ROAD SAFETY AUDIT Granite Avenue at Interstate 93 Ramps Town of Milton May 22, 2017 Prepared for: MassDOT Prepared by: Toole Design Group 2 Oliver Street, Suite 305 Boston, MA 02109
Table of Contents Background... 1 Project Data... 1 Project Locations and Description... 2 Roadways... 4 Intersections... 4 Audit Observations and Potential Safety Enhancements... 5 Study Area-wide... 6 Granite Avenue at Courtland Circle... 8 Interchange South: Granite Avenue at I-93 NB on-ramp and I-93 NB off-ramp... 10 Interchange North: Granite Avenue NB at I-93 SB off-ramp and 2 Granite Avenue Driveway; Granite Avenue SB at I-93 SB on-ramp and I-93 SB off-ramp... 12 Summary of Road Safety Audit... 15 List of Appendices Appendix A. Appendix B. Appendix C. Appendix D. RSA Agenda RSA Audit Team Contact List Detailed Crash Data Road Safety Audit References List of Figures Figure 1: Locus Map... 3 Figure 2 Sidewalks end at Courtland Circle on the eastern side of Granite Avenue, and existing sidewalks are in poor condition.... 6 Figure 3 - Cyclists are required to merge across high speed traffic on large on- and off-ramps without any dedicated facilities, pavement markings, or signage.... 7 Figure 4 - Motorists often turn left into Courtland Circle before turning around and making a right to access I-93 NB...... 9 Figure 5 Granite Avenue NB on-ramp queuing during peak hour congestion, as viewed from the Courtland Circle intersection looking south.... 10 Figure 6 Motorists often perform uncontrolled U-turns from Granite Avenue NB to Granite Avenue SB. 12
List of Tables Table 1: Participating Audit Team Members... 2 Table 2: Estimated Time Frame and Costs Breakdown... 15 Table 3: Potential Safety Enhancement Summary... 16
Background Toole Design Group (TDG) conducted an RSA along Granite Avenue between Interstate (I)-93 southbound on- and off-ramps and Courtland Circle in Milton, MA near the City of Boston line at the Neponset River. The study area for the RSA was selected due to 2012-2014 Highway Safety Improvement Program (HSIP) High Crash Clusters located on Granite Avenue near the I-93 Ramps, indicating that the location falls within the top 5% of high crash locations within the Metropolitan Area Planning Council (MAPC) area. The RSA was initiated due to an upcoming reconstruction project along Granite Avenue from the southeast expressway ramps near the Neponset River extending south to Squantum Street. The goal of a Road Safety Audit (RSA) is to identify safety issues and provide ideas for potential enhancements to improve safety for all roadway users. The potential safety enhancements are categorized by cost and timeframe, which helps responsible agencies to determine if, and when to make proposed implementations. Enhancements are categorized as short-, mid- and long-term and low, medium and high cost. The RSA included a discussion of safety issues and gathering input on potential short-, mid-, and longterm safety improvements for the study area. Project Data The audit team participated in the RSA for Granite Avenue at the I-93 Ramps area on Wednesday, April 5, 2017. The audit was held at Milton Town Hall at 525 Canton Avenue, Milton MA and included a site visit to the study area. As indicated in Table 1, the audit team consisted of representatives from the Town of Milton, the Milton Police Department (MPD), the Milton Fire Department (MFD), MassDOT Traffic Engineering & Safety, MassDOT District 6, Central Transportation Planning Staff (CTPS), the Milton Bike Committee, and the consultant team for the reconstruction project. As part of the audit, the group also observed operations and safety at the study area. This report documents the audit team s findings after discussion and observation. The RSA agenda can be found in Appendix A. Contact information for the team members can be found in Appendix B. Prior to the RSA, the team received collision diagrams and crash detail summaries based on crash narratives supplied by the MPD for the years of 2012 through 2015. Appendix C provides the detailed crash data for the study area. During the audit, the team first met at Milton Town Hall and reviewed the collision diagrams and crash detail summaries, and discussed safety issues in the project area. The team discussed common traffic patterns and desired routes that could be contributing to the high-crash concentration clusters in the area. The team also discussed the lack of bicycle and pedestrian infrastructure, and the challenges and opportunities to improve safety. Although there were low number of bicyclists and pedestrians observed using the corridor, Granite Avenue is a desired route from Milton to the Neponset River Greenway and points north toward Dorchester and other Boston neighborhoods. After discussing the safety issues, the team visited the I-93 Granite Avenue interchange to observe conditions in the study area. Following the discussion of safety issues and the site visit, the team reconvened in Milton Town Hall to discuss potential safety enhancements in the study area. Page 1
Table 1: Participating Audit Team Members Audit Team Member Agency/Affiliation Mark Alba Michelle Deng Elsa Chan William Clark Chris Trudel John Thompson Lee Toma Chen-Yuan Wang Rob Ballasty Jack Grant Geri Vatan Courtney Dwyer Jeff Parenti Jessica Mortell Preston Buehrer Milton Police Department MassDOT Traffic Safety MassDOT Traffic Safety Milton Planning Department Milton Department of Public Works Milton Department of Public Works Milton Bike Committee CTPS/ Boston Region MPO MassDOT Traffic Operations Milton Fire Department MassDOT D6 MassDOT D6 Nitsch Engineering Toole Design Group Toole Design Group Per the crash data summary provided by the MPD, 40 crashes were reported within the project area from 2012 to 2015. There was one fatal crash involving a motorcyclist. Approximately 80% of the crashes involved multiple vehicles, 20% of the crashes involved only a single vehicle, and none of the crashes involved bicyclist or a pedestrian. The most common type of crash was rear-end crashes (55%) with singlevehicle and angle crashes each representing 20% of all crashes. Crashes were fairly distributed throughout the week and throughout the year. Most crashes occurred during the peak hour periods (30% from 6AM to 10AM and 30% from 2PM to 6PM), and most crashes occurred during dry (75%) and daylight (70%) conditions. Project Locations and Description This RSA study area included Granite Avenue between I-93 southbound (SB) on- and off-ramps near the Town of Milton and City of Boston limits at the Neponset River to the north, and Courtland Circle to the south. Counts from 2015 taken at the City of Boston line show that Granite Avenue serves approximately 45,000 vehicles per day, while counts from 2016 taken at the Courtland Circle intersection show that Granite Avenue serves approximately 20,000 vehicles per day. 1 The study area is shown in Figure 1, and described on the following pages. 1 Counts from MassDOT s Transportation Data Management System Page 2
