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 Committee Report

Committee Report #1


In City Council June 18, 2007

Councillor Craig A Kelley, Chair  
Councillor Henrietta Davis  
Vice Mayor Timothy J Toomey  

The Transportation, Traffic and Parking. Committee held a public meeting on Tuesday, May 15, 2007 at five o’clock and thirty minutes p. m. in the Sullivan Chamber.

The purpose of the meeting was to discuss the issues including speed bumps, raised intersections and other devices intended to slow traffic speeds, the limits of employing these devices and the criteria for selection of the placement of these devices.

Present at the meeting were Councillor Craig Kelley, Chair of the Committee, Councillor Henrietta Davis, Sue Clippinger, Director, Traffic, Parking and Transportation, Owen O’Riordan, City Engineer, Katherine Watkins, Senior Engineer, Public Works Department, Juan P. Avendano, Traffic Calming Project Manager, Community Development Department (CDD), Cara Seiderman, Transportation Planner, Environmental and Transportation Division, CDD and Donna P. Lopez, Deputy City Clerk.

Councillor Kelley opened the meeting and stated the purpose.  He stated that he gets asked about raised devices all the time and would like to have this report contain all the pertinent information about speed bumps and raised devices that could be provided to a resident when there is a question about these devices.

At five o’clock and thirty-two minutes p. m. Councillor Kelley opened the meeting to public comment.

Kathy Podgers, 148 Pearl Street, stated that she is a trained compliance person who started Citizens for Feasible Compliance and that she is concerned about pedestrian safety issues as well as cyclist safety.  She said that the zigzag traffic pattern on an Area IV street causes consternation, especially at night with headlights.  She said that speed bumps are effective in parking lots but cause accidents when placed elsewhere.  She does not want city streets used as major thoroughfares.  Traffic lights and flashing yellow light work better thought lights might bother residents by going on and off all the time, though we all have to sacrifice something.  Raised crossing are good at locations such as schools or senior housing developments.  She suggested that signs be installed before raised crossings as a notice to motorists so they do not hit them too fast.  A raised device at Erie and Brookline Streets is needed to enable people to catch the 47 bus.  Erie and Pearl Streets should also have a raised device.  She spoke about solving multiple issues at the same time and getting good value for the money spent on the solution in that one raised intersection could handle the need for up to 8 curb cuts on the sidewalks.  She concluded that the solution should fit the situation.

Dennis Wolkoff, 20 Lowell Street, supported the city’s effort to enforce traffic calming.  It is an important topic and he and his neighbors like the idea of traffic calming.  He suggested people see the movie “Contested Streets” about how traffic calming has worked in other places.  Lots of streets in Cambridge should only be used by people who belong there.

At five o’clock and forty-five minutes p. m. Councillor Kelley closed public comment.

Councillor Davis asked for an explanation of raised devices.

Juan P. Avendano, Traffic Calming Project Manager, explained the main reason for raised devices is to reduce speed, to make the crossings safe for pedestrians and to make the pedestrians more visible.  Raised devises are located in areas where there are a large number of pedestrians crossing the street.  He distributed a map that outlined the locations of traffic calming projects completed and planned including raised crosswalks or intersections.  Councillor Davis asked what is the difference between a raised device and a speed bump.  Mr. Avendano responded that a speed bump is used to reduce speed and is a bump in the roadway.  Raised devices improve pedestrian safety, make pedestrians more visible and reduce the speed of cars. They are located at a crosswalk or an intersection.

Sue Clippinger stated that there are two kinds of raised devices.  They are raised crosswalks, which is just a raised crossway across the street and raised intersections, where the entire intersection is raised.  The design of raised intersections is dependent on the slope of the sidewalk.  The guideline used is a seven percent (7%) slope for all raised devices. 

Councillor Davis asked if they are made of the same material.  Mr. Avendano stated that slopes used as ramps are bituminous.  White triangles are used as warnings for raised devices on the slopes.    Pavers are used on the top, flat portion of the raised crosswalk or intersection.  Granite curbs are used around raised devices.  The sidewalk edge of a raised device is marked so that vision-impaired people will know that the sidewalk has ended and the street, albeit in a raised fashion, has begun.  Signage posts the appropriate speed for the raised devices and is located 100-150 feet before raised devices.  If an automobile is damaged because of a raised device the first question asked is what was the speed traveled.

