I'd like to see a B-W Pkwy. study that looked at interchange improvements, such as these, where the interchange configuration serves as a source of congestion:
1. Solve the weaving problem SB between the MD 193 and I-495 interchanges due to the closely spaced interchanges. Traffic merging on from MD 193 conflicts with traffic exiting onto I-495 WB. The situation NB isn't much better.
It's better than it was before the Parkway was reconstructed in the 1990's, though still not great.
If you look closely at the south side of eastbound Md. 193 just before the Parkway underpass, you should be able to see that there was once an on-ramp to the southbound Parkway from Md. 193 eastbound. I believe it was removed when I-495 was built in the early 1960's. Putting that ramp back so traffic from Md. 193 could get to the Outer Loop of I-495 (I-95 N) would remove some traffic from that weave.
2. Solve the northbound evening rush hour back-up at the Powder Mill Rd. interchange from merging traffic. Just a half-mile ahead, a 3rd lane begins quite early for all the Laurel traffic exiting onto MD 197. I'd like to see if the benefit of connecting the Powder Mill Rd. on-ramp to the MD 197 off-ramp as a 3rd NB lane would justify the cost. It'd give merging/exiting traffic about a whole mile to safely merge, perhaps at freeway speeds instead of at the current, near stand-still. On the surface, this looks like a high-benefit/low-cost solution. There is a similar but less severe problem southbound during the morning rush hour.
All of the workers getting out of the NASA/Goddard Space Flight Center (and to a lesser extent, the U.S. Secret Service facility on Powder Mill Road and the USDA/BARC) want to enter the northbound lanes of the Parkway, and adding a third lane between Powder Mill Road and Md. 197 would almost certainly help.
3. Solve the back-ups at the MD 32 and I-695 interchanges, which are each old-style cloverleaves that trigger back-ups from the weaving problem at the loop ramp connections to the through lanes. A modern (though expensive) freeway-freeway interchange might solve or alleviate these problem spots.
Agreed regarding the Md. 32/B-W Parkway interchange. Fort Meade is one of the largest employment centers in the state, and a more-modern interchange there would help. As would more lanes on Md. 32 and the Parkway.
Unfortunately, north of Md. 175, the Parkway is part of the Maryland State Highway Administration's network, and beyond what the USDOT/FHWA are looking at.