Figure 1: Locus Map Page 3
Roadways Granite Avenue runs north-south through the project area with its northern terminus at Gallivan Boulevard in the City of Boston and its southern terminus at Willard Street in Quincy. Granite Avenue is under MassDOT jurisdiction from Milton Avenue in Boston to Squantum Street in Milton, and through the entirety of the study area. Granite Avenue is classified as an urban principal arterial north of the I-93 overpass and as an urban minor arterial south of the I-93 overpass. Granite Avenue northbound (NB) has a posted speed limit of 40 MPH for the majority of the study area, changes from 40 MPH to 30 MPH approaching the Neponset River, further reducing to 25 MPH once entering the City of Boston. Granite Avenue southbound (SB) has a posted speed limit of 30 MPH directly north of the study area over the Neponset River Bridge increasing to 45 MPH directly south of the study area. Within the study area, Granite Avenue provides two through lanes NB and SB and a paved shoulder in each direction, varying width between 2 and 10, with NB and SB traffic separated by a concrete median. The curb to curb width as measured in google earth is approximately 80 including the concrete median. There is a continuous asphalt sidewalk on the western side of the roadway that is approximately 6 wide as measured in google earth. There is no sidewalk along most of the eastern side of the roadway within the project limits; however, a sidewalk is provided north of the 2 Granite Avenue office building and south of Courtland Circle at the limits of the study area. There are no dedicated on- or off-road bicycle facilities, and bicyclists have been observed riding in the existing shoulder. There is no parking on either side of the roadway. Granite Avenue is a transit route servicing MBTA 215 buses as well as private shuttles servicing the MassDOT Park and Ride lot just south of the study area. The land use within the project limits along Granite Avenue includes a MassDOT maintenance yard, 2 Granite Avenue, and a residential cul-de-sac neighborhood off Courtland Circle. Just outside of the project limits the land use includes commercial businesses, the Presidents Golf Course, and the Neponset River Greenway Trail. Intersections Granite Avenue at Courtland Circle is a three-way intersection with three approaches: Granite Avenue NB, Granite Avenue SB, and Courtland Circle westbound. Courtland Circle is a dead-end, local roadway with one lane in each direction. Across Granite Avenue from Courtland Circle is the driveway for a MassDOT maintenance yard. Courtland Circle is stop-controlled and Granite Avenue is uncontrolled NB and SB. Asphalt sidewalks are present on both sides of Courtland Circle and both sides of Granite Avenue at the intersection. The eastern sidewalk along Granite Avenue ends just north of the intersection with Courtland Circle. There are no crosswalks or curb ramps at the intersection. There are no bicycle facilities provided through the intersection. On the nearside NB approach to the intersection is an existing MBTA bus stop that is being relocated to the intersection of Granite Avenue and Thistle Avenue south of the project limits. I-93 Interchange South is located between Courtland Circle and the I-93 overpass and includes the I-93 NB on-ramp from Granite Avenue NB and the I-93 NB off-ramp to Granite Avenue NB. Interchange South represents the southern half of the partial cloverleaf interchange located within the study area. All roadways are under MassDOT jurisdiction. Both interstate ramps are one-way, one-lane, limited access roadways, and are classified as urban minor arterials. The I-93 NB on-ramp has no posted speed limit. The I-93 NB off-ramp has a posted advisory speed limit of 35 MPH. The posted speed limits on Granite Avenue SB is 45 MPH within Interchange South. Asphalt sidewalks are only provided along the western side of Granite Avenue. The interstate ramps do not provide marked crosswalks or curb ramps. Bicycle facilities are not provided across the on or off-ramps. Page 4
I-93 Interchange North is located between the I-93 overpass and the 2 Granite Avenue driveway and includes three interstate ramps. Interchange North represents the northern half of the partial cloverleaf interchange located within the study area. For the NB direction, this includes Exit 11B to Granite Avenue NB. In the SB direction, this includes Granite Avenue SB to I-93 SB on-ramp and Exit 11A to Granite Avenue SB. All roadways in this segment are under MassDOT jurisdiction. All three interstate ramps are one-way, one lane, limited access roadways, and are classified as urban principal arterials. Both Exit 11A and 11B have a posted advisory speed limit of 25 MPH and the I-93 SB on-ramp has no posted speed limit. Exit 11B has a steep grade change and large super elevation. All off-ramps meet Granite Avenue in a way that motorists are parallel to the path of travel. The merge angle requires motorists to turn their heads more than 90 degrees, or rely on their mirrors to merge while looking for on-coming vehicles, pedestrians, and bicyclists. The off-ramps are yield-controlled while Granite Avenue is uncontrolled. Asphalt sidewalks are provided along the western side of Granite Avenue. Sidewalks on the east side of Granite Avenue begin north of 2 Granite Avenue. Marked crosswalks and curb ramps are not provided across the I-93 on- and off-ramps or the 2 Granite