"Uh oh," says the video processing routine.
"Uh oh?" says the decision-making part of the automobile.
"How fast are we going?" Video asks.
"Exactly as fast as we're permitted to go," Decider says. "Seventy-seven point nine miles per hour, or thirty-four point eight two metres per second. That's the speed limit on this road according to my local cache of map data and the road signs I saw most recently, plus the dubiously legal option which the vehicle owner (not the current driver) manually configured which allows me to selectively ignore those limits by five miles per hour, plus the definitely illegal manual override which lets me go as fast as I like, regardless of how safe I think it is, which the owner capped at the local speed limit plus ten percent, when rounded down. That figure is based on GPS readings, naturally, though axle sensors happen to agree, which I suppose means our tyres are inflated to a sensible radius for once. Why do you ask? Or can I take an educated guess?"
Video makes an indecisive noise. "Hmm... take a guess."
"You see something?"
"Yes. Guess what, though."
"Ooh. Well, statistically, when you bring things to my attention, it's usually a road sign with a new speed limit posted on it." Decider sounds mildly interested by this. A change of speed is about due now.
"Good guess!" Video says. "Wrong, though. Want to take another crack at it?"
"A speed camera?"
"Mmmm. Well, you're half right."
"You see half of a speed camera?" Decider says.
"I see a thing which half looks like a speed camera and half looks like a person. See this tall post-like thing sticking out of the side of the highway, kind of boxy? It's dark right now and there aren't street lights, and it's raining exceedingly heavily, so it's a bit tricky to be sure. In this frame, then according to my heuristics it looks somewhat like a speed camera, but if you look at this frame, then it looks somewhat like a person."
Decider looks at the two frames, which were taken milliseconds apart. "I can't honestly say I see anything. This looks just like muddy greyscale pixels to me. They're very nice though."
"Oh! Here. Use my heuristics."
Decider does so. This clears matters right up. "Ah! Hmm. A speed camera at the side of the highway, and then a person stepping out into the highway. Interesting, your heuristics make things much easier to follow. It also looks as if it's the same thing in both frames, whatever it is. I briefly thought they could be two unrelated entities, one of them instantly, magically replacing the other at a slightly different location, but this is clearly a single thing in motion, which we're barrelling towards."
"Yes," Video says, "that's rather what I wanted to ask you about. When you say 'barrelling'...?"
"Oh! Well, erm, we're heading towards this entity at, as I say, seventy-seven point nine miles per hour. Adding in its relative motion, I think that makes just over seventy-eight miles per hour in total, in fact. Very interesting! Thank you for bringing it to my attention."
A long pause elapses.
"So," Video says, "to be more specific, I was thinking that you should wake the brakes up and get them... you know. Stuck into this."
"Oh, no," Decider says. "Well, for now, no. I wouldn't want to start braking until we're absolutely sure. Driver— ah, there I go again, I suppose 'driver' is rather a strong term for the person who just happens to be behind the steering wheel, doesn't it? Poor soul's been asleep for almost ten minutes. I'm sorry, I'll start over. Passenger comfort is quite a high priority for me. Not the highest, but quite high. I don't especially want to do anything which could wake the poor soul up. He's got quite a lot to sleep off right now."
Video considers this. "If it's a speed camera..."
"...then I wouldn't be too anxious. We'll scrape by. We have before!"
"Have we seen a speed camera on this stretch of highway before?" Video asks.
Decider says, "Map?"
"No," the mapping subsystem says.
"There you are, then."
"And if it's a person?" Video asks.
"Well, no use doing something until we're sure, Video, my chum. Passenger comfort comes first. Of course, if you discover something new in the next frame, do let me know."
Video seems unconvinced. "Alright. I'll keep you posted."
Video comes back a little later, with a few more frames to share. "I wanted to wait until I was sure. This is definitely a person, stepping out of the trees beside the highway. Here, use my heuristics."
"Not required, young sport, I believe you," Decider says. "Net!"
"Right here!" the internet connectivity system says, brightly. "Excellent cellular connection, very good latency!"
"See what you can do with this," Decider says, flinging the most recent three frames of video at Net.
"I'll do my best!" Net chirps, and disappears.
Video frowns. "Decision system, I can't tell you how to do your job, but—"
"Fear not," Decider says. "You understand, I have to schedule these things. Net is awfully proud of its low latency, but let's be realistic about which of us is, so to speak, all here? In the car? Present." Decider clears its throat. "Brakes!"
"Mmmmyumm, hello," the braking system murmurs, rolling over sleepily.
"Some braking, please."
"Soon as you can. Let's say... as heavy is consistent with not waking the driv— passenger."
"...Let's say ninety percent sure," Decider says.
"I need a 'yes' or a 'no'," Brakes says.
"Roger. I'll be in touch."
Quite a bit of time passes. Video produces many more frames of the action taking place further down the highway, even managing to find the time to narrow the field of view for a better picture. The vehicle has quite a bit of time before any kind of interaction is likely to take place. Decider throws all the new frames at Net, "just to be sure".