Councillor Davis asked what determined the width of the device.  The width used is the crosswalk width which is ten feet wide; width of a raised intersection is based on the width of the street.  Are snow plows and fire equipment accommodated by raised devices asked Councillor Davis?  Mr. Avendano responded in the affirmative.  Ms. Watkins informed the committee that the snow manual is given to drivers who do the snow routes.  The snow manual contains the locations of the raised devices.  The Fire Department reviews the raised devices to ensure that the device does not impede the fire apparatus. The department also identifies locations that may be problematic for the placement of raised devices based on response routes and times.

Sue Clippinger stated that other communities do not always receive the high level of cooperation that Cambridge receives for their traffic calming program from the Public Works, Fire and Traffic, Parking and Transportation Departments.

Councillor Kelley asked how locations are chosen for raised devices.  The Putnam School parents would like a raised device installed, he said.  Ms. Watkins informed the committee that the fire department had an issue with the installation of a raised device on Putnam Avenue.  Mr. O’Riordan added that traffic calming is not generally considered unless there is construction project proposed on a given street or in a particular area of the city, thus maximizing the cost benefit associated with these projects. Mr. Kelley noted that there are many raised devices by the King Open School, though none are on busy Cambridge Street.  The King Open School (the Harrington School at the time) area was the first major traffic calming project in Cambridge, stated Ms. Seiderman.  The program has since evolved.  The initial focus for traffic calming is on construction schedules, not necessarily on where a school is located, although school locations generally get highest priority when there is nearby construction happening.  Many raised devices have been put in by non-City entities as part of mitigation for a large project requiring a special permit.  Harvard University did mitigation for Oxford Street and paid for the raised devices on Oxford Street, stated Ms. Clippinger.  MIT construction on Vassar Street will create one raised intersection on Vassar Street.  Novartis paid for the raised intersection on Sidney Street at Putnam.  There is no raised device for the ongoing project on Mt. Auburn Street, stated Councillor Davis.  Ms. Clippinger stated that the Holmes Trust did the Green Street device through mitigation.  The raised device at Cedar Street and Dudley Street in North Cambridge was unique in not being connected to anything else.  All the other non-mitigation raised devices were part of City-funded road work.

Ms. Clippinger stated that the City does not do speed bumps because they’d rather kill two birds with one stone by enhancing pedestrian access and crossings as well as reducing speeds.

Councillor Davis stated that she has received e-mails from residents on Middlesex Street regarding traffic calming.  She submitted the e-mail for the report (ATTACHMENTS 1-11).  This street is on the chapter 90 list and the city process will start next month, stated Mr. Avendano.

Councillor Kelley asked why there are no speed bumps on Middlesex Street.  Mr. Avendano urged caution about installation of speed bumps.  Speed bump noise is annoying.  Other issues with speed bumps are drainage and city environment.  Speed bumps cost money.  Equity is also an issue; all street users are considered.  Raised devices are the most aggressive treatments and have the strongest impact and are installed where most critical such is in high pedestrian traffic areas, stated Ms. Seiderman, who also stated that everything is in the context of street work.  Other communities have run into problems with willy-nilly putting in speed humps.  There are equity issues and noise impacts, but also impacts for various street users because if a raised device is highly used by pedestrians, people understand why it is there and are aware of it.  But if the raised device is just placed on the street with no obvious reason, a lot of people in and around the area will have trouble understanding its location and will not like it.  Plus, the Fire Department does not want a lot of speed bumps just anywhere.

Councillor Kelley raised another concern about raised devices - that of reducing parking spaces.  Ms. Clippinger stated that it is illegal to park within twenty feet of the corner.  High parking demand streets have cars parked at the corner but the fact that cars park there does not make the spaces legal, so oftentimes a raised device is actually only impacting these illegal, though used, parking spaces.  These devices become enforcement devices for eliminating illegal parking.  Sometimes, though, a raised device can remove legal parking spaces, when it is placed at a mid-block location.  There is no parking on raised devices stated Mr. Avendano.