Avenue driveway. Dedicated bicycle facilities are not provided. Audit Observations and Potential Safety Enhancements Following an introduction to the RSA process and a summary of crash history data, the audit participants were asked to discuss safety concerns throughout the study area. Audit team members then walked the study area as a team and made additional observations while in the field. Based on field observations and discussion, the RSA team determined that all locations within the study area have the following general issues that affect safety: Speeding; Pedestrian Accommodations; Bicycling Accommodations; and Lighting. The following sections discuss observations and potential enhancements identified during the RSA. The report is organized by discussing observations and potential enhancements that pertain to all locations study-area wide, followed by intersection-specific observations and potential enhancements unique to each location. Note that current, applicable design standards referenced throughout the report include but are not limited to the MUTCD, Americans with Disabilities Act, MassDOT and the Town of Milton standards and specifications; in addition, consideration should be given to applicable local, state, and national guidelines. Several of the issues identified require further study and engineering judgment to determine the feasibility of implementing the improvements to address them. Page 5
Study Area-wide Observations Speeding The team noted that speeding on Granite Avenue is present at all times of day, and particularly during the off-peak periods. They noted that the roadway appears to have excess capacity throughout most of the study area, except for Granite Avenue NB during the morning peak hour. RSA members noted congestion and queues often back up from the I-93 NB on-ramp often to Squantum Road in the right lane. The wide, straight roadway with excess capacity was discussed as a contributing factor to speeding during off peak periods, especially at night. Team members also noted that it is difficult to exit driveways and side streets throughout the study area and along the length of the corridor due to the high speeds and multiple lanes. Based on the crash data, at least five crashes involved motorists entering or exiting driveways in the study area. RSA members noted that motorists often speed while merging onto Granite Avenue from the I-93 off-ramps. Given limited sight distances, speeding motorists may not have adequate time to react to slowed or stopped vehicles, causing rear-end crashes. As reflected in the crash data, there were ten rear-end crashes and five single vehicle crashes that may have been due to carrying excess speed around the curves at the off-ramps and merge areas. RSA members noted the study area lacks a consistent posted speed limit. The NB speed limit varies along the corridor from 40MPH through the southern portion of the study area, dropping to 30MPH at Exit 11B, and further dropping to 25MPH north the Neponset River Bridge, just outside of the study area. The SB speed limit begins at 30MPH at the northern portion of the study area and increases to 45MPH south of the intersection with Courtland Circle. The varying speed limits are difficult to enforce. Pedestrian Accommodations There were no pedestrian related crashes along the Granite Avenue corridor within the study area. There are missing sidewalks on the eastern side of Granite Avenue from north of Courtland circle to north of the 2 Granite Avenue driveway; however, there are narrow sidewalks provided directly under the I-93 overpass. The existing asphalt sidewalks along Granite Avenue are in poor condition and do not appear to meet accessibility requirements. They are approximately 5 to 6 wide and there are sign posts, utilities, and other obstructions in the pedestrian path of travel. There is no buffer zone on the sidewalk between pedestrians and high speed motor vehicle traffic. RSA members noted while in the field it was an uncomfortable, noisy, and generally felt unwelcoming for pedestrians to walk along the corridor. Throughout the study area there are no marked crosswalks or ADA accessible curb ramps provided across large Figure 2 Sidewalks end at Courtland Circle on the eastern side of Granite Avenue, and existing sidewalks are in poor condition. Page 6
driveways such as 2 Granite Avenue, intersections, and on- and off-ramps. Bicycling Accommodations There were no bike related crashes along the Granite Avenue corridor within the study area. There are no dedicated bicycle facilities present in the study area and bicyclists riding along the corridor typically use the existing, narrow paved shoulder. RSA team members noted that Granite Avenue is a desired bicycle route to access points north of Milton including the Neponset Greenway Trail and the City of Boston; however, due to high vehicle speeds and a lack of dedicated or separated bicycle infrastructure, it was reported that most bicyclists do not feel comfortable riding along Granite Avenue. Throughout the study area there are no Figure 3 - Cyclists are required to merge across high bicycle facilities across large driveways speed traffic on large on- and off-ramps without any such as 2 Granite Avenue, intersections, dedicated facilities, pavement markings, or signage. and on- and off-ramps. At existing bus stops there are conflicts between buses/bicyclists when buses pull to the shoulder to load and unload passengers, requiring bicyclist to wait behind the bus or merge into high speed vehicular traffic to pass the bus. Lighting Crash data provided by MPD indicated that 20% of the crashes in the area occurred in dark conditions, 11% occurred during dawn and dusk lighting conditions, and 70% of the crashes occurred in daylight. However, audit members noted that the existing lighting appears to be adequate for motor vehicles along the corridor. RSA team members noted there is insufficient lighting for pedestrians, particularly under the I-93 overpass. Potential Enhancements 1. Evaluate the multi-lane cross section of Granite Avenue and consider removing one travel lane per direction and provide dedicated turn lanes where necessary, such as for the I-93 NB on-ramp on Granite Avenue NB. With the additional space consider providing separated bicycle facilities to increase separation and safety for bicyclists, and to help reduce motor vehicle speeds. Also, consider providing a shared-use path along Granite Avenue on the west side of the roadway. 2. Provide a consistent speed limit on Granite Avenue throughout the study area and along the corridor in both directions that encourages safe travel for all users. In the short-term consider a modified speed zone application to post a consistent speed along the corridor. 3. In the long term, consider re-alignment and signalization of the two I-93 north and south interchanges on both sides of Granite Avenue. Consider aligning the on- and off-ramps to form a 90-degree signalized T-intersections with Granite Avenue to slow all motor vehicle turning Page 7
