Ray Alcalde, the mayor of the great megalopolis Los Ancholess, moved his hands slowly across his face, then up over his head. “OK, so tell me how the hell we got almost 200 cars all crashed into each other, dozens of fatalities, hundreds of injuries, and thousands of people snarled in traffic on a completely shut down interstate. Is this a terrorist act?”

Mercedes Ford-Lincoln, the traffic supervisor of the great megalopolis of Los Ancholess, replied, “No sir, we don’t think so. Computer error. Errors, really.”

Ray slumped into his executive overstuffed chair, one of the best things to slump into. “Well, Mercedes, explain it all to me, but keep it as simple as possible.”

Mercedes sat a few seats away from Ray, where she could plug her PC into the overhead video cable. A moment later, a highly colorful, detailed display of Interstate 1110 promised anything but ‘simple as possible.’ Chip Copper, the police chief, dimmed the lights and everyone braced themselves for technical details.

Mercedes began her presentation with the most depressing words possible. “It’s complicated, what happened.” Her laser pointer circled a car-shaped object in the upper left corner. “From what we can tell, this is the car that started it all. High wind blew a piece of debris into the highway area, and traffic camera footage shows that this debris moved close to street level. Like all the other cars on the 1110, this car, a Fnord Festivus, was doing 75 miles per hour and its programming to handle a situation like this was to swerve into the lane with the least traffic.

“Lanes on both the left and right were pretty congested, it being rush hour, but the lane to the right had the least traffic, so it went there, sideswiping a Hando Mimic and a Toygoata Quandry. The Mimic, in front, was programmed to shift to the nearest shoulder in the event of a minor collision – as was the Festivus – so both began to slow down and shift to the right.”

Ray interrupted. “But the nearest shoulder was two lanes over, to the left.”

Mercedes nodded. “Yes, but it was closed for maintenance. The nearest available shoulder was four lanes over, to the right. This would have already caused major issues had it not been for the other, contributing factors that compounded the issue.”

“OK, Continue please.”

“All right…” Mercedes scanned the display to find her place again. “Now, the Quandry was programmed for a right shift for a minor accident, but the drivetime recorder shows that it recorded a major accident, so it rapidly decelerated. The Brewick Regalia behind it noted the slowdown and also began to decelerate rapidly, as did the Evolvo Landtrain behind it. Unfortunately, the Evolvo’s brakes experienced a failure.”

Chip had a word to say about that. “Hold on, those trucks are supposed to have a governor that won’t let them on a road or even take on cargo if there’s a system issue like that.”

Mercedes dipped her head. “We contacted Evolvo about the governor code and they’ve informed us that there’s a flaw in it that didn’t catch this particular kind of stress that would lead to failure. They’re shipping a patch, but that doesn’t help us right now.”

Chip’s eyes widened. “How many trailers were in the landtrain?”

Ray groaned, “Three.”

Everyone was quiet for a moment, then Mercedes continued. “So, this was where our first fatalities came from.”

Chip reddened. “Those landtrain things should not be allowed, I’m telling you. The ICC gave in to the trucking companies and now we’ve got this! Safer with no driver, my ass!”

Mercedes struggled to keep her composure. “I’m with you there. It’s not the first time a landtrain’s been in a big wreck, but this is the biggest one, by far… and it got bigger when the school bus – here – hit it square in the back trailer, causing the three trailers to swing to the left, blocking all the lanes to the cement barricades.”

Ray looked at the Los Ancholess school superintendent, Summer Halladay, and said, “You got an explanation for this?”

Summer got real defensive, real fast. “That truck was going at full speed, there was no indication that it was slowing down. The motion sensors on the bus were doing their job. There was nothing more that could have been done. School buses are programmed more for elaborate pedestrian situations, not freeway traffic.”

Chip asked, “So why don’t buses have a Trafficnet (TM) transponder for when they do go on the freeways?”

Summer’s defensiveness grew more entrenched. “Trafficnet (TM) is a bit high-end for us in Los Ancholess Consolidated Unified Independent School District. Especially after the last round of budget cuts. Besides, not everyone else on the road has it. And it’s not perfect, either.”

Mercedes added, “As it was, Trafficnet (TM) had a glitch in it that compounded matters on the day of the collision.”

Chip asked, “How so?”

