There are multiple service center locations in Washington DC which you can get different testing done at.  The list of Washington DC emissions testing locations is as follows:

The main inspection station is located at 1001 Half Street, SW

Here is a live view of the Inspection Station waiting line to help you see if now would be an ideal time to visit and get your emissions tested:

Here are directions to this location from different areas:

From Suitland Parkway going North:

  • Take the HOWARD RD ramp toward METRO PARKING.
  • Keep LEFT at the fork in the ramp.
  • Turn SLIGHT RIGHT onto South CAPITOL ST SE.
  • Turn LEFT onto M ST SE.
  • Turn RIGHT onto HALF ST SW.
  • The Inspection Station will be on your LEFT
  • From the DMV Georgetown Service Center (3222 M Street, NW):
  • Go East on M ST NW toward 31ST
  • Follow PENNSYLVANIA AVE (to the right) Pass through 1 circle
  • Take a SLIGHT LEFT onto H ST NW.
  • Turn RIGHT onto 3RD ST NW.
  • Merge onto I-395 South via the ramp – on the left – toward TUNNEL.
  • Follow I-295 toward ANACOSTIA – Stay in the right lane.
  • Take the SOUTH CAPITOL STREET exit.
  • Turn RIGHT onto I ST SW.
  • Turn LEFT onto HALF ST SW
  • From Kenilworth Ave and Benning Rd NE:
  • From Kenilworth Ave, (295)
  • Get onto DC-295 South.
  • DC-295 South becomes I-295 South.
  • Take the HOWARD ROAD exit, number 3B – toward DOWNTOWN.
  • Turn RIGHT onto HOWARD RD SE.
  • Keep LEFT at the fork in the ramp.
  • Turn SLIGHT RIGHT onto South CAPITOL ST SE.
  • Turn LEFT onto M ST SE.
  • Turn RIGHT onto HALF ST SW.
  • From Georgia Ave and Alaska Ave NW:
  • Drive Southwest on GEORGIA AVE toward KALMIA RD.
  • Turn LEFT onto KALMIA RD NW.
  • KALMIA RD NW becomes EASTERN AVE NW/EASTERN AVE.
  • Take RIGHT onto BLAIR RD NW.
  • Stay on BLAIR RD until it becomes North CAPITOL ST NW/N CAPITOL ST NE.
  • Turn LEFT onto HAWAII AVE NE.
  • Turn RIGHT onto North CAPITOL ST NE.
  • Turn RIGHT onto NEW YORK AVE NW/US-50.
  • Turn LEFT onto I-395 S.
  • Take the I-295 exit on the left toward ANACOSTIA.
  • Take the SOUTH CAPITOL STREET exit.
  • Turn RIGHT onto I ST SW.
  • Turn LEFT onto HALF ST SW
  • From the DMV Brentwood Commerical Drivers License Center and Brentwood Road Test Office(1205 Brentwood Road, NE)
  • Start out going SOUTHWEST on BRENTWOOD RD NE toward 13TH ST NE.
  • Turn SLIGHT LEFT onto 9TH ST NE.
  • 9TH ST NE becomes BRENTWOOD PKWY NE.
  • Take the NEW YORK AVE. WEST ramp toward DOWNTOWN.
  • Turn RIGHT onto NEW YORK AVE NE/US-1 ALT/US-50. Continue to follow NEW YORK AVE NE/US-50.
  • Turn LEFT onto I-395 S.
  • Take the I-295 exit on the LEFT toward ANACOSTIA.
  • Take the SOUTH CAPITOL STREET exit.
  • Turn SLIGHT RIGHT onto S CAPITOL ST SW/S CAPITOL ST SE. Continue to follow S CAPITOL ST SW.
  • Turn RIGHT onto K ST SW.
  • Turn Left onto Half Street, SW
  • End at 1001 Half St SW
  • From the DMV Penn Branch Service Center (3220 Pennsylvania Avenue, SE)
  • Start out going NORTHWEST on PENNSYLVANIA AVE SE toward BRANCH AVE SE.
  • Take the ramp toward I-395.
  • Merge onto SOUTHEAST FWY.
  • SOUTHEAST FWY becomes I-295 N.
  • Take the I-395 N exit.
  • Take the D ST SW exit.
  • Turn RIGHT onto WASHINGTON AVE SW.
  • Turn SLIGHT RIGHT onto S CAPITOL ST SE/S CAPITOL ST SW. Continue to follow S CAPITOL ST SE.
  • Turn RIGHT onto K ST SW.
  • Turn Left onto Half Street, SW
  • End at 1001 Half St SW 
  • From the DMV Southwest Service Center (95 M Street, SW)
  • Start out going WEST on M ST SW toward 1ST ST SW.
  • Turn RIGHT onto DELAWARE AVE SW.
  • Turn RIGHT onto I ST SW.
  • Turn RIGHT onto HALF ST SW.
  • End at 1001 Half St SW 
  • From the DMV Adjudication Services (301 C Street, NW)
  • Turn left on 3RD ST NW
  • Make a Sharp RIGHT Turn to take ramp onto I-395 S
  • Take the ANACOSTIA LEFT exit onto S CAPITOL ST SW
  • Turn RIGHT on K ST SW
  • Turn LEFT on HALF ST SW
  • Arrive at 1001 Half St SW, Washington, on the RIGHT