
A few days ago, one of the frequent commentors on MDP, Jess, started her own daily photo site: http://www.pittsburghdailyphoto.com/ , and despite whatever football related rivalry we might have, MDP wishes her the best in her daily photo persuit. In fact, to celebrate the new site, MDP is fulfilling Jess’s wishlist request from a year ago: posting a picture exemplifying the grand nature of Maryland’s highway onramps.
This is the Stack. The four levels of highway seen here carry 2 (really 1.5) interstates and 8 on/off ramps. To the right, on the top of the stack is I-70, below it is one level of raps, viewable in the bottom left, then in the far left, you can see the ramps that pass one layer below, and finally just above the bush in the bottom center, you can see a piece of I-695.
What’s interesting and unique about this is that these three elevated levels and their seemingly complex intertangling is that they actually make things easier for the driver. Why?? Becasue there are no points in this intersection with a circular 270 degree turnaround. Instead. Every ramp just flows off of the right side of the feeding highway, makes a gradual left turn, goes through the stack, and ends up on the right side of the destination highway.
While it’s great for the driver and for the flow of traffic as it requires less of a speed reduction, it is a bit of a pain to build a four level interchange. Plus it’s visible for a good distance in each direction. So, you want to make sure that you only build it in a location with decent traffic, where it will make a difference.
That’s the unfortunate part. The stack was finished in 1965, according to the markings on the top level. However, protests to the completion of I-70 through baltimore during the 70′s led to the final cancellation of I-70′s route through Baltimore. As a result, I-70 would terminate at the stack. To this day, the upper ramp that carries 70 and the flyover ramps that service it get minimal use. The stub of what’s left of I-70 to the east (like on I-95) became a park and ride with an amazingly effective means of entering and exiting.