I JUST got one of these f*****' things in the mail dated 11/5/19, and yes, the speed limit in that area dropped by 10 mph in May of this year. The orange signs posted say "Work Zone", but all the "work" seems to be taking place a mile or two ahead - when you see any at all.
DC is seemingly one big "work zone" covered in orange barrels and yellow lane-terminating signage, so it's a never-ending gauntlet and gives the city justification for said money-grab mentioned above. It fills the city's coffers with predatory revenue... https://www.washingtoncitypaper.com/news/article/21022176/dc-traffic-tickets-the-district-profits-and-residents-pay
Sad thing is I live not too far from that particular camera on 295 and KNOW it's there, but all it takes is a momentary distraction or lapse in attention and boom! They got you because "camera cops" (as I unaffectionately call them) are omnipresent in DC. Some blocks have multiples. They even have them now for STOP SIGN right turns. Apparently the cameras count the 3-4 seconds you're required to come to a complete stop and bang you via mail in a week or so if you're too eager to make that turn.
Don't ignore the ticket, because it WILL double. Since I live here in the DMV and have gotten a few of these nuisance tickets over the years, I've found that rather than pay it right away, you can submit an
online appeal (same area you'd ordinarily pay online) with any explanation (ridiculous or sublime) you care to. What you write isn't as important as
THAT you submitted something prior to the 30 day deadline. The hopeless bureaucracy of DC's process has a ticket I addressed this way back in June (on Father's Day interestingly enough) still under review. Who knows if/when they'll ever get around to adjudicating it, but if nothing else it buys you some time before having to swallow that big ole $200 bitter pill. Good luck, and Lord knows, you have my sympathies.