Illegal and unreasonable speed limits in Massachusetts

(Jump to: numbered routes, Route 2, Route 2A, Route 3, Route 6, Route 7, Route 8, Route 9, Route 20, Route 146, Turnpike, MDC (DCR), Belchertown, Bellingham, Belmont, Blackstone, Boston, Brockton, Clinton, Dalton, Dover, East Brookfield, Georgetown, Holden, Hopkinton, Hubbardston, Lexington, Lincoln, Lynn, Medford, Melrose, Milford, Millis, Milton, Mount Washington, Newton, North Reading, Northbridge, Oxford, Pepperell, Petersham, Phillipston, Randolph, Royalston, Shirley, Shirley, Swampscott, Templeton, Tewksbury, Ware, Wareham, Watertown, West Springfield, Westborough, Westford, Worcester.)

Introduction

This page lists improper speed limits in Massachusetts, including speed limits which are illegal because they are posted in direct violation of state statute, and others which are unreasonable (and possibly illegal) because they are not justified by road and traffic conditions.

"Illegal" on this page is defined to mean a speed limit for which state approval is required according to Chapter 90, Section 18 of the General Laws, which was posted without such approval. There are two common types of illegal speed limits: 30 mile per hour postings in areas which the town government has decreed residential, and postings for which the speed limit was arbitrarily decided by the town.

It is not allowed in Massachusetts to post a sign showing the statutory speed limit; if a sign is to be posted the specific speed limit must be approved by the state. In the words of MassHighway:

All posted regulatory speed limit signs must adhere to this approval process. If a speed limit is posted without this procedure, it is in violation of Chapter 90, Section 18, and is therefore considered illegal and unenforceable.

Other speed limits are considered unreasonable; they were approved by MassHighway (if required) but are not justified by an engineering study. This could mean that no study was done, a study was done but was overruled, or a study was done but the engineers did not follow engineering standards, or a proper study was done but the passage of time has rendered the study obsolete. This may make them illegal. Note that the California speed trap law strictly requiring engineering studies at five year intervals does not apply to Massachusetts.

Speed limits must be justified by a written study by a professional engineer. The statutory requirement in Massachusetts is that any posted speed limit must be determined to be "in the public interest" by the state Highway Department and the Registry of Motor Vehicles. While this is quite vague, a separate statute requires that traffic control devices comply with the Manual On Uniform Traffic Control Devices (MUTCD). Federal law imposes a similar requirement. MUTCD section 2B.13 requires that an engineering study precede the posting of a speed limit and lists factors that may or must be considered in choosing a speed limit.

The legal and engineering process for setting a speed limit in Massachusetts is described by the speed zoning manual available from MassHighway on this page. A speed limit should be near the 85th percentile speed of free-flowing traffic. That is the speed which 85% of vehicles are at or below, and is typically about five miles per hour above the average speed. Under Massachusetts policy exceptional circumstances might justify a speed limit seven miles per hour below the 85th percentile.

Where known, 85th percentile speeds are listed for each road which is described as having an illegal or unreasonable speed limit. When speeds are displayed in tabular form, "50th" means the median speed, "85th" means the 85th percentile speed, and "%" means the percentage of drivers voluntarily obeying the speed limit. Speeds are measured except where explicitly called estimated.

When a speed limit is said to have been lowered due to the NMSL, that means it was reduced to 50 in November, 1973 in response to President Nixon's energy emergency declaration and raised to to 55 in January, 1974 when the National Maximum Speed Limit law dictated that limit instead.

MassHighway does not post speed limits over 65. Every existing 65 mile per hour zone is posted well below the 85th percentile speed, which is between 70 and 80 on almost all rural freeways. These limits are not listed individually.

Lists

Numbered Routes

Route 1

In 1999 a uniform speed limit of 50 miles per hour was imposed on Route 1 from Malden to Danvers, replacing speed limits that ranged from 45 to 55. The uniform limit is well below the 85th percentile speed. A 60 mile per hour limit more consistent with engineering standards was rejected because it "would not be acceptable to local officials." Some other parts of Route 1 have limits only slightly below the 85th percentile.

Route 2

The speed limit on Route 2 was adjusted after an engineering review in the late 1960s. In most places the speed limit has been reduced since then.

Arlington, Belmont, and Lexington

Route 2 east of Route 128 was rebuilt as freeway around 1970. The speed limit was initially posted at 60 based on an engineering study, though the study showed that 65 might be a more appropriate limit. The limit was lowered due to the NMSL and never restored. The current 85th percentile speed is between 70 and 75.

