Interchange Index
I-95, US 1, US 1 Bypass, and ME 236
Kittery, ME
Overhead Picture from terraserver-usa.com
Overview: The major expressway running from southwest to northeast is I-95. US 1 runs parallel to I-95 north of the interchange, and then turns south at the traffic circle (the road farthest to the east). South of the interchange and the traffic circle, US 1 Bypass runs parallel to I-95. ME 236 runs northwest to southeast through the interchange, over I-95 and US 1 Bypass, and through the traffic circle.
On I-95 northbound, exit 2 is for US 1 Bypass, US 1 south, and ME 236 east. Exit 3 serves US 1 North and ME 236 west. I-95 southbound has one single exit, marked as Exit 2. These exit numbers will probably change in the near future, when I-95, I-295, and I-495 are renumbered and their exits are converted to a milepost numbering system.
Interchange Description: I-95's connections to other local roads are not as straightforward as they may seem. ME 236 east, US 1 Bypass, and US 1 south can all be accessed from the right-turn-only ramp from I-95 northbound to ME 236 eastbound or from I-95 southbound. US 1 north is accessed from I-95 southbound via ME 236 and the traffic circle. I-95 northbound traffic bound for US 1 north has its own ramp, which intersects US 1 inside its spread median. Likewise, US 1 northbound traffic can enter I-95 northbound via a left-exit ramp; all other traffic for I-95 northbound enters US 1 northbound through the traffic circle, and then uses this ramp.
Traffic bound for I-95 southbound from US 1 southbound gets its own ramp over I-95. However, this ramp merges into a collector/distributor road, which serves to eliminate from I-95 the weaving between this traffic and traffic from I-95 using Exit 2. Other traffic bound for I-95 southbound can enter the traffic circle, travel northwest on ME 236, and enter I-95 via a left turn.
Traffic switching between ME 236, US 1, and US 1 Bypass generally uses the traffic circle. Note that traffic from the circle can directly access US 1 north via an extended right-turn ramp, and US 1 Bypass via a cloverleaf loop. However, traffic from US 1 southbound must exit to ME 236 near its intersection with I-95, and then turn left and follow ME 236 to the traffic circle. As a final note, there are two roads running southward out of the traffic circle. The easterly of the two is US 1, and the westerly (between US 1 and US 1 Bypass) is the Old Post Road.
Advantages: This interchange does a great job of providing parallel access between US 1, US 1 Bypass, and I-95. All of these movements, with the exception of the ramp from US 1 southbound to the traffic circle, can be made without stop signs or stoplights. In the simplest configuration, which would have been a diamond interchange and the traffic circle, many of these movements would have involved multiple at-grade intersections controlled by stoplights.
Disadvantages: One main disadvantage of this design is the weave that occurs on the collector/distributor road for I-95 southbound. Traffic entering from US 1 southbound and northbound, ME 236 eastbound, and US 1 Bypass crosses all of the traffic exiting at Exit 2. Traffic moving from the traffic circle to I-95 northbound also must weave across all of the through traffic on US 1 Bypass northbound. Likewise, ME 236 has two smaller weaving sections: eastbound, between the ramps from I-95 and the offramp to US 1 Bypass; and westbound, between the ramps from US 1 and I-95 northbound and the ramp to I-95 southbound.
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