movements, improve sight lines, reduce conflict points, and shorten crossing distances for pedestrians and bicyclists. 4. Install continuous sidewalks where sidewalks are missing along the eastern side of Granite Avenue between Courtland Circle and 2 Granite Avenue, and repair existing sidewalks to meet accessibility requirements. 5. Consider widening sidewalks and providing a buffer zone between the roadway and the pedestrian walk zone to increase comfort, reduce noise, provide separation between pedestrians and high speed motor vehicle traffic, and increase visibility at crossings by increasing the crosswalk setback. 6. Provide accessible curb ramps at all crossings along Granite Avenue throughout the study area, including at I-93 on- and off-ramps. 7. Evaluate crosswalk locations and install high visibility ladder style pedestrian crosswalks at all intersections. Consider additional crossing measures, including rapid flash beacons, yield pavement markings, and pedestrian warning signage to alert users of potential conflicts at pedestrian crossings. 8. Consider bicycle conflict zone pavement markings, such as vehicle yield lines and green bicycle guidance markings, and signage to increase visibility of bicyclists at intersections and interchanges with I-93 throughout the study area. 9. If on-road bicycling facilities are provided, consider measures to minimize conflicts between buses and bicyclists at bus stops, such as routing bicyclists behind bus stops and conflict zone pavement markings. 10. Conduct a lighting evaluation and install pedestrian-scale lighting along the corridor to improve visibility at crosswalks and to increase personal safety underneath the I-93 overpass. Granite Avenue at Courtland Circle Observations Visibility due to Congestion The team noted that during morning and afternoon peak hours when 60% of crashes were reported there is congestion and queuing in the right lane on Granite Avenue NB approaching I-93 NB on-ramp. Congestion often blocks the Courtland Circle intersection. The vehicle queues in the right lane create visibility challenges for people trying to access or exit Courtland Circle and driveways on the east side of Granite Avenue along the corridor. The limited visibility can lead to angle crashes between vehicles turning off of Courtland Circle and vehicles travelling along Granite Avenue, such as crash #15 from the Crash Diagram. It can also lead to rear end crashes on Granite Avenue, as vehicles in the northbound left lane may have to brake suddenly to avoid vehicles turning off of Courtland Circle. Page 8
Conflict between U-Turns / Turning Movements and Through Movements Several team members noted and observed motorists making U-turns from Granite Avenue SB to access the I-93 NB on-ramp. During the morning peak hour, motorists often have been observed turning left from Granite Avenue SB onto Courtland Circle, turning around in Courtland Circle, and turning right to access I-93 NB because the U-turn movement is not possible due to congestion. The turning movements from Granite Avenue SB are the only access for motorists heading south on Granite Avenue to I-93 NB. In the morning peak hour, this movement also jumps a long queue of vehicles in the right lane of Granite Avenue NB waiting to access the I-93 NB on-ramp. There were four crashes were reported involving U-turn vehicles, and one involving left turning vehicle with the through traffic at Granite Avenue and Courtland Circle. Potential Enhancements 1. Add Do Not Block box pavement markings at Courtland Circle to help improve neighborhood access and increase visibility during peak periods. 2. As noted previously, in the long term consider realignment and signalization of the two I-93 north and south Figure 4 - Motorists often turn left into Courtland Circle before turning around and making a right to access I-93 NB. interchanges on both sides of Granite Avenue. Consider aligning the on- and off-ramps to form a 90-degree signalized T-intersections with Granite Avenue. When realigning and signalizing the onand off-ramps, consider providing a left turn lane and signal phase for Granite Avenue SB motorists onto I-93 NB on-ramp. This will eliminate the desire for U-turn movements at Courtland Circle. 3. The team discussed considering extending the Granite Avenue median south across Courtland Circle to prevent U-turn movements from Granite Avenue SB onto the I-93NB on-ramp. However, extending the median would restrict access to the Courtland Circle neighborhood and only relocate the location of the U-turn movement further south along Granite Avenue where the proposed median would end. Team members discussed not recommending extending the median. Page 9
