This is a really good episode, it has everything. Multiple good sci fi concepts, horror stories of tech gone wrong and the social impact, great direction, loads of emotive acting, and a great soundtrack.

Throughout the episode we get some really nice writing. At the start doctor’s poetic description of gallifrey gives us a sense of optimism and hope that is bookended really well with the fade out at the very end of the episode. There are multiple lines throughout that end up hinting at the face of boe - brannigan’s joke about a giant head, martha relying on a complete stranger. Hologram Sally’s “we’re so sorry” line echoes the doctor’s catchphrase and you think it’s about the non-functional motorway jam, when it is in fact an apology that they’re the only ones left alive.

The acting and character work is excellent. At the beginning, when they open the tardis door, the doctor appears to break something which is a lovely bit of business that makes their trip seem genuine and unplanned. Martha’s distraught expressions throughout, while still maintaining her competence as a smart person - caring about a pregnant woman and her idea to run silently. Tennant looks incredibly emotive during the doctor’s sad story at the very end. Despite having no real actor present, the face of boe is voice acted really well.

Effects wise, I did find the CGI a bit jarring, and the macra monsters were particularly bad. With the lack of a joke about carcinization, I feel it might have worked better as a lovecraftian unseen monster. But then we get a lot of really great practical effects like very good cat makeup, and close ups of the face of boe that don’t make his head look like just a lump of plastic.

I love the cars as a way to showcase the claustrophobia of both non-functional transport, we’ve all been trapped on a delayed bus or train or plane at some point, but also the limits of technology. Only being able to contact people on your friends list, and being trapped in confined lanes, every car homogeneous. The rumours of hope. The denial. I do have some quibbles though - if the system is automated, why are they even sitting at a steering wheel. And given all the exhaust fumes, they must be getting fuel, but from where?

Really enjoy this episode.

This has alwasy been a favourite of mine - high-concept nonsense at its finest.

The core of a society spending their entire lives in their cars is incredibly on-the-nose, and I love it. RTD does what he does best, creating a world of memorable characters who each seem like they have full lives and personalities, with very little screen time. They really sell the absolutely absurd concept.

I don’t think I’ve heard “The Old Rugged Cross” outside of this episode - Gospel isn’t exactly my thing - but it’s used well here, and I’m surprised to learn that it’s an American song, and not something with British roots.

The “mood dealers” are an interesting idea, but somewhat underbaked. It seems like something they could have done more with, but here they’re mainly a plot device to explain what happened to the overcity.

The idea of the Doctor bringing Martha back to New New New New New New New New New New New New New New New York is pretty solid, though I wish Martha didn’t complain about it the way that she does. The unrequited crush angle continues to underwhelm, even though it’s handled better in this episode than elsewhere. It’s helped along by the fact that we can see the Doctor fighting with himself, slowly opening himself up to her against his own better judgement.

It’s also nice to see the Face of Boe one last time - I’ve always felt that the character is diminished by the Captain Jack connection, and treat him as a separate character.

Oh, and Sally Calypso deserves her own spinoff based on her name alone.