Frequently Asked Questions

When a speeding concern is brought to the Traffic Safety Group’s attention, staff first review available speed data and crash history for the roadway. If the 85th percentile speed indicates that drivers are traveling above the speed limit, the Traffic Safety Group may deploy a temporary speed feedback trailer. These trailers are effective at increasing driver awareness in residential neighborhoods and reducing speeding, particularly when rotated between locations.

If speeding concerns persist, targeted police enforcement may be conducted as resources allow. The Traffic Safety Group will also review roadway characteristics and consider low cost measures such as pavement markings and appropriate advisory signage for statutory speed limit roadways. If speeds remain high after these measures are implemented, more substantial infrastructure changes may be considered. Larger roadway modifications require further evaluation and must be incorporated into the Town’s capital plan for funding.

It is important to note that most roadways in Wellesley are governed by a statutory speed limit of 30 miles per hour, which can feel fast on residential streets, particularly for larger vehicles or vehicles equipped with snow tires.

Some roads have a regulatory speed limit indicated by posted white speed limit signs, while others are governed by a statutory speed limit. The majority of roadways in Wellesley fall under the statutory speed limit category.

To change a posted speed limit, a speed study must be conducted and submitted to the Massachusetts Department of Transportation (MassDOT). Speed limits are typically set based on the 85th percentile speed, defined as the speed at or below which 85% of drivers are traveling. In some cases, this methodology can result in a higher posted speed limit on roads where speeding is already a concern.

Statutory speed limits are controlled by the legislature.  Under Massachusetts law, regulatory speed limit signs are not permitted on roadways governed by statutory speed limits. Instead, only advisory signage, such as “Thickly Settled” or “Business District” signs, may be used to inform drivers of the applicable statutory conditions.

Lowering the posted speed limit alone does not usually change driver behavior. A more effective approach is to change the roadway itself by incorporating permanent traffic calming features that encourage slower speeds, such as curb extensions or narrowed travel lanes.

Dynamic Speed Display Signs also referred to as radar speed signs or speed feedback signs are signs that measure vehicle speeds, typically using radar, and report the speed back to drivers.

Speed feedback signs can be an effective tool for reducing speeds when first installed. However, their effectiveness often diminishes over time as drivers become accustomed to the device. For this reason, the Traffic Safety Group generally recommends the use of speed feedback trailers or temporary pole mounted speed feedback signs on narrower roadways instead. These mobile speed feedback units can be rotated to different locations throughout town, which helps maintain driver awareness and serve as an effective traffic calming measure.

On high volume roads, permanent signs may be considered in limited circumstances, at:

• Locations with a documented history of speeding, higher crash rates, or where speed limits are frequently disregarded.
• School Zones 
• Gateway locations where there is a change in in the surrounding land use, or where pedestrian activity or complex intersections may not be readily expected by drivers.

Stop signs are used to control intersections and establish right of way. They are not intended to be used as a speed control measure. The Manual on Uniform Traffic Control Devices (MUTCD) requires that specific criteria be met before a stop sign is installed. When evaluating a request, the Traffic Safety Group considers factors such as traffic volumes, approach speeds, sight distance, crash history, and intersection geometry to determine whether a stop or yield sign is warranted.

Because stop and yield signs are regulatory traffic controls, they require approval by the Select Board, acting as the Road Commissioners for town-owned roadways. If the Traffic Safety Group determines that a stop or yield sign is appropriate, a recommendation will be made to the Select Board to amend the Town’s Traffic Regulations to include the new sign.  The Select Board, at a public meeting, will discuss and vote on the matter.

The Traffic Safety Group does not recommend the installation of convex mirrors for use on public streets.

Convex mirrors are commonly used to improve visibility for pedestrians and vehicles in a variety of areas including warehouses, driveways and parking areas. You may see convex mirrors installed in a few places in town.  Currently, there appears to be no research or documentation from any US state or federal government agencies including the Manual for Uniformed Traffic Control Devices (MUTCD) regarding the use of convex mirrors within the public right-of-way.  While convex mirrors may be appropriate for some low speed applications, they are not appropriate for use in public ways because:  

• Mirrors do not function well at night, as they can be difficult to see and lights from vehicles reflect in different directions.
• Mirrors do not work in poor weather conditions, including rain, snow and ice events.
• Mirrors can be knocked out of alignment, due to high winds and other severe weather conditions. 
• Mirrors distort the image, speed and distance of the oncoming traffic and are difficult to use. 

Rectangular Rapid Flashing Beacons, commonly referred to as RRFBs, are pedestrian warning devices that display flashing yellow lights when activated by a pedestrian, either through a push button or motion detection. RRFBs are intended to alert drivers to the presence of pedestrians and reinforce the requirement to yield. These devices are typically used at midblock crossings and in areas such as school zones or near parks.

It is important to note that RRFBs display yellow warning lights, not a red signal. Pedestrians, particularly children, should be reminded that RRFBs do not function like a traffic signal. Pedestrians should continue to make eye contact with approaching drivers and cross only when it is safe to do so.

When evaluating potential RRFB locations, the Traffic Safety Group considers factors such as crash history involving pedestrian or bicyclist conflicts, pedestrian volumes, traffic volumes and speeds, observed driver behavior, available gaps in traffic, and proximity to nearby crosswalks or existing RRFBs.

RRFB installations are reserved for locations with demonstrated pedestrian safety concerns and higher pedestrian activity. Overuse of RRFB treatments may reduce their effectiveness. In some cases, RRFB installations may require additional engineering analysis and may need to be incorporated into the Town’s capital plan for funding.

The Town does not generally support the use of speed humps or speed bumps on public roadways. While these treatments can reduce vehicle speeds, experience in other communities has shown that they may also lead to unintended consequences, including erratic driver behavior such as accelerating between them.

Speed humps can also create increased noise impacts and can be frustrating for immediate abutters who must drive over them repeatedly as part of daily travel. In addition, speed humps present significant roadway maintenance challenges, particularly in New England. Snow plowing, ice control, and pavement maintenance are more difficult and costly in areas where speed humps are installed, and these features can be damaged during winter operations.

Due to these operational, maintenance, and safety concerns, speed humps are typically not considered a viable long term solution. Other traffic calming measures that alter driver behavior and roadway design are often more effective and better suited for addressing speeding concerns.

 Warning signs can be effective when used sparingly and only to alert motorists to uncommon hazards that are not readily apparent. Because children live on nearly every residential street, this condition is not considered an uncommon hazard.

The Manual on Uniform Traffic Control Devices (MUTCD) does not include these types of signs, as there is no evidence that they influence driver behavior or provide traffic calming benefits. The Traffic Safety Group is mindful of sign fatigue and seeks to avoid overuse of nonstandard signs that could reduce the effectiveness of critical signage, such as crosswalk warnings.

Because the public has a right to travel on municipal roadways, these types of signs are unenforceable by the Police Department and may shift traffic to other neighborhoods. While cut-through traffic can result from temporary events such as crashes or short-term detours, longer term or large-scale construction related detours are reviewed by the Traffic Safety Group to evaluate traffic impacts and address effects on surrounding streets. 

These types of regulatory signs apply to all drivers including local residents and school buses. Periodic enforcement is essential to ensure continued compliance with the restriction. This option has major impacts on a neighborhood and its residents as it eliminates connectivity to surrounding roadways. It is also likely to shift traffic to adjacent neighborhoods. It should only be considered under certain circumstances, or when other options have been exhausted.   The Traffic Safety Group would conduct an engineering study to understand the root cause and to first identify other less invasive measures.  A measure such as this would require consultation and general consensus of the neighborhood as well as town departments.