighters arrive late then there is danger to life.I thought this was straightforward.Or I am horribly wrong and need to do some brain rewiring.

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Enforcement of local speed limits through police monitoring has proven unsuccessful in the town of Ardane. In many nearby towns, speed humps (raised areas of pavement placed across residential streets, about 300 feet apart) have reduced traffic speeds on residential streets by 20 to 25 percent. In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane’s transportation commission plans to install multiple speed humps in those neighborhoods.

Which of the following, if true, identifies a potentially serious drawback to the plan for installing speed humps in Ardane?

A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit.
B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps.
C. The residential speed limit in Ardane is higher than that of the nearby towns where speed humps were installed.
D. Motorists who are not familiar with the streets in Ardane’s residential districts would be likely to encounter the speed humps unawares unless warned by signs and painted indicators.
E. Bicyclists generally prefer that speed humps be constructed so as to leave a space on the side of the road where bicycles can travel without going over the humps.


Analysis
Question Type: Weaken
BID (Boil It Down): Bumps reduce speed, so we should have bumps to enhance safety.

Big 3 GMAT Assumptions:
1. Success (the plan is likely to work) - Installing the speed humps will not have serious negative consequences.
2. Relevance - N/A
3. No Other Factors - N/A

Goal: Undercut the notion that the new humps will generate an improvement in safety/point out a significant downside of the humps.

Choice B is correct. Though traffic might be slowed considerably, slowing emergency vehicle down to a stop is obviously a negative consequence if the objective of the plan is to ENHANCE SAFETY. This option certainly doesn’t crush the plan, but it does raise a substantial drawback to the plan’s goal of enhancing safety. Reducing emergency response time could be a pretty big freaking problem for safety.

Choice A does not tell us anything new about the lack of wisdom of installing the humps. We already know there Ardane has a speeding problem.

Choice C makes an irrelevant comparison. Test-takers are attracted to this distraction option because people picture drivers more likely to possibly lose control/crash if they are driving faster (higher speed limit). However, even if the speed limit in Ardane were higher than in neighboring towns, installing the humps could and would likely reduce speeding (maybe improving safety even more dramatically). This option certainly doesn’t detract from the wisdom of installing humps. In fact, it could very well be the case that the speed humps could mean an even greater enhancement to safety in light of the higher speed limits.

Choice D would only be a drawback if there were no signs, but of course there could be. We don’t know that Ardane is even contemplating not installing signs, so this option doesn’t have any clear negative force on the plan.

Choice E has absolutely zero impact on the plan. Having spaces on either side on the humps for bicycles may or may not be done, and whether it is or isn’t has no clear impact on the safety outcome of the plan. Dump it.

B
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Enforcement of local speed limits through police monitoring has proven unsuccessful in the town of Ardane. In many nearby towns, speed humps (raised areas of pavement placed across residential streets, about 300 feet apart) have reduced traffic speeds on residential streets by 20 to 25 percent. In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.

Which of the following, if true, identifies a potentially serious drawback to the plan for installing speed humps in Ardane?

Boil it down - In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.

C'-- In order to reduce traffic speed/bring traffic speed within the speed limit and thereby enhance safety in residential neighborhoods, Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.
If the conclusion was C' as specified above, will A be valid weakener ? -- Since even with speed humps, the traffic speed will not be within the speed limits .


A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit.

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps. -- Correct

mcelroytutoring , AjiteshArun , GMATNinja , mikemcgarry , egmat , sayantanc2k, RonPurewal , DmitryFarber , MagooshExpert , ccooley , ChiranjeevSingh, GMATGuruNY , KarishmaB , other experts-- please enlighten
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No. Even with your conclusion, option A will not be weakener. For the following reason:

Let x be the speed limit. If many vehicles drive at 1.25x and we bring down their speed by 20-25%, their new speed will be 0.94x to 1.0x. Thus, their new speed will be within the speed limit.

- Chiranjeev
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Dear MikunDash,

I'll try to answer your query. kindly follow.
Read the question stem carefully.

Enforcement of local speed limits through police monitoring has proven unsuccessful in the town of Ardane. In many nearby towns, speed humps (raised areas of pavement placed across residential streets, about 300 feet apart) have reduced traffic speeds on residential streets by 20 to 25 percent. In order to reduce traffic speed and thereby enhance safety in residential neighborhoods, Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.