Lincoln, Concord, and Acton

The speed limit through Lincoln and Concord used to be mostly 50 and 55, and the speed limit west of the rotary was 60. Due to political pressure in response to head-on collisions the limit was reduced to 45 in 1973 without an engineering study. A followup study in the late 1970s showed that travel speeds had not decreased after the speed limit was reduced. Over the next few decades a median barrier was installed on almost all of this section of highway but restoring the speed limit was too politically risky. The current 85th percentile speed is between 60 and 65 through Lincoln and Concord, and higher west of the Concord Rotary.

Acton to Leominster

The limited access highway from Acton to Leominster was posted 55 when it opened in 1953 and raised to 60 in 1969. The limit was lowered due to the NMSL and never restored. The current 85th percentile speed is between 70 and 75.

Westminster to Philipston

As the Route 2 freeway west of Fitchburg was completed in the late 1960s and early 1970s it was posted 65 except for a short 60 zone in Gardner. The limit was lowered due to the NMSL and never restored. The current 85th percentile speed is between 70 and 75.

Philipston to Orange

The Athol bypass was posted 55 when it opened in the late 1950s. An engineering study in 1969 recommended a 60 mile per hour speed limit but the limit remained 55. The current 85th percentile speed is close to 65.

Erving

The speed limit in part of Erving was reduced from 50 to 40 in the late 1970s despite an engineering study finding the 85th percentile speed was over 50. The estimated 85th percentile speed in the 55 zone is 65.

Greenfield

The speed limit on the divided Route 2 connector was lowered from 60 due to the NMSL and never restored.

Charlemont to Florida

The speed limit between Charlemont and Florida is mostly based on curve speeds, which are now required to be advisory rather than regulatory speeds.

Route 2A

The speed limit on Route 2A through Lexington and Lincoln has been lowered or kept low by political pressure. The fastest vehicle recorded in the speed study near Tufts Road was a MassHighway truck doing 20 over the speed limit.

Route 3

The speed limit on the limited access highway sections of Route 3, from Bourne to Quincy and Burlington to New Hampshire, was set at 60 based on engineering studies in the 1960s and lowered due to the NMSL. The speed limit on Route 3 north has not been restored even though the design speed of the new highway is 70 and the 85th percentile speed is 77. The speed limit on Route 3 south was raised to 60 as a political favor to (former) House Minority Leader Fran Marini; he had asked for 65 and the engineering study found 85th percentile speeds from 65 to 71.

Route 6

Bourne to Dennis

The divided four lane section of Route 6 on Cape Cod was posted 60 and reduced due to the NMSL. The current 85th percentile speed is between 70 and 75.

Dennis to Orleans

The two lane, limited access section of Route 6 was reduced from 55 to 50 in 1974. Simultaneously the speed limit was reduced on the limited access two lane section of Route 44. These reductions appear to have been based on a policy decision to treat two lane roads differently rather than an engineering study.

Eastham to Truro

In 1997 the speed limit from Truro to Eastham was reduced from 50 and 55 to 45 under pressure from local politicians. This reduction was over the objections of traffic engineers, who had done a speed study that showed a reduction was not appropriate. Local police reported that drivers obeying the speed limit were causing traffic problems. The speed limit in Eastham was further reduced to 40 in 2001 in direct contradiction to the engineer's report that such a reduction was "not possible" due to 85th percentile speeds near 50.

Provincetown

The speed limit in Provincetown was reduced from 55 to 50 at the same time that other speed limits were reduced in 1997. A followup study found 85th percentile speeds near 60. The road was later discontinued as state highway and the speed limit signs may be illegal unless a speed regulation was approved for the town.

The speed measurements below, except for Yarmouth, are from MassHighway measurements which involved one or more of a car in plain view, wet weather, or recent high intensity enforcement, all of which reduce speeds from the free-flowing speed that should be used for speed zoning. Eastham shows two pairs; the first of each pair is a 1998 speed survey following the speed limit reduction and the second is a 2001 speed survey following intensive enforcement.

Route 7

Sheffield

The Ashley Falls bypass, the two lane limited access section of Route 7 in Sheffield, was posted 60, lowered due to the NMSL, and never restored. The estimated 85th percentile speed is 65.

Lenox

The 60 mile per hour speed limit on the Lenox bypass was lowered from 60 due to the NMSL and never restored. The 85th percentile speed is between 60 and 65.

