Wednesday, June 27, 2007

I-495 Capital Beltway Traffic

I travel on the outerloop of capital beltway each morning from route 50 to I-270 North. That is, I enter the outer loop at route 50 in Maryland and take I-270 North exit. This stretch of highway commute is probably worst on the capital beltway and probably worst in the Washington metropolitan region. The outerloop comes to a standstill just after the route 1 interchange everyday. I think the main reason for this traffic is the inflow of traffic from the I-95 South that merges into the outerloop after the route 1 interchange. The outerloop has four lanes before the I-95 merge and I-95 comes in with 2 lanes of its own. So, 6 lanes of traffic tries to squeeze into 4 lanes after the New Hampshire avenue. If you are a daily commuter on this highway, you will notice that there is a bridge after the New Hampshire Avenue and just before the University Blvd on the outerloop. Just before this bridge all 6 lanes must merge into 4 lanes because the bridge is not wide enough to accommodate 4+ lanes of traffic.

Here's are the interchanges and traffic patterns on the outerloop every morning:
  • Route 50
  • Annapolis Road (MD-450, Exit 20)
  • Baltimore-Washington Parkway (MD-295, Exit 22)
  • Kenilworth Avenue (MD-201, Exit 23)
  • Baltimore Avenue (Route 1, Exit 25)
  • I-95 interchange New Hampshire Avenue (MD-650, Exit 28)
  • University Blvd (MD-193, Exit 29)
  • Colesville Rd (MD-29, Exit 30)
  • Georgia Avenue (MD-97, Exit 31)
  • Connecticut Avenue (MD-185, Exit 33)
  • Wisconsin Avenue (MD-355, Exit 34)
  • I-270 North (Exit 35)

The backup starts at route 1 interchange (exit 25) and goes all the way to the Georgia Avenue (exit 31). This is about 6-7 miles of stop and go traffic every morning. It takes about 30-40 minutes to go through this 7 mile stretch in the morning. I have yet to figure out a reason why the traffic starts moving at posted speed limit after Georgia Avenue interchange. Does anyone have an idea?


  1. Thank you for your info. i'll be starting a new direction and I have to get on at 95S and then travel the outerloop to exit 41 MacArthur Blvd.
    Do you know what is the best time to leave at if i take 95S to 495?

    I have another option of taking 29S to 495, but not sure if that will be any better? thank you for any help!

  2. I am sorry to tell you this, but once you get on the outerloop of 495, it will take you at least 30 minutes to go about 6 miles to Georgia Ave. And this does not change no matter how early you leave for work in the morning. I have started my commute at 6 a.m. in the morning hoping that it will take less time, but traffic is same no matter what. The rush "hour" starts at 6 am and lasts well into 10 o'clock hour these days.