The author wants us to answer with the potential serious drawback to the plan for installing speed humps in ARDANE. Author isn't concerned about the drawbacks in the neighbouring cities. Only concern is Ardane.
I hope this is in itself enough to actually eliminate your query, but if you still need further reinforcement.

The author says that Ardane's transportation commission plans to install multiple speed humps in those neighborhoods.
Multiple jumps off to me from this sentence, may be the neighbouring city didn't install multiple speed humps, hence may be the draw back in the neighbouring city aren't as severe as in Arden.

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps.

Just addressing C because it is the second most choose answer option. Also to answer adkikani, "if same could be avoided by more precise reading."
Yes, more precise reading may help you eliminate C. As follows:

Even if residential speed limit in Arden is higher than that of the nearby towns where speed humps were installed. This isn't the potential serious drawback of having speed humps in Arden.

If we read the question carefully, the question mentions potentially serious draw back.

Speed limit is already existent, and potential serious drawback is yet to occur.

I hope this helps us eliminate this answer option as a clear non-contender.

GMATNinja please provide why C is not a drawback in the argument ??

According to the passage, Ardane’s transportation commission develops a plan to install speed humps “in order to reduce traffic speed and thereby enhance safety in residential neighborhoods.” The question asks that we identify a drawback to that plan. Consider (C):


If speed humps effectively reduced traffic speed where speed limits were lower (and drivers were presumably driving slower), then similar speed humps will almost certainly reduce driving speeds where speed limits are higher (and drivers are presumably driving faster). This means that the plan is very likely to achieve its goal of reducing traffic speeds.

(C) would require far too many assumptions and far too much additional information to even hint at a drawback. For example, some may argue that the plan could potentially reduce traffic speeds too much, but we have no information to indicate by how much the speed limit in Ardane differs from that of nearby towns. If the residential speed limit is merely 5 mph higher, then any negative impact on the flow of traffic will likely be negligible. Therefore, (C) does not indicate a drawback, and we can eliminate it.

I hope that helps!
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Our ask is to find a flaw in the plan of installing humps. Why is there a need of installing humps --> To reduce speed & enhance safety.

How on earth does slowing down ambulances and emergency vehicles' indicates a flaw in the plan? Ok, I'll agree that the speed got reduced. What about enhancing safety?

What about bikers? They are failing both the objectives of the plan:
1. No speed is reduced as stated in the passage -- Unaware
2. Safety is at risk.

Even if we assume that the emergency vehicles have the potential to enhance safety. Aren't we assuming way too much?

GMATNinja or any experts, please help.
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It's important to notice the exact language of the question -- here, we are not asked to find a flaw in the logic of the plan. Instead, we have to identify a "potentially serious drawback" to installing speed humps. (Side note: do people actually call these speed humps? I've always heard speed bumps. )

So we don't specifically need to determine why the humps would not reduce speed or increase safety. We're looking for ANY potential drawback to installing speed humps in the town -- maybe speed humps severely damage the bottoms of cars, or maybe thieves wait in the woods and carjack people who slow down at the speed humps. There doesn't HAVE to be a connection between the "drawback" and the intended goal of installing the speed humps.

With that in mind, consider (B):

This is a serious drawback! Emergency vehicles need to move quickly to put out fires and get injured people to the hospital. If the vehicles have to slow down almost to a stop, then the town of Ardane might, on the whole, suffer if the plan to install speed humps is implemented.

(B) identifies a drawback to installing speed humps, so it's the correct answer.

Take another look at (E):

(E) tells us about what kind of speed humps would be preferred by bicyclists. But it doesn't tell us that this kind of speed hump will actually be installed. So we really can't conclude that (E) gives us any information that would impact speed or safety.

In addition, even if the speed humps with space on the side ARE installed, (E) still doesn't identify a serious drawback to installing speed humps. Maybe these speed humps are slightly less effective at reducing speed than other speed humps would be, but overall, the speed humps would still be somewhat effective and there isn't really a downside to installing them.

(E) is out because it doesn't identify a serious drawback to installing speed humps.