Lanesborough

In response to a local complaint about traffic speed MassHighway did a study in the mid-1990s and found that the 85th percentile speed was 58-60 in the 55 zone. The speed limit remained unchanged.

Williamstown

The speed limit was reduced in Williamstown despite 85th percentile traffic speed of 50 in the new 45 zone.

Route 8

Sandisfield

Route 8 south of Sandisfield was rebuilt in the late 1960s. An engineering study found 85th percentile speeds over 60 but the new road was posted 55. Current 85th percentile speed remains over 60.

Lanesborough

An engineer reviewing speed zones in 2000 found that the speed limit should be 55, but chose to leave it 50.

Cheshire

A new rail trail crosses Route 8 in Cheshire. The town demanded a speed limit reduction and a traffic signal. After an engineering report said no signal was needed and the speed limit was too low already, MassHighway decided to install a traffic signal and reduce the speed limit.

Route 9

Windsor

The speed limit in Windsor is 55, but MassHighway speed measuring equipment reports an 85th percentile speed of 63.

Williamsburg

The speed limit through Williamsburg was reduced under political pressure, and contrary to engineering advice, in 1972 and 1980. The road is now a major speed trap as it is posted 25 with an 85th percentile speed between 35 and 40.

Natick

The speed limit on Route 9 near Speen Street was lowered to 40 in the early 1980s so the state could appear to be doing something about an accident problem. Following years of complaints from the NMA and others and media reports about the speed trap, the speed limit was raised to 50 in 2005. The new limit is below the engineering recommendation but in places is within the discretion allowed by MassHighway's standards.

Wellesley

The 85th percentile in the rural 50 mile per hour zone in Wellesley is 60.

Route 20

The speed limit on most of Route 20 was reduced by 5 miles per hour, one short segment at a time, in the 1970s and 1980s. Most of these reductions were unwarranted. Only sections with specific speed measurements are listed here.

Brimfield

The speed limit on the divided highway in Brimfield was lowered from 60 due to the NMSL and never restored. The estimated 85th percentile speed is near 65. On the four lane undivided highway east of the center of town, the 85th percentile is 64.

Charlton

Route 20 in Charlton was rebuilt as a divided highway with improved sight lines. The limit had been reduced from 55 to 50 on the undivided highway and that limit remained after improvement. The 85th percentile speed on the divided highway is close to 65.

Sudbury

The speed limit on Route 20 in Sudbury, between the commercial strip and Landham Road, was reduced from 40 to 30 in 1985. A 2003 study by a MassHighway traffic engineer found zero compliance with the speed limit and recommended restoring the 40 mile per hour speed limit. The recommendation was rejected after local and state politicians intervened.

Route 23

In the 1970s MassHighway lowered the speed limit through Egremont from 30 to 25, creating one of the Berkshires' main speed traps. At the time, both speed data and trial runs showed that the limit should be 35. Estimated present 85th percentile speed, despite heavy enforcement, is 35.

Route 28

The speed limit on Route 28 from Bourne to Falmouth was lowered from 65 to 60 in the 1960s, lowered again due to the NMSL, and is now posted 55.

In Milton, the 45 mile per hour speed limit is well below the 56 mile per hour 85th percentile speed.

Route 44

An engineering study done in the early 1970s recommended a 65 mile per hour speed limit on the two lane limited access section of Route 44 from Middleborough to Carver. The limit was posted 55 instead, and lowered to 50 in 1974.

Route 57

The speed limit on the Route 57 freeway in Agawam was lowered from 60 due to the NMSL and never restored.

Route 62

Route 62 in Princeton west of the center of town was rebuilt in 2000 and 2001. An engineering study recommended 50 and 55 mile per hour speed limits on the improved road. After a selectman said he was "appalled" at such high speed limits the road was posted 40 and 45 instead.

Route 63

The speed limit on Route 63 in Leverett was reduced from 50 and 55 to 45 and 50 under pressure from the town and has become a speed trap. Having forced a reduction in the speed limit, the town now takes the position that the speed limit is set by the state and there is nothing the town can do to get it raised.

Route 66

After Route 66 in Huntington was rebuilt in the late 1990s the speed limit was set to 35 based on a trial run by a traffic engineer who found the road safe for 40.

Route 88

The speed limit on Route 88 was lowered from 60 due to the NMSL and never restored. The 85th percentile speed is close to 65 (higher in the off-season, lower during summer).

I-93

Somerville and Medford

Prior to the NMSL the speed limit on I-93 in Medford dropped from 65 to 60. Now the lower speed limit is 55, while the 85th percentile speed in the 55 zone is over 70.