Councillor Kelley asked why there are no raised crosswalks on major streets.  Ms. Clippinger responded that raised crosswalks are not installed on major streets because of the nature and volume of traffic on these streets.  Ms. Seiderman added that there are no cities she is aware of that permit raised devices on major streets.

Councillor Kelley asked how different is it to cut the curb for an accessibility ramp.  Ms. Clippinger stated that raised devices are not disability ramps.  Councillor Kelley asked how difficult is it to install a raised device.  Mr. Avendano stated that the roadway needed to be in perfect condition and that building a raised device is more complex than it seems.  Catch basin and drainage are issues that are reviewed.  Mr. O’Riordan stated that raised devices can have a major impact on drainage that they can act as dams from the perspective of impeding surface flow, which is sometime integral and critical to storm water management on city streets.  Devices must be built to the same elevation as the adjacent sidewalk and the sidewalk itself may need to be reconstructed so as to provide adequate elevation and sidewalk access adjacent to the raised device.  At least six inches of reveal, curb showing above the street, is needed to provide an approach ramp with the correct road slope as one drives onto the device.  Conditions to ensure that the pavers will not settle must be reviewed.  Interlocking pavers are used and must sustain significant vertical and lateral stresses associated with vehicular loads and turning movements and they are also boxed in with substantial granite curbing on all four sides to prevent shifting or movement. 

A discussion ensued about marking raised devices.  Ms. Seiderman stated that there are different ways to mark crosswalks.  Cambridge uses zebra markings.  Crosswalks are designated by white lines.  Yield to Pedestrian signs are being considered.  Ms. Clippinger stated that an analysis of habits at crosswalks is being conducted.  The Traffic, Parking and Transportation Department are trying to determine whether there is insufficient yielding being done by motorists.  A Yielding Study would be done for the Oxford Street raised devices.  She stated that markings will be done in July with the start of the new fiscal year, as the Department has spent all of its money for this year.

Mr. O’Riordan stated that there are no problems with snow plowing as the operators are familiar with their routes and the snow manual.  The predicted location of raised devices makes it easier for drivers to adjust plows.  Speed bumps would be more difficult for plow drivers to accommodate, and a plow can do a lot of damage to a raised device if the operator does not adjust the plow beforehand.

Councillor Kelley asked the cost of raised devices.  Mr. Avendano responded $75,000 - $120,000 on top of street work, to include catch basins and drainage issues.  The cost of raised devices mostly comes out of the City’s traffic calming budget.  Mr. O’Riordan commented that traffic calming is considered for every street reconstruction project, but it is not always appropriate.  Reconstruction is typically at least a grind and overlay project before traffic calming is considered.  The traffic calming process takes 6-9 months to resolve.  The street reconstruction projects and traffic calming requests are reviewed and the needs are matched, stated Ms. Seiderman.  She added that resources are used where there is a critical need.  A public process may not be as involved if street reconstruction suddenly happens and the 6-9 month process cannot be met.  Mr. Avendano stated that he keeps track of where people have asked for traffic calming to match against upcoming work.  If no one has asked for traffic calming and certain things do not make sense, there may not be a traffic calming discussion, but the City may still do basic pedestrian things like put in curb cuts or try to set up sight lines that make sense.

City staff than summarized other aspects of traffic calming as being crossing islands, chicanes, visual narrowing through striping and curb extensions, most of which happen only with street reconstruction.

Councillor Kelley asked the cost for a bump out.  Mr. O’Riordan gave the following information:

            $6,000 - $10,000                     for drainage

            $5,000 - $10,000                     for curb work

            $20,000 - $35,000                  estimated average total cost.

This cost is paid by the Public Works and Community Development Departments. 

Mr. O’Riordan stated that the city’s five year plan will outline where street and sidewalk work will be proposed, but noted that the five year plan was subject to significant change as circumstances dictate so no one should expect the City to follow it absolutely.  Some of the issues that need to be borne in mind when considering a 5 year street and sidewalk  reconstruction plan are the unpredictability of state funds, utility repair and replacement work, development in the city, increased truck activity, variable asphalt and concrete costs and some unpredictability associated with street condition reduction rates. 

Councillor Kelley thanked all attendees.

The meeting adjourned at six o’clock and fifty-five minutes p. m.

For the Committee,


Councillor Craig Kelley, Chair

 Transportation, Traffic and Parking Committee


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