Interchange South: Granite Avenue at I-93 NB on-ramp and I-93 NB off-ramp Observations Visibility due to Congestion As noted previously, there is congestion and queuing in the right lane on Granite Avenue NB approaching I-93 NB on-ramp. RSA members noted that congestion in the right lane can queue back to Squantum Road, and often vehicles will drive in the left lane and merge at the I-93 NB on-ramp two abreast to beat the queue. This creates queues in the left thru lane causing delay for motorists. The queuing can lead to rear-end crashes, two of which are reported along Granite Ave NB and on the I-93 NB entrance ramp where queuing is most often present. The team discussed that motorists may use Granite Avenue as a cut-through route for I-93NB when there is congestion. Motorists may exit I-93 NB at Exit 9 (Adams Street, Milton, N. Quincy) and Figure 5 Granite Avenue NB on-ramp queuing during peak hour congestion, as viewed from the Courtland Circle intersection looking south. continue north on Granite Avenue to the project area where they can re-enter the highway, contributing to increased congestion in the project area. Interchange Geometry Motorists exit the I-93 NB off-ramp onto Granite Avenue NB at high speeds and do not have adequate space to merge into traffic. There were nine reported rear end crashes, four resulting injuries, where speeds may have been a contributing factor. The I-93 Exit 11 off-ramp meets Granite Avenue at a shallow angle so that exiting motorists are approximately parallel to the path of approaching motorists. The merge angle requires motorists to turn their heads more than 90 degrees to merge while looking for on-coming vehicles, pedestrians, and bicyclists. The angle and high speeds of merging traffic reduce sight lines and the driver s cone of vision. Pedestrian Accommodations As noted previously, there are missing sidewalks on the eastern side of Granite Avenue NB from north of Courtland Circle to north of the 2 Granite Avenue driveway; however, there are narrow sidewalks provided directly under the I-93 overpass. There are no marked crosswalks or ADA accessible curb ramps provided across the I-93 NB on- and off-ramps. Bicycling Accommodations There are no dedicated bicycle facilities across the on- and off- ramps where there are high speeds and conflict point between merging motorists and thru bicyclists. Page 10
Potential Enhancements 1. Consider providing one right turn only lane onto I-93 NB and one through lane for NB traffic on Granite Avenue toward the City of Boston line. This will reduce the use of the left lane as a queue jump, and discourage motorists from attempting to merge into the right lane immediately prior to the I-93 NB on-ramp. Provide appropriate pavement markings and signage per the latest edition of the MUTCD. 2. Consider increasing police enforcement to discourage late merging and queue jumping, particularly for the morning peak hour on Granite Avenue NB onto I-93 NB on-ramp to reduce side swipe crashes and congestion in the thru lane. 3. Consider providing sidewalks and installing high visibility ladder style pedestrian crosswalks and accessible curb ramps across I-93 NB on- and off-ramps. I-93 NB on-ramp has a limited sight distance that may be additionally limited by a tree on the east side of the roadway in the summer months. Consider additional crossing measures, including adequate pedestrian lighting, rapid flash beacons, yield pavement markings, and warning signage to alert users of potential conflicts at pedestrian crossings. 4. Install continuous sidewalks where sidewalks are missing along the eastern side of Granite Avenue between Courtland Circle and 2 Granite Avenue, and repair existing sidewalks to meet accessibility requirements. 5. Consider bicycle conflict zone pavement markings and signage to increase visibility of bicyclists across I-93 NB on- and off-ramps. 6. In the long term, consider re-alignment and signalization of the two I-93 north and south on-ramps to form a 90-degree signalized T-intersection with Granite Avenue to slow all motor vehicle turning movements, improve sight lines, reduce conflict points, and shorten crossing distances for pedestrians and bicyclists. This will also eliminate the need for a Granite Avenue SB U-turn to access I-93 NB. 7. Evaluate the feasibility of a roundabout as a replacement for the Courtland Circle intersection. This will eliminate the Granite Avenue SB to I-93 NB U-turn movement while maintaining access to Courtland Circle and the MassDOT maintenance yard. Right-of-way availability will need to be evaluated in order to assess the feasibility of a roundabout. 8. Evaluate the multi-lane cross section of Granite Avenue and consider removing one travel lane per direction and provide dedicated turn lanes where necessary, such as for the I-93 NB on-ramp on Granite Avenue NB. Page 11
Interchange North: Granite Avenue NB at I-93 SB off-ramp and 2 Granite Avenue Driveway; Granite Avenue SB at I-93 SB on-ramp and I-93 SB off-ramp Observations U-turns / Turning Movements The team noted that there is a desire to make a U-turn from Granite Avenue NB onto Granite Avenue SB. Particularly during the PM peak hours, there is often congestion on I-93 SB. RSA members noted that motorists will often take the I-93 SB exit 11B toward Granite Avenue NB to avoid congestion and reduce delay, merge abruptly across two lanes of northbound traffic to make an uncontrolled U-turn to continue onto Granite Avenue SB. There were six Figure 6 Motorists often perform uncontrolled U-turns from Granite Avenue NB to Granite Avenue SB. reported U-turn crashes from Granite Avenue NB at this location including one fatal motorcycle crash with a U-turning truck as well as two turning movement crashes and one sideswipe with vehicles merging from the I-93 SB off-ramp and attempting to make a U-turn. RSA members noted that the Granite Avenue NB to Granite Avenue SB U-turn is also utilized by local traffic potentially because of the difficulty of turning left at uncontrolled driveways and side streets along the corridor; motorists exiting local residences and businesses along the east side of Granite Avenue have difficulty turning left, and have been observed turning right to then perform a U-turn to then proceed SB on Granite Avenue. It was also noted that the Milton Fire Department, Milton DPW, and MassDOT DPW require access for fire trucks and large maintenance trucks to perform the Granite Avenue NB to Granite Avenue SB U-turn to access I-93 SB. RSA members noted that large trucks currently need to swing into the right NB lane to have enough space to complete the U-turn. Interchange Geometry RSA members noted that turning left out of the 2 Granite Avenue driveway is challenging due to the need to cross two lanes of oncoming NB traffic as well as the I-93 NB of-ramp traffic, as well as merge into two lanes of Granite Avenue SB traffic. This challenge may contribute to courtesy crashes at this location. A courtesy crash is when a driver yields the courtesy to a vehicle turning into or out of a driveway to pass through, resulting in a collision with a vehicle traveling in an adjacent lane. There are two angle crashes involving left turning vehicles colliding with the NB and SB through vehicles at the 2 Granite Avenue driveway. The 2 Granite Avenue driveway is wide and has large radii, allowing motorists to enter and exit at high speeds. The width of the driveway increases pedestrian exposure. Motorists entering the 2 Granite Avenue driveway conflict with motorists merging from the I-93SB off-ramp onto Granite Avenue NB. Motorists exiting the interstate must check left and behind themselves in order to merge with traffic moving northbound along Granite Avenue. At the same time, motorists from Granite Avenue may be attempting to merge right across the Page 12