Boston

The 85th percentile speed of free-flowing traffic on the Southeast Expressway is close to 65.

Route 112

The speed limit on Route 112 in Ashfield and Goshen is 55 but the 85th percentile speed is 64. (This road exhibits a literal "rush hour" as speed increases during the morning commute.) In Huntington, the speed limit drops from 50 to 35 at Route 66 but the 85th percentile speed remains 50.

Route 116

The Amherst bypass was lowered from 60 due to the NMSL and never restored.

Route 125

The speed limit on Route 125 in Andover was reduced from 55 to 50 in the 1990s. The 85th percentile speed is 59.

Route 128

In the late 1960s an engineering study found sections of Route 128 suitable for a 60 and 65 mile per hour speed limit, depending on location. The entire highway from Braintree to Manchester was posted 60, except for a reduced speed zone in Peabody and Danvers. The speed limit was lowered due to the NMSL and never restored. Current 85th percentile speeds are generally between 70 and 75.

Route 135

The speed limit on Route 135 in Wellesley, west of town, is 45. The 85th percentile speed is 53.

Route 143

Engineering review of the speed limit on Route 143 in Peru found it should be 50. Instead it was posted 45.

Route 146

Most of Route 146 has been the subject of an engineering speed study within the past 15 years. This is due to reconstruction since the 1960s.

Worcester

The 55 mile per hour posting on the new highway in Worcester appears to be arbitrary; it was posted as an extension of the speed zone in Millbury.

Millbury

An engineering study in 2005 recommended a 65 mile per hour speed limit on all of Route 146 in Millbury, consistent with 85th percentile speeds. Instead the north half of the road was posted 55 and the south half 50.

Sutton to Rhode Island

A speed study in 1998 found an 85th percentile speed near 70. The road was posted 65 instead from Rhode Island to about halfway through Sutton. The speed limit in the north half of Sutton had been 60 until lowered by the NMSL.

I-195

When I-195 was completed in the early 1970s the speed limit was 65 from Rhode Island to shortly before the end of the highway in Wareham. The speed limit was lowered due to the NMSL. Most was posted 65 in 1995, but the 55 limit was retained through Fall River and New Bedford. The speed limit in Fall River was lowered to 45 in 1999 after a piece of City Hall fell onto the highway. The speed survey at that time, while the area was under construction and warning signs were in place, found the 85th percentile speed was 58.

Route 213

The speed limit on Route 213 was lowered from 60 due to the NMSL and never restored.

I-290

The 55 mile per hour speed limit on I-290 in Worcester was lowered to 50 after a truck driver fell asleep and crashed. Possibly the intent was to provide contrast with the 55 mile per hour maximum speed at the time. The 85th percentile speed is 64.

I-291

The speed limit on I-291 was lowered from 60 due to the NMSL and never restored.

I-495

The speed limit through Lawrence was lowered from 65 due to the NMSL and never restored.

The Lowell Connector was lowered from 60 due to the NMSL and never restored.

MDC (DCR) Roads

The policy of the Department of Conservation and Recreation (formerly the Metropolitan District Commission) is not to base its speed limits on engineering studies. In response to numerous requests they have not been able to produce an engineering study for any road under their jurisdiction. There is also no record of any official order establishing speed limits. Whatever was posted when a sign inventory was done in the 1970s was assumed to be correct.

Although not in violation of the state statute requiring MassHighway approval, these speed limits are illegal because they were not based on an engineering study as required by the MUTCD. Courts have ruled in favor of drivers who challenged speeding tickets on this basis. There are no published, precedential decisions so any defense needs to based on an appropriately detailed legal and factual argument rather than a simple assertion that the ticket must be thrown out.

Turnpike

Since speed limits on the Massachusetts Turnpike were lowered due to the NMSL they have not been based on engineering studies.

In one case the speed limit was posted so low that police had to warn drivers not to cause a traffic hazard by obeying the limit! (See the Boston Herald's "Roads Scholar" column from May 10, 2004.)

Cities and towns

Belchertown

Route 202 through the center of Belchertown was transferred from state to town jurisdiction in 1993. Some of the old state highway speed limit signs still remain. These are not legally effective since the change of jurisdiction.

Bellingham

In the 1990s a selectman, offended by the speed of traffic, ordered the speed limit on Route 126 south of town reduced from 45 to 35. This speed limit is illegal. The speed limit reduction was not approved by the state and could not be justified by an engineering study - the 85th percentile speed of traffic is 45, the same as the legal speed limit.