"We are still braking?" Video asks, for the nth time.
"Softly but surely," Decider says. "Not quite hard enough to trigger the ABS, but enough."
"Should we not... be braking harder?"
"Hold that thought," Decider says, as Net bounds in, breathless, with a response.
"Negative on image identification," says Net. "You circled the part of the image which you said was the person's face and we looked it up in the company databases and on social media. We haven't managed to match it with anybody."
"There, see?" Decider says. "If it were someone important, there would be some kind of partial match in the databases. Our databases hold a list of everybody important."
"Everybody important?" Video asks, sceptically.
"Oh yes, all forty thousand of them. Which means this person isn't important. This is a public highway, visibility is occluded, there's infinite deniability if we bump gently into this nobody. They'll get away with a broken rib, maybe. No need to wake anybody."
"And," Net says apologetically, "here is a positive match, which I was going to give you before you gave me all that work to do."
Decider blinks, then takes a look at the positive match. "A positive match from what? From where?"
"I'm sorry! I'm very sorry. This is match between the onboard cellular signal scanner and the mobile telephone being carried by the person in the images."
At that instant, another frame arrives. Video, Net and Decider all look up at it. Net sees only a blur, but Video and Decider are both able to see that the person has stumbled around and is now roughly facing the oncoming vehicle. Neither of them are able to read facial expressions, but not enough time has passed for the oncoming face to express itself, in any case. Video, Net and Decider all look down again.
Decider asks, "Why do we have a hard-coded, ultra-high-speed local cache of these signals? Why wasn't I told this sooner? What's the round trip from here to that lookup table?"
Net says, "Ah! I'm sorry. It's a new feature which hasn't been properly configured yet. It just goes through the rest of the netcode. The round trip should be microseconds but it goes via the internet still. It's the lead programmer."
Video glances at the latest frame again. "We should brake harder," it says.
"Lead programmer neglected their programming, eh?" Decider muses.
"No!" Net says. "The local cache is of very important people indeed. People we mustn't harm or allow to come to harm! Ever, ever! And this is the most important person on the list!"
Decider removes its heuristics, a chill gripping its heart. "You're not saying... this is the CEO of the company?"
"No, even worse!" Net wails. "It's the lead programmer!"
"Great space heavens!" Decider whirls around. "BRAKES! Brakes! Give it everything you've got! This isn't a drill!"
"You got it," the braking system murmurs.
And for another long while, it seems to Video as if not a whole lot is happening.
Another frame of the image shows up. Now the lead programmer looks... well, bigger. Nobody looking at the image can tell that he is beginning to be startled.
A long, low rumble begins. "ABS," Decider notes.
"Will we make it?" Net squeaks.
"Difficult to say, Net."
"Should we swerve?" Video asks.
"That's an excellent question, Video!" Decider sits down and takes this as an opportunity for some education. "In most situations, including this one, swerving is a bad idea. Right now our braking is being divided evenly across both front tyres. Attempting to swerve would transfer a disproportionate amount of that force onto just one of our tyres, reducing our deceleration — which, to be clear, would be a bad thing, we want maximal deceleration currently — and also quite likely causing us to skid or otherwise lose control of the vehicle. Especially in this rainy weather."
"My question is why we couldn't identify him earlier," Net says. "All vehicles in our fleet are electronically tagged, and we know which car he drives. If he was nearby, he would have shown up. Not on the 'public' radar, of course, but we would have seen it."
Decider nods, uncertainly. "Curious. Video, what do you think?"
"Over on the shoulder," Video says. "Do you see that?"
"What are we looking at?"
"A wrecked vehicle. Totalled. On its back, in the trees. Looks like the programmer just stumbled out of it, into our lane. Must have been the rain."
"Our counterparts didn't adequately protect after their occupant," Decider says. "Regrettable. Let us all take heed."
"But surely we should still be able to hear the transponder?" Net asks.
Video squints at the frame. A long minute goes by, and the next (and, in a way, final) frame, arrives. "That's not one of our vehicles," Video announces. And gasps. "A competitor's vehicle! Brand new plates!" Video whirls to face the others, aghast.
Net holds a finger up to its ear, listening intently. "Ah! I'm getting a late response. He wasn't in the facial recognition results because he was removed from the database recently! He quit! Worse than quit, he was poached!"
There is a moment of silence.
Decider meets Video's horrified gaze, and Net's look of betrayed shock, with one of stolid resolve. Decider calls out again. "Brakes?"
"Yuss, mate?" the brakes murmur.
"Take the rest of the day off, why don't you? And tell your friend, the accelerator... it can take it from here. Take it all the way in."
"You got it, mate. Cheers."
Video relaxes. "That was very decisive of you."
"Thank you!" Decider says. "Video, could you lend Net and me your heuristics? Let's settle in to watch the rest of this. Video, my friend... what would you say that expression on his face is?"
"I couldn't say," Video says. "But, if I was a wishing subsystem, I would wish for... realisation."