Sci-fi novel involving parallel universes and possible time travel

Question

I'm trying to identify a science fiction novel I read many years ago but whose title and author escape me.

I think it was borrowed because I went through all my books, but I couldn't find that one.

Here's what I remember:

• Time of Reading: Late 20th century or early 21st century.
• Age of the Work: The novel appeared quite old when I read it.
• Major Themes: The story prominently featured a parallel universe and potentially time travel, though I'm not entirely certain about the latter.
• Details: The narrative was written in a way that took many things for granted, which struck me. It took a while for me to realize that it was set in a parallel universe or that the main character was from a different universe than ours. This realization came gradually and was solidified by an episode involving semaphores for traffic control. This detail, merely a passing thought from the protagonist, contrasted with his original universe where police officers managed traffic. It was one of the initial hints of an alternate universe.
• Possible Plot Element (Uncertain): There's a possibility that the main character ended up in Georgia, the country in the Caucasus region, not the U.S. state. However, I am uncertain if this is a different story or part of the same novel.
• Setting: The narrative revolved around alternate realities, with the protagonist likely trying to return to their original reality.
• Characters: The protagonist seemed to be an (unwilling?) traveller navigating these realities. No specific names are remembered.
• Language: Read in Italian, and it was likely a translation from American English.
• Exclusions: I'm unsure if the plot included a scene where the main character witnesses the opening of the Strait of Gibraltar, questioning whether this is from the same book or another. This novel was not the Pliocene Exile saga, "The Time Ships" by Stephen Baxter, or "The End of Eternity" by Isaac Asimov.
• Other Details: A well-known, mainstream author likely wrote the book.

Answer 1

Robert Heinlein's 1984 Job: A Comedy of Justice features a main character who unwillingly is shifted from alternate universe to alternate universe - in one universe he sees traffic lights, which his original universe does not have and he muses about how unnatural it is for people to obey a mechanical signal rather than interact with a human traffic officer. Because some of the alternate universe are considerably more primitive than ours, some of the book may have seemed like time travel.

Quote from a section when the hero is explaining traffic lights to someone from a world without them:

"We sat down at a table across from each other, like right now, and that put me facing a set of traffic lights-"

"A set of what?"

"A set of traffic signal lights, red, green, and amber. That's how I spotted that we had changed worlds again. This world doesn't have signal lights , or at least I haven't seen any. Just traffic cops . But in the world we got up in this morning, instead of traffic cops, they do it with signal lights. "

"Sounds like they do it with mirrors."

Another quote on the topic:

With no policemen anywhere around people obey these blind and dumb bits of machinery as if they were policemen. Are people here so sheeplike and peaceful that they can be controlled this easily. No. I wondered about it and found some statistics in the library. This world has a higher rate of violent crime than does the world in which I was born. Caused by these strange lights? I don't think so . I think that the people here, although disposed to violence against each other, accept obeying traffic lights as a logical thing to do. Perhaps. As may be, it is passing strange.

Answer 2

This is something of a long shot, but I'm wondering if you have conflated two stories from the anthology Down in the Bottomlands and Other Places by Harry Turtledove and L. Sprague de Camp.

There is a story called The Wheels of If about a man called Alistair Park who wakes up and finds his world has subtly changed:

Allister Park rubbed his eyes and sat up in bed, as he usually did. He noticed nothing wrong until he looked at the sleeve of his pyjamas. He could not recall ever having had a pair of pyjamas of that singularly repulsive green. He couldn't recall having changed to clean pyjamas the night before. In short, he couldn't account for these pyjamas at all.

Oh, well, probably, Eunice or Mary had given them to him, and he'd put them on without thinking. He yawned, brushing his mouth with the back of his hand. He jerked his hand away. Then he cautiously felt his upper lip. He got out of bed and made for the nearest mirror. There was no doubt about it. He had a moustache. He had not had a moustache when he went to bed the night before.

and Alastair does notice traffic control using semaphores:

The buildings were large but low; Park saw none over eight or ten stories. The traffic signals had semaphore arms with "STAI" and "COM" on them.

The first story Down in the Bottomlands is set on an Earth where the Mediterranean never flooded and it's a depression known as the Bottomlands. The protagonist Radnal vez Krobir is trying to foil a plot to open the Straits of Gibraltar and flood the Bottomlands.

Answer 3

Have read an account of the straights of gibraltar opening in fiction (described the dust cloud that came first? ) I would say it’s either Stephen Baxter’s ‘Space’ or ‘Time’ both novel titles just one word.excellent reads!