Interchange Index
I-90, I-95, and MA 30
Weston, MA
Overhead Picture from terraserver-usa.com
Overview: Interstate 90 is the major east-west highway here; it is part of the Massachusetts Turnpike, and the eastern barrier toll booth for the ticketed portion of the Turnpike appears just east of I-95. I-95, also known as MA 128, is the major north-south highway here; it forms most of a beltway around the Boston metropolitan area. MA 30, a major 2-lane highway running from near Worcester to downtown Boston, heads through just north of I-90, intersecting I-95 in a cloverleaf interchange. A railroad runs through wouth of I-90, and crosses the turnpike at the far eastern edge of the photo - these tracks carry commuter trains bound for Worcester and Fitchburg. This interchange is exits 14 and 15 from I-90: exit 14 is marked eastbound only, and exit 15 is marked wesbtound only. (Technically, it's the toll booths that are numbered, not the exits: 14 is the booth on the exit itself, and 15 is the barrier toll on I-90); from I-95, I-90 is exit 25, and route 30 is Exit 24. Two other exits on I-95 are visible here: exit 23, a northbound-only exit for Recreation Road, is just south of the railroad tracks, south of I-90; in the far southeast corner of the photo, an onramp from Exit 22, Grove Street, is visible. The river here is the Charles River, which eventually flows a little further downstream and winds up separating Boston from Cambridge.
Interchange Description: This interchange is a many-times-removed cousin of the time-honored double trumpet interchange, which is usually used to connect a tollway with a ticket toll system to another freeway. However, a number of modifications were made: I-95 has a long collector-distributor road on the northbound side, I-90 has a barrier toll booth for the mainline thrown in, and MA 30 and a few local streets add to the confusion.
Let's start with I-90's half of the interchange. It is basically a 3-way, semidirectional interchange, where the connector road from I-95 splits before meeting I-90. Traffic going between I-90 to the west and I-95 has its own toll booth on the connector road; at this toll, the Massachusetts Turnpike ticket system is used, and motorists must pay toll EB or pick up a ticket WB. I-90 has a barrier toll just west of the I-95 exit ramps; mainline traffic also pays a (higher) toll EB and picks up a ticket WB. However, traffic going between I-95 and I-90 in the Boston (eastern) direction doesn't get away without paying; two smaller toll booths on either side of the mainline serve these motorists, where they must pay cash in either direction to use the Turnpike between I-90 and the next exit to the east. This toll barrier is known as the Weston tolls.
The connector road between I-90 and I-95 was once a distinct road, which was used by all traffic traveling between the two highways. Now, the 3Y at I-90 and the trumpet at I-95 overlap slightly. The ramp from SB I-95 to I-90, which goes directly over part of the MA 30 cloverleaf, joins the connector just as it splits between I-90 EB and WB. This results in less weaving on the connector road (none at all for 95 -> 90), which is, of course, more desirable. The 90 -> 95 traffic has no advantage like this one, as the merge between I-90 EB and WB comes a little before the split at I-95.
Lastly, there's a bunch of stuff on I-95 to talk about. From the south end, the first interchange is Exit 22 at Grove Street; this is off the southern edge of the photo, but it's important nonetheless. The northbound onramp from Grove Street doesn't join I-95 directly. Instead, it merges with a collector-distributor road for I-95 NB. These C/D lanes are for Exits 23, 24, and 25 northbound. Exit 23 is simply a pair of trumpet-esque ramps for Recreation Road, which runs parallel to and just south of the railroad tracks. Exit 25 (note the out-of-order exit numbers; I'm not sure why) is the large pair of trumpet ramps for I-90. Exit 24 is one offramp, which meets MA 30 at a signalized intersection; there are two onramps from MA 30.
Southbound I-95 is a different story entirely. River Road closely parallels the interstate as it approaches MA 30, preventing any immediate offramp. The first onramp, a loop ramp, actually joins the Exit 25 offramp for I-90, and not I-95 itself. The I-95 offramp for MA 30 is a loop ramp, which meets MA 30 at a four-way intersection shared by River Road; the I-95 SB onramp is right next to it. There is no exit 23 southbound, and Exit 22 is south of this photo's coverage.
History: I believe this interchange began as a simple trumpet interchange, with I-90 entering from the west as the Massachusetts Turnpike and ending here at MA 128. Later, as the Massachusetts Turnpike was extended into Boston, the interchange was extended to its current configuration. (I don't have many specifics on this yet... maybe someone from the area could help me out a little bit...)
Comments: There's not a real lot to say here - it's a pretty well-built interchange, but nothing absolutely spectacular. I like the ramp from I-95 southbound to I-90: the bridge over half of the MA 30 cloverleaf is a good way to avoid weaving between MA 30 onramps and the I-90 offramp. The northbound collector/distributor lanes are also farther from the NB mainline than any other ones I've ever seen - there's quite a bit of real estate in the middle. Some of the loop ramps are kind of tight; the ramp from I-95 south to MA 30 is signed as 20 mph, and is much too sharp to be taken at any reasonable speed. Another minor disadvantage, which is compounded by the location, is the high number of bridges. For example, check out the eastern half of the I-95 trumpet: the loop ramp must cross over the Charles River twice, and it goes right over the C/D lanes and I-95 at the same time. I-90, meanwhile, heads right over this on its own bridge; this crosses I-95, the C/D lanes, the Charles River, and finally the I-95 loop ramp. All these bridges must have made the cost of the interchange really add up...
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Corrections? Suggestions? More information is always welcome.
Suggestions for more interchanges to cover on this site are great too.
Contact the author, Dan (known as DanTheMan on misc.transport.road):
twowheel@email.com
