I'm glad to see Gridlock getting some love in the reviews. I think it definitely deserves it. Though technically a sequel of sorts to New Earth, I appreciate how nicely Gridlock stands on its own. I also like how the story both captures the frustration of being stuck in traffic but also takes it beyond realism into a bunch of gags and science fiction ideas. The Doctor's performance, along with Martha who is pretty great here, both elevate what could be pretty standard Doctor Who material, but they aren't alone. Most of the performers are also really strong here, there's some decent world building with that larger narrative that doesn't feel overplayed, it's just a good, strong, and somewhat underrated episode overall.

The special effects can be a little inconsistent with stuff like the giant crabs, and that's where the story loses me a bit, but the overall narrative on the whole works, especially the detail of how fundamentally pointless the traffic was to begin with. Gridlock is written fairly well overall but the cast and crew turn it into something special. I would recommend.