Mercedes advanced her slides to show the moment of the Evolvo’s collision. “When the Evolvo hit the Regalia, the Quandry, and the Festivus, all four of their Trafficnet (TM) transponders went offline. All four were in the same lane, so all the Trafficnet (TM)-equipped vehicles on the 1110 immediately behind the collision detected that absence as the lane being less congested and so started on a redistribution algorithm.”

Ray: “A what?”

“Redistribution algorithm. They, ah, moved to adjust to what they thought were more open conditions. Lots and lots of lane changes. Uncoordinated lane changes. Trafficnet (TM) didn’t really have a good method of handling sudden disappearance of fellow transponders, so it acted as though each car, alone, was making a lane change choice, even though all of them were making that change. So, every vehicle with Trafficnet (TM) in the area started to make a move to get into or one lane closer to lane 3, here. That shifted things to converge to where the school bus hit the landtrain.”

Ray asked, “So why didn’t the cars slow down, instead? If the trailers had swung out to block lanes 1 and 2, with the collision in lane 3, shouldn’t everything have initiated a slowdown, at least in those lanes?”

“They did, in cars without Trafficnet (TM). The Trafficnet (TM) cars were running that program with a higher priority than the manufacturer-installed safety suite. Within that program, the lane change glitch took a higher priority than the slowdown routines – another flaw in the program – so they were all changing lanes when everyone else was slowing down. This led to additional collisions in lanes 1, 2, and 3, including fatalities.”

Chip asked, “So how can a lane change be more important than avoiding a crash with the car in front of you? That’s a pretty stupid way to prioritize things.”

Mercedes, again, agreed. “True. Thing was, Trafficnet (TM) wasn’t set up to deal with multiple vehicles suddenly going offline. They all just vanished, or so the program thought, and, instantly, they all thought they had a clear shot, going forward in lane 3. The vanishing of cars looks to have triggered a boundary overflow error – ah, um – a situation that it didn’t have a solid way of handling, like when a baby or a cat pounds on the keyboard.”

Everyone in the room had either children, cats, or both. Everyone in the room nodded solidly in agreement.

“So, with that error, it didn’t react properly. All of them didn’t react properly. Most cars were slowing correctly, Trafficnet (TM) cars were slamming into those at 75 miles per hour.” Mercedes advanced to the next slide that showed the massive number of collisions that began to happen within a few seconds of the Evolvo crash and subsequent blocking of lanes 1-3.

“Traffic in this part of 1110 usually has 1600 vehicles per hour per lane because we expect autonomous vehicles to drive more efficiently than human-piloted vehicles, and this part of 1110 is all-autonomous. So, every 2 and a quarter seconds, another vehicle advanced into the crash zone, slowing or changing lane – and causing another wreck – depending on whether or not it had Trafficnet (TM).”

Ray didn’t want to ask, but his office demanded that he did. “This explains most of the collisions in the first three lanes, I take it. What happened to jam up lanes 4 through 7?”

Mercedes advanced the slide.

Everyone winced when they saw the slide title: “LALOCA”, the acronym for Los Ancholess Locally-Operated Cab Authority. Everyone knew that LALOCA taxis had been involved, but this was the first they’d heard that they were the reason for closing down the other lanes. The LALOCA taxis were cheap cars with plastic interiors that were easily – and automatically – hosed down whenever a patron did something highly biological in one. No other cab company, traditional or app-driven, was allowed to operate in Los Ancholess because the city claimed that taxis were a utility that it had the right to regulate and own, 100%.

The fact that every LALOCA cab also provided location data on all its passengers and any face that its cameras picked up contributed to making the Los Ancholess police department one of the most effective in the nation. Sales tax subsidies kept the cabs affordable for one and all, making them quite popular all over town. But they were also supposed to have ironclad safety programming, no gimmicks. How was it that they had contributed to the pileup?

Mercedes revealed, “When LALOCA cabs are in maintenance mode and are heading back to their operations center, they don’t operate the same way as when they’re in dispatch mode.” Mercedes continued over the several low groans that had started. “They form a chain, as we know, and about 8 seconds after the initial collision, the Mimic had crossed over to the right-hand shoulder and a LALOCA chain of 17 cabs in lane 4 had slowed down to allow the Mimic to get over. This was normal behavior.