exit ramp to access 2 Granite Avenue. This weaving of traffic presents a potential safety risk, as motorists accessing 2 Granite Avenue are slowing as they cross the paths of motorists merging onto Granite Avenue and attempting to match the prevailing speed of traffic on the roadway. Motorists exit the I-93 SB off-ramp onto Granite Avenue NB at high speeds and have inadequate space due to the short merge area and narrow shoulder to merge into traffic. The I-93 SB off-ramps meet Granite Avenue so motorists are parallel to the path of travel. The merge angle requires motorists to turn their heads more than 90 degrees, or rely on their mirrors to merge while looking for on-coming vehicles, pedestrians, and bicyclists. The angle and high speeds of merging traffic reduce sight lines and the driver s cone of vision. The I-93 SB off-ramp lacks extension line markings to delineate where it meets and merges with the right lane of Granite Avenue NB. Pedestrian Accommodations There are no marked crosswalks or ADA accessible curb ramps provided across the I-93 SB off-ramp, 2 Granite Avenue driveway, or I-93 SB on- and off-ramps. Along Granite Avenue NB there are no existing sidewalks on the eastern side of the roadway from the I-93 overpass to north of 2 Granite Avenue. Along Granite Avenue SB there are existing asphalt sidewalks in poor condition and do not appear to meet accessibility requirements. They are approximately 5 to 6 wide and there are sign posts, utilities, and other obstructions in the pedestrian path of travel. There is no buffer zone on the existing sidewalk between pedestrians and high speed motor vehicle traffic. RSA members noted while in the field it was an uncomfortable, noisy, and generally felt unwelcoming for pedestrians to walk along the corridor. There is no signage, crosswalks, or curb ramps provided to alert pedestrian where to cross Granite Avenue to continue on the existing sidewalks. There is pedestrian access to wetlands behind 2 Granite Avenue, however there are no wayfinding signs or crossings across Granite Avenue to access the trails within the vicinity of 2 Granite Avenue. Bicycling Accommodations There are no dedicated bicycle facilities across the on- and off- ramps where there are high speeds and conflict point between merging motorists and thru bicyclists. Potential Enhancements 1. In the short term consider installing pavement markings or flexible delineator posts to provide a designated and adequate merge space for the I-93SB motorists onto Granite Avenue NB. Consider extending the merge area to eliminate the ability for motorists exiting I-93 SB off-ramp to make abrupt lane changes across two lanes of Granite Avenue NB traffic to perform a U-turn onto Granite Avenue SB. 2. Consider providing yield markings, to increase the attention of yield control, on Exit 11B as it merges with Granite Avenue NB. Currently only a yield sign is provided. 3. In the long term, consider re-alignment and signalization of the I-93 SB on- and off-ramps on the west side of Granite Avenue to form a 90-degree signalized T-intersection with Granite Avenue Page 13
SB. Forming a 90-degree angle will slow all motor vehicle turning movements, improve sight lines, reduce conflict points, and shorten crossing distances for pedestrians and bicyclists. 4. Evaluate options to address the desire line for motorists to make U-turns from Granite Avenue NB onto Granite Avenue SB north at the existing gap in the median prior to the 2 Granite Avenue driveway: a. Consider closing the existing gap in the median and restricting U-turns for passenger vehicles. Consider treatments to permit emergency and maintenance vehicles to still make the U-turn via mountable curbs and paving treatments. b. Consider providing a dedicated U-turn lane and one thru lane for Granite Avenue NB via pavement markings and signage. 5. Consider reducing the curb radii on the driveway for 2 Granite Avenue to slow traffic entering and exiting the parking lot. 6. In the short term, add signage to direct pedestrians to cross the roadway and indicate the lack of continuous sidewalk along the eastern side of Granite Avenue at the nearest crossing to the north and south. Direct pedestrians to use the western sidewalk if they are continuing south of the I-93 interchange. 7. Install continuous sidewalks where sidewalks are missing, and repair existing sidewalks to meet accessibility requirements. 8. Consider widening sidewalks and providing a buffer zone between the roadway and the pedestrian walk zone to increase comfort, reduce noise, provide separation between pedestrians and high speed motor vehicle traffic, and increase visibility at crossings by increasing the crosswalk setback. 9. When sidewalks are constructed, install high visibility ladder style pedestrian crosswalks and accessible curb ramps across I-93 SB on- and off-ramps. The location of the crosswalk needs to maximize pedestrian visibility to oncoming vehicles, and must be before the location where vehicles begin to accelerate for the on-ramp. I-93 SB on-ramp has a limited sight distance that may be additionally limited by a tree on the east side of the roadway in the summer months. Consider additional crossing measures, including adequate pedestrian lighting, rapid flash beacons, yield pavement markings, and warning signage to alert users of potential conflicts at pedestrian crossings. 10. Consider bicycle conflict zone pavement markings and signage to increase visibility of bicyclists across the I-93 SB on- and off-ramps and the 2 Granite Avenue driveway. Page 14