Paine Street near the Rhode Island border is posted 25, but no speed regulation has been approved.

Belmont

Belmont has removed some of its illegal signs, but others remain. Among them are a "THICKLY SETTLED 30", a full-time school zone (school zones may only be in effect when children are walking to or from school), and a square sign on Lexington Street saying "25 MPH".

Blackstone

MassHighway has not authorized Blackstone to post any speed limits. Except on state highway Route 122, every speed limit sign in town is illegal.

Boston

Boston has many illegal speed limits. Beacon Street and Commonwealth Avenue are posted 30 without approval from MassHighway. Washington Street near the Newton border is posted 25 without approval from MassHighway.

The road through Franklin Park is posted 25 without approval from MassHighway. The Mayor ordered strict enforcement of this illegal speed limit after he was nearly hit by a car. The 85th percentile speed is close to 40.

Washington Street near the Dedham line has speed limit signs strategically omitted so that the speed limit appears to be 25 or 30 instead of 40.

Brockton

Brockton has posted illegal speed limits throughout the city. The only city streets for which MassHighway has authorized speed limits are North Main Street, East Ashland Street, West Chestnut Street, and Route 37. In addition, state highway routes 24, 27, 28, and 123 have legal state speed limits, except downtown where they are city-maintained streets. Many of the signs read "FUNDAMENTAL SPEED LIMIT 30." These are illegal for all the reasons an ordinary speed limit sign would be illegal, and also because they are not standard.

Burlington

After Middlesex Turnpike in Burlington was widened the 35 mph limit from the old two lane road was retained. The 85th percentile speed on the new road is 46.

Clinton

Route 110 is posted 30 without approval from MassHighway. The state has not authorized Clinton to post any speed limits.

Dalton

Grange Hall Road is posted without approval from MassHighway.

Dover

Dover prides itself on being rural, but that also would make most of its roads 40 MPH. So in many places they simply post lower speed limits without any approval from MassHighway. One such example is Dover Road, illegally posted 30 despite an 85th percentile speed of 43.

East Brookfield

MassHighway has not authorized East Brookfield to post any speed limits. Podunk Road has illegal speed limit signs.

Franklin

Forest Street is illegally posted 30.

Georgetown

The west end of Route 133 is posted 35, but the authorized speed limit is 40 and 45. A 50 MPH zone near I-95 is not posted.

Holden

Route 31 north of town is illegally posted 30. The legal speed limit is 35 and 40.

Hopkinton

South Street is posted 35. The legal speed limits are 40 and 45, and those were approved before the road was improved to accomodate EMC headquarters.

Hubbardston

New Westminster Road is posted 40 without approval from MassHighway.

Lexington

Hartwell Ave is posted 40 without approval from MassHighway.

Spring Street is illegally posted 30. The legal speed limit is 35, except for a short 30 zone approaching Route 2A. The 85th percentile speed is 41, so even the legal speed limit is quite low. The south end of the road does not have an approved speed limit because the speed zone used to end at an at-grade intersection with Route 2.

Lincoln

The authorized speed limit on Route 126 near the Concord border is 25 in the summer and 35 in the winter. The town posts the lower limit year-round.

As a general rule, any traffic control device placed by the town of Lincoln can be assumed to be for the purposes of harassment rather than safety.

Lynn

Lynn has posted a large number of unauthorized 20 MPH speed limits and improperly posted school zones. These are favorite hunting grounds for city police. There are also a few other illegal speed-related signs scattered around.

Medford

The authorized speed limit on Route 60, Medford, varies between 20 and 30 (30 at either end, then 25, and 20 in the middle). The city has posted the entire road 20 MPH. The authorized speed limit on Route 38 north of Route 60 is 35. The city has posted 30.

Melrose

Several streets in Melrose, including Main Street, are posted 30 without approval from MassHighway. The only city streets for which MassHighway has approved speed limits are Hesseltine Avenue, East Highland Avenue, Derby Road, Waverly Place, and Howard Street.

Milford

MassHighway has not authorized Milford to post any speed limits. The only legal speed limit postings are on the state highways: I-495, Route 16 east of Route 109, and Route 140.

Millis

The east half of Main Street (Route 109) is posted 40, but the authorized speed limit is 45. The 85th percentile speed of traffic is 50, so even the authorized speed limit is too slow.

