Tuesday, April 24, 2012

Speed Humps on Mozart Street, Jamaica Plain

By: Jessica Lizza
Mozart Street, Jamaica Plain
http://g.co/maps/y522d
Overview

Mozart Street is a narrow, one-way local street in Jamaica Plain with parking on both sides. Vehicles driving along the street will encounter three speed humps.  A speed hump is one method of traffic calming to maintain speed control along local streets. Speed humps have a gentler profile than a speed bump does and cars may drive over them comfortably going approximately 15 mph. Speed humps are usually around twelve to fourteen feet. However the speed hump itself is not the only important factor. The spacing of speed humps along the road is also important in the effectiveness of the speed reduction. They should be placed approximately every 250-300 feet to keep speeds lower and prevent injury and damage to the vehicle.  The speed humps on Mozart Street, along with other traffic calming features of the street, are designed to achieve a road speed of about 20 mph. There is a desired low speed on this road due to the fact that it is a residential street that also has a grade school at the end of it with a playground across the street from it.

Speed Hump #1


When you turn on to Mozart Street from Lamartine Street you travel about 250 feet until you reach a stop sign when Mozart intersects Chestnut Ave. Right after you pass through this intersection, you are confronted with a sign alerting drivers of a speed bump ahead. However, this sign is incorrect because there is a speed "hump" ahead not a speed "bump".

Incorrect Sign trying to alert drivers
Shortly after the first sign, there is a barely visible "HUMP" painted on the road as yet another alert for drivers that they are quickly approaching the speed hump.While drivers are passing over this faded paint sign they can also observe a road sign that is also alerting them that they are right about to drive over a speed hump and to reduce their speed to 15 mph.  This speed hump is located about 200 feet after the stop sign.  This gives cars the opportunity to increase their speed to about 20 mph before hitting the speed hump.

Faded "HUMP" painted on the road approximately 20 feet from the speed hump.
Caution sign to alert drivers they are about to go over a speed hump.


1st Speed Hump
It is easy to observe from the picture above that from a distance without the signs on the side of the road a driver may not even know they are about to go over a speed hump. In addition, the speed hump they are about to drive over is not designed well enough to effectively reduce the cars speed. The cars are driving up a hill and do not slow down to 15 mph while driving over the speed hump. The grade of the speed hump is not steep enough, and drivers merely continue driving the same speed of approximately 20 mph. It is important to note that although the speed hump does not really force cars to slow down, due to its close proximity to the stop sign, cars are still going the desired street speed while going over the speed hump. Below is a link to a video showing cars driving over this speed hump:


http://youtu.be/Ed6UDRAOR7M


Speed Hump #2 : Placement


The second speed hump along the road is approximately 350 feet away from the first speed hump which is more than the preferred distance between two speed humps. However, the characteristics of the street itself prevent cars from going very fast, anyways. After the first speed hump there is a sizable hill which keeps cars speeds low, plus there is a fairly sharp curve to the right about 100 feet after the first speed hump, which paired with the narrow street and parking on both sides, manages to keep vehicle speeds low. 


Speed Hump #2 : Design


Once cars make it up the hill and around the turn they encounter a second speed hump. This speed hump could be said to be more important because it is right before a grade school pedestrian crossing. Sure enough, this speed hump is much more effective due to its larger height increase. 



A car driving over the second speed hump.
The link below shows a video of a car driving over this speed hump. In the video you can see that the vehicle reduces its speed and then gently drives over the hump at approximately 15 mph.


http://www.youtube.com/watch?v=AA6_4fInFmw&feature=youtu.be


Speed Hump #3:


The last speed hump has the same signs and postings as the other two. It is located approximately 150 feet away from the second speed hump which keeps the vehicle's speed nice and low. This speed hump (shown in the picture below) is not as dramatic as the second one, however the cars going over it are either still traveling slowly from the last speed hump, or turning onto the street, and therefore, also driving slowly. The speed hump is a raised pedestrian crossing, which you can tell by the zebra style painting, located about twenty feet before an intersection, so the speed hump was probably designed to keep the cars speed low while approaching the intersection and to help accomodate pedestrians. However, this speed hump does not have enough slope and therefore does not really force cars to slow down while going over it. 

Third speed hump serving as a raised crossing
It is interesting to note the catch basins in the picture above on either side of the raised crossing.  Placing a raised crossing on a street like this can interfere with drainage on that street, so an additional catch basin must be placed around the raised crossing to make sure that pools of water don't form and freeze over creating dangerous icy conditions in colder months.

Conclusion


The first two speeds humps need to have their markings repainted so that cars can see them better and take more caution. The first speed hump itself was not a good design because it was not large enough and cars could merely drive right over it at about 20 mph. There needs to be a longer sloped portion so that the speed hump may be higher which would force the cars down to 15 mph. The second speed hump was placed 350 feet from the first speed hump, however the natural design of the street helps to calm cars from picking up too much speed in between the two speed humps. The second speed hump itself was a good design with enough slope and height to slow cars to 15 mph. The third speed hump/raised crossing was a good distance of about 150 feet from the second hump, but like the first was too insubstantial and did not force cars down to 15 mph. Cars could easily drive over it at a speed of about 20 mph. In the end, though, the speed humps combined with the natural design of the road were effective to keep cars going about 20 mph throughout the street. 





4 comments:

  1. HI,
    I want to get nose surgery..I had accident when I was kid so I have hump in my nose and I want to do Hump Reduction . I am traveling India this summer and heard that it is cheap in Delhi, India so I want to do it there. Anyone knows how much does it cost and which surgeon or hospital is best?

    ReplyDelete
  2. Wow! There are way too many close calls and tragedies that could be prevented by drivers doing the right thing. Thanks for sharing your post!!
    Speed humps

    ReplyDelete
  3. Wow! There are way too many close calls and tragedies that could be prevented by drivers doing the right thing. Thanks for sharing your post!!
    Speed humps

    ReplyDelete
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