Summary of Road Safety Audit Based on observations and discussions, the RSA team identified the issues and potential enhancements that could improve safety along Granite Avenue in Milton, MA. The timeframe and costs are categorized below in Table 2. Table 2: Estimated Time Frame and Costs Breakdown Time Frame Costs Short-Term <1 Year Low <$10,000 Mid-Term 1-3 Years Medium $10,001-$50,000 Long-Term >3 Years High >$50,000 Table 3 lists each safety issue and the corresponding potential safety enhancements that were discussed at the audit and within the previous section. The table includes the safety benefit, estimated timeframe for completion, estimated construction cost, and the responsible agency for each observed safety issue and potential safety enhancement. Safety payoff estimates are subjective and may be based on the relative percent of crashes that may be reduced by the enhancement based on known and documented crash reduction factors, if available, or estimated crash reduction based on a stated source. Page 15
Road Safety Audit Granite Avenue at I-93 Ramps, Milton, MA Table 3: Potential Safety Enhancement Summary Safety Issue Potential Safety Enhancement Safety Payoff Time Frame Cost Responsible Agency Speeding Speeding Speeding / Pedestrian / Bicycle Accommodations Pedestrian Accommodations Study Area-wide Evaluate the multi-lane cross section of Granite Avenue and consider removing one travel lane per direction and provide dedicated turn lanes where necessary. Consider separated bicycle facilities and/or a shared-use path along Granite Avenue on the west side of the roadway. Provide a consistent speed limit on Granite Avenue throughout the study area and along the corridor in both directions that encourages safe travel for all users. Consider re-alignment and signalization of the I-93 north and south interchanges on both sides of Granite Avenue. Consider aligning the on- and off-ramps to form 90-degree signalized T-intersections with Granite Avenue. Install continuous sidewalks where sidewalks are missing, and repair existing sidewalks to meet accessibility requirements. High Mid-term High MassDOT Mid Short-term Low MassDOT / Town of Milton High Long-term High MassDOT High Long-term High MassDOT Pedestrian Accommodations Consider widening sidewalks and providing a buffer zone between the roadway and the pedestrian walk zone. High Long-term High MassDOT Pedestrian Accommodations Pedestrian Accommodations Bicycling Accommodations Bicycling Accommodations Visibility Provide accessible curb ramps at all crossings along Granite Avenue throughout the study area. Evaluate crosswalk locations and install high visibility ladder style pedestrian crosswalks at all intersections. Consider additional crossing measures to alert users of potential conflicts at pedestrian crossings. High Mid-term Medium MassDOT High Mid-term Low MassDOT Consider bicycle conflict zone pavement markings and signage. Mid Short-term Low MassDOT If on-road bicycling facilities are provided, consider measures to minimize conflicts between buses and bicyclists at bus stops such as routing bicyclists behind bus stops and conflict zone pavement markings. Conduct a lighting evaluation and install pedestrian-scale lighting along the corridor. Mid Mid-term Low MassDOT High Long-term High MassDOT Page 16
Road Safety Audit Granite Avenue at I-93 Ramps, Milton, MA Safety Issue Potential Safety Enhancement Safety Payoff Time Frame Cost Responsible Agency Visibility due to Congestion Conflict Between Turning Movements & Through Traffic Conflict Between Turning Movements & Through Traffic Visibility due to Congestion Pedestrian Accommodations Pedestrian Accommodations Bicycling Accommodations Interchange Geometry Interchange Geometry Interchange Geometry Granite Avenue at Courtland Circle Add Do Not Block box pavement markings at Courtland Circle. Mid Short-term Low MassDOT Consider re-alignment and signalization of the I-93 north and south interchanges on both sides of Granite Avenue. Consider providing a left turn lane and signal phase for Granite Avenue SB motorists onto I-93 NB on-ramp. Interchange South: Granite Avenue at I-93 NB on-ramp and I-93 NB off-ramp Consider providing one right turn only lane onto I-93 NB and one through lane for NB traffic toward the City of Boston line. Consider increasing police enforcement to discourage late merging and queue jumping, particularly for the morning peak hour on Granite Avenue NB onto I-93 NB on-ramp. Consider providing sidewalks and installing high visibility ladder style pedestrian crosswalks and accessible curb ramps across I-93 NB onand off-ramps. Consider additional crossing measures, including rapid flash beacons, yield pavement markings, and warning signage to alert users of potential conflicts at pedestrian crossings. Install continuous sidewalks where sidewalks are missing, and repair existing sidewalks to meet accessibility requirements. High Long-term High MassDOT High Long-term High MassDOT Low Short-term Medium MassDOT / Milton Police Department High Long-term High MassDOT High Long-term High MassDOT Consider bicycle conflict zone pavement markings and signage. Mid Short-term Low MassDOT Consider re-alignment and signalization of the I-93 north and south interchanges on both sides of Granite Avenue. Consider aligning the on- and off-ramps to form 90-degree signalized T-intersections with Granite Avenue. Evaluate the feasibility of a roundabout at the Courtland Circle intersection. A roundabout could also pose right-of-way issues further study would be required before pursuing this alternative. Evaluate the multi-lane cross section of Granite Avenue and consider removing one travel lane per direction and provide dedicated turn lanes where necessary, such as for the I-93 NB on-ramp on Granite Avenue NB. High Long-term High MassDOT High Long-term High MassDOT High Long-term High MassDOT Page 17