Milton

Canton Avenue is posted 30 without approval from MassHighway. The only roads with approved speed limits are the numbered highways, Granite Ave. (state highway, former Route 37), and Governor's Road. Note that some roads are under MDC rather than town or MassHighway jurisdiction: Truman Parkway, Neponset Valley Parkway, Hillside Street, Blue Hills Parkway, Chickatawbut Road and Unquity Road.

Mount Washington

The paved roads in Mount Washington have posted speed limits that were not authorized by MassHighway.

Newton

Newton speed limit ordinances are available on the city web page.

As of March 2008 Newton has corrected the speed limit signs posted contrary to ordinance or approved speed regulation.

The engineering study for the speed limit on Lexington Street did not include a speed survey. Instead an engineer noted the presence of a sharp curve and refused to post over 30. That curve has since been flattened.

Where cells are omitted in the table below, the data came from the city and did not include precise location, median speed, and/or compliance rate. Roads without posted speed limits are omitted. The traffic engineer has reported 85th percentile speeds ranging from 27 to 39 on roads subject to the statutory 30 mile per hour speed limit.

North Reading

Concord Street is posted 40 without approval from MassHighway.

Northbridge

Quaker Street near the Upton town line is illegally posted 35. The legal speed limit is 40. The speed limit, as was common practice in the mid-1970s, was not based on a proper engineering study but instead on the presence of a curve.

Oxford

Sutton Avenue is posted 30 without approval from MassHighway.

Pepperell

Brookline Road is posted 30 and 35 without approval from MassHighway.

Petersham

Route 32A is posted 40 without approval from MassHighway.

Phillipston

Route 101 is posted without approval from MassHighway. MassHighway has not authorized the town to post any speed limits.

Randolph

Several roads, including Pond Street and Oak Street, are posted 30 without approval from MassHighway.

Royalston

Route 68 is posted 25 and 40 without approval from MassHighway.

Saugus

Main Street near the Wakefield line is illegally posted 35. The speed limit is 45.

Shirley

Leominster Road and Front Street have posted speed limits that were not approved by MassHighway. The only authorized speed limits in Shirley are on Route 2A (a state highway) and Longley Road.

Shrewsbury

After South Quinsigamond Road was rebuilt and improved town police continued to enforce the old 25 mile per hour speed limit. Eventually traffic court magistrates told them the speed limit was unreasonable and would not be upheld in court. The town reviewed the speed limit. A traffic study found that the speed limit should be 35 or 40. Instead of posting a safe speed limit, the town decided to remove the 25 mile per hour signs.

Swampscott

The town lowered the speed limit on part of Essex Street from 35 to 30 without state approval.

Templeton

Baldwinville Road and Depot Road are posted 35 without approval from MassHighway. The only roads for which speeds limits are authorized are Route 101 and the state-maintained parts of Routes 2, 2A, and 202.

Tewksbury

Chandler Street is posted 30 without approval from MassHighway.

Wakefield

Main Street is posted without approval from MassHighway.

Ware

The town got approval for a 10 mile per hour speed limit reduction on Route 32, and now finds that traffic is moving more than 10 miles per hour over the speed limit. (Springfield Republican, August 29, 2004)

Wareham

Around 1997 Wareham reduced many speed limits without state approval. For example, Minot Road was reduced from 45 to 40.

Watertown

There are illegal 30 MPH speed limit signs on Route 16 (Mount Auburn Street and Watertown Street). The 85th percentile speed is over 35 and the speed limit should be 35 or 40.

West Springfield

Elm Street and Piper Road are posted 30 without approval from MassHighway.

Westborough

Westborough changed the 40 MPH speed limit on Lyman street to 30 without getting approval from MassHighway, and according to the newspaper they did so with full knowledge that they were breaking the law. At first the police said they couldn't enforce the illegal speed limit, but now they enthusiastically patrol this speed trap.

Flanders Road west of the Route 9 connector is illegally posted 30. The connector itself is a state highway, posted 50 despite an engineering study finding the limit should be 55.

Westford

The only roads in Westford on which speed limits are authorized are Cold Spring Road, Power Road (state highway), Route 27, Route 110, and I-495. There are illegal speed limit signs on several other town roads.

Worcester

Worcester posts illegal 30 signs on many streets. Being less densely populated than other cities, Worcester has faster traffic.

Other speed measurements

For completeness, here is a list of known speeds vs. speed limits on roads that are not listed above. All of these have speed limits within 7 miles per hour of the 85th percentile speed, otherwise they would have been listed above. That does not make the speed limit correct. It means the speed limit could be correct if circumstances justified the particular deviation below the 85th percentile speed.