I hope that helps!
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This is a big "what?" for me. As if ambulances and firefighters are not driving in the neighbourhoods of nearby cities too? If it worked in nearby cities, why wouldnt it work here?

although i choose B , but I had similar doubt on B .
Then i read the question:
Which of the following, if true, identifies a potentially serious drawback to the plan for installing speed humps in Ardane?
it is true that installing these speed humps would bring a disadvantage to emergency vehicles.
But my doubt prevails, what is so different in Ardane as compared to neighborhood towns? No such information is given in the argument that can distinguish it.

VeritasKarishma GMATNinja: Could you please clarify on this thought? Why shall we not bother about comparison?
If we can learn lesson of speed humps can help to reduce speed why not take consider disadvantage of stopping of emergency vehicles in other towns. It's not they may not have these vehicles.

please suggest.

Local speed limits are not being enforced.
In nearby towns, speed humps have reduced traffic speeds by 20-25%.

Plan: Ardane plans to install speed humps in residential neighbourhoods.
Aim: To reduce traffic speed and thereby enhance safety in residential neighbourhoods

Which of the following, if true, identifies a potentially serious drawback to the plan?

A. On residential streets without speed humps, many vehicles travel at speeds more than 25 percent above the posted speed limit.

This point is in favour of installing speed humps.

B. Because of their high weight, emergency vehicles such as fire trucks and ambulances must slow almost to a stop at speed humps.

This identifies a serious drawback to the plan and needs to be addressed. The aim is to improve the safety of residents. If emergency response vehicles will face a problem because of speed humps, it is a potential drawback. Other towns have speed humps does not mean that this was not identified and addressed by them (e.g. making side roads for emergency vehicles etc). Also, perhaps other towns had other aims. Safety may not have been priority - we don't know. The point is - just because something exists somewhere else and does what it is supposed to, doesn't mean it does not come with its own problems which need to be mitigated.
Note that we are looking for an option that identifies a serious drawback. The plan may reduce speed limit in the area but what problem does it come with?
Pay special attention to the way your question stem is worded.

C. The residential speed limit in Ardane is higher than that of the nearby towns where speed humps were installed.

Irrelevant.

D. Motorists who are not familiar with the streets in Ardane's residential districts would be likely to encounter the speed humps unawares unless warned by signs and painted indicators.

We don't know whether speed humps are made with signs and indicators or without. So we don't have enough information to say whether this is a potential drawback.

E. Bicyclists generally prefer that speed humps be constructed so as to leave a space on the side of the road where bicycles can travel without going over the humps.

What bicyclists prefer is irrelevant.

Answer (B)
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The question asks us to find a potentially serious drawback. As explained in this post, (B) does exactly that!

As for the nearby towns: all we know about these towns is that they installed the speed humps and successfully reduced the speed of traffic in residential areas. Perhaps they didn't think about the issue with the emergency vehicles, and they deeply regret installing the humps. Or perhaps they did know about the issue with the emergency vehicles, and decided that despite this serious drawback, it was still worth it to install the humps. Or perhaps they have lighter emergency vehicles, and this isn't an issue at all! We have no idea, and honestly the answer is irrelevant. (B) gives us a potentially serious drawback to installing the humps in Ardane, so (B) is the correct answer.

I hope that helps!
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I realize that the question asks for a "potentially serious drawback to the plan for installing speed humps." To clarify, does the drawback that we need to identify have to directly attack the reason behind why the commission wants to install the speed humps to 1. reduce traffic speed or 2. enhance safety.

Or theoretically could you have identified a more general reason as to why there are significant drawbacks to speed humps (e.g., they are super expensive)?

The question "a potentially serious drawback to the plan" is vague, but I realize on critical reasoning questions that you normally need to attack the logic/the correct answer does this by tackling one of the issues for the speed humps --> safety.

As we explained in this post, we're looking for ANY serious drawback to the speed humps. That drawback might directly relate to the commission's reasons for wanting the humps, or might not.

You really can't generalize about all CR questions -- you just have to take each one as it comes. Other CR questions might ask you to undermine (or strengthen, etc) an argument, and that could involve weakening the author's chain of logic.

This question doesn't ask you to do that, and there's no "rule" that you have to undermine the commission's reasoning. You just have to find a drawback to the speed humps, which is provided in option (B).

I hope that helps!
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