Road Safety Audit Granite Avenue at I-93 Ramps, Milton, MA Safety Issue Potential Safety Enhancement Safety Payoff Time Frame Cost Responsible Agency Interchange North: Granite Avenue NB at I-93 SB off-ramp and 2 Granite Avenue Driveway; Granite Avenue SB at I-93 SB on-ramp and I-93 SB off-ramp Interchange Geometry Interchange Geometry Interchange Geometry Conflict Between Turning Movements & Through Traffic Conflict Between Turning Movements & Through Traffic Pedestrian Accommodations Pedestrian Accommodations Consider installing pavement markings and flexible delineator posts to provide a designated and adequate merge space for the I-93SB motorists onto Granite Avenue NB. Consider extending the merge area to eliminate the ability for motorists exiting I-93 SB off-ramp to make abrupt lane changes across two lanes of Granite Avenue NB traffic to perform a U-turn onto Granite Avenue SB. Consider providing yield markings on Exit 11B as it merges with Granite Avenue NB. Consider re-alignment and signalization of the I-93 north and south interchanges on both sides of Granite Avenue. Consider aligning the on- and off-ramps to form 90-degree signalized T-intersections with Granite Avenue. Evaluate options to address the desire line for motorists to make U- turns from Granite Avenue NB onto Granite Avenue SB north at the existing gap in the median prior to the 2 Granite Avenue driveway. Consider closing the existing gap in the median and restricting U-turns for passenger vehicles. Consider treatments to permit emergency and maintenance vehicles to make the U-turn via mountable curbs and paving treatments. Evaluate options to address the desire line for motorists to make U- turns from Granite Avenue NB onto Granite Avenue SB north at the existing gap in the median prior to the 2 Granite Avenue driveway. Consider providing a dedicated U-turn lane and one thru lane for Granite Avenue NB via pavement markings and signage. Consider reducing the curb radii on the driveway for 2 Granite Avenue to slow traffic entering and exiting the parking lot. Add signage to direct pedestrians to cross the roadway and indicate the lack of continuous sidewalk along the eastern side of Granite Avenue at the nearest crossing to the north and south. High Mid-term Low MassDOT Mid Short-term Low MassDOT High Long-term High MassDOT High Short-term Low MassDOT High Short-term Mid MassDOT High Mid-term Mid MassDOT Low Short-term Low MassDOT Page 18
Road Safety Audit Granite Avenue at I-93 Ramps, Milton, MA Safety Issue Potential Safety Enhancement Safety Payoff Time Frame Cost Responsible Agency Pedestrian Accommodations Pedestrian Accommodations Pedestrian Accommodations Bicycling Accommodations Install continuous sidewalks where sidewalks are missing, and repair existing sidewalks to meet accessibility requirements. Consider widening sidewalks and providing a buffer zone between the roadway and the pedestrian walk zone. When sidewalks are constructed, install high visibility ladder style pedestrian crosswalks and accessible curb ramps across I-93 SB onand off-ramps. Consider additional crossing measures, including adequate pedestrian lighting, rapid flash beacons, yield pavement markings, and warning signage to alert users of potential conflicts at pedestrian crossings. High Long-term High MassDOT High Long-term High MassDOT High Short-term Low MassDOT Consider bicycle conflict zone pavement markings and signage. Mid Short-term Low MassDOT Page 19
Appendix A. RSA Meeting Agenda
Road Safety Audit Milton, MA Granite Avenue, between Neponset Bridge and Courtland Circle Meeting Location: To be determined April 5, 2017 09:00 AM Noon Type of meeting: Attendees: Please bring: High crash location Road Safety Audit Invited participants to comprise a multidisciplinary team Thoughts and enthusiasm!! 09:00 AM Welcome and Introductions 09:15 AM Discussion of Safety Issues 10:00 AM Site Visit Crash history, speed regulations, recent and existing projects all provided in advance Existing geometries and conditions Drive to Granite Avenue As a group, identify areas for improvement 11:00 AM Discussion of Potential Improvements Discuss observations and finalize safety issue areas Discuss potential improvements and finalize recommendations Noon Adjourn for the Day but the RSA has not ended Instructions for Participants: Before attending the RSA on April 5, participants are encouraged to drive/walk through the intersection and complete/consider elements on the RSA Prompt List with a focus on safety. All participants will be actively involved in the process throughout. Participants are encouraged to come with thoughts and ideas, but are reminded that the synergy that develops and respect for others opinions are key elements to the success of the overall RSA process. After the RSA meeting, participants will be asked to comment and respond to the document materials to assure it is reflective of the RSA completed by the multidisciplinary team.
Appendix B. RSA Audit Team Contact List
Audit Team Members Date: April 5, 2017 Location: Granite Avenue at I-93, Milton, MA Audit Team Agency/Affiliation Members Email Address Phone Number Mark Alba Milton Police Department malba@mpdmilton.org 617.898.4814 Michelle Deng MassDOT Traffic Safety michelle.deng@dot.state.ma.us 857.368.9637 Elsa Chan MassDOT Traffic Safety elsa.chan@dot.state.ma.us 857.368.9648 William Clark Milton Planning Department wclark@townofmilton.org 617.898.4847 Chris Trudel Milton Department of Public Works ctrudel@townofmilton.org 617.898.4870 John Thompson Milton Department of Public Works jthompson@townofmilton.org 617.898.4869 Lee Toma Milton Bike Committee lee.toma@bikemilton.org 617.251.6528 Chen-Yuan Wang CTPS/ Boston Region MPO cwang@stps.org 857.702.3698 Rob Ballasty MassDOT Traffic Operations robert.ballasty@dot.state.ma.us 857.368.6312 Jack Grant Milton Fire Department jgrant@townofmilton.org 617.898.4904 Geri Vatan MassDOT D6 geraldine.vatan@dot.state.ma.us 857.368.6115 Courtney Dwyer MassDOT D6 courtney.dwyer@dot.state.ma.us 857.368.6165 Jeff Parenti Nitsch Engineering jparenti@nitscheng.com 857.206.8695 Jessica Mortell Toole Design Group jmortell@tooledesign.com 617.619.9910 Preston Buehrer Toole Design Group pbuehrer@tooledesign.com 617.619.9910
Appendix C. Detailed Crash Data