“However, one of the follow-on collisions from a Trafficnet (TM) vehicle in lane 3 spun out to the right and smashed into the lead LALOCA cab. This triggered the cabs’ self-preservation programming.”

Ray and Chip looked at each other while Summer asked, “Self-preservation? What, they have a survival instinct?”

Mercedes nodded. “Survival instinct is a good way to describe it. Anti-terrorism measure. They’re programmed to scatter if one of them is hit. Dispersion to minimize loss of life and property. The dispersion algorithms, however, are optimized for an urban setting, not an interstate. The LALOCA cabs interpreted the area to be one large plaza, and moved in random directions across it, mostly to the open lanes on the right. This meant that many drove directly into traffic, rear-ending vehicles that were slowing down or being struck by Trafficnet (TM) vehicles that were still moving at posted speeds.

“With collisions now having happened in all lanes, we entered the next phase of the accident, about 12 seconds after the initial collision.” The next slide’s title ominously read, “Collision Computation Overload”.

Mercedes held up her hands as she said, “For this one, I have to apologize in advance for getting technical, but there’s no other way to explain this. Basically, all vehicles keep a count of how many collisions are going on around them. While they can count an unlimited number of collisions, their programming gets overloaded if they have to deal with more than 15. There are the 15 that they keep in their calculations, but the rest are effectively ignored. And so, cars trying to maneuver around the 15 that they track wind up hitting one of the ones that they’re not tracking.

“This got worse, the more collisions that happened as a result of this programming limitation. 15 is the federally-mandated number that they need for compliance and because the navigation code is very difficult to write, it’s the standard that pretty much all manufacturers hold to. It’s sufficient for nearly every case, but in an exotic one such as this, it’s wholly inadequate.”

Ray was rubbing his temples. This was giving him a stress headache. “God, Mercedes, does this get any worse?”

Mercedes tilted her head in such a way as to indicate hope. “No. Well, there are additional collisions, eventually involving 197 vehicles over a total of 64 seconds from the initial collision. But, by that time, the city’s traffic thresholds had been exceeded for collisions in that area, and our central system began to override all vehicle programming in the area, diverting all traffic from entering the 1110, getting traffic to exit the 1110 if possible, and slowing down all cars uniformly to a full stop if they could not exit. The area of the first collision being at the far end of a major bridge, exit opportunities were severely limited, which explains the mile-and-a-half backup of traffic. Roughly 3400 cars, total, in the backup.”

Chip said, “So the ultimate culprit was the Evolvo. If it had been able to detect its brake failure, we would have had only a minor incident, if that.”

Mercedes shook her head. “I blame the Festivus. That debris was a large sheet of paper that it could have driven through or over, no problem. To the sensors on the Festivus, it looked like a huge brown wall that suddenly appeared in its lane. The AI didn’t know what to make of it, so it treated it as a major threat.”

Ray said, “Thank God neither one of you are blaming the LALOCAs. That’s a headache I don’t need.”

Summer said, “Or the school bus.”

Mercedes tilted her head in another way such as to indicate a lack of hope. “I wouldn’t draw either of those conclusions. The LALOCA programming made them such that they were entirely a hazard when encountering an issue while in maintenance mode on a freeway. They’re simply not safe, there. And the school bus is one reason our fatality and injury count is so high – it was moving at highway speeds with no safety restraints for the passengers – no seat belts, no airbags.”

Summer’s defensiveness was in full strength again. “Well, we tried to make seat belts mandatory before the bus would move, and there was always a kid that wouldn’t put one one or who’d take it off in the middle of a bus run. They brought the buses to a standstill!”

Chip demanded, “So why didn’t you punish those kids to get it to stop?”

Summer’s eyes flashed with cornered rage. “Like having a jail makes crime stop! You know the kind! They don’t care! They just want to watch the world burn!” Now her tone became supplicative. “And if we can’t require the kids to use them, they won’t. There’s no driver on board and encouragement programs had maybe 2% more usage than without those programs. And the buses are so much cheaper and easier to maintain without seatbelts!”

Ray held out his arms to quiet a potential shouting match between Chip and Summer. “All right! And I know I’m going to catch hell for allowing so many cars per hour but, realistically, Mercedes, what’s the number for driver cars at that speed?”

“1300 per lane per hour.”

“So that’s what percent of what we allow?”

Mercedes thought briefly, “13 times 6, about 80 percent.”

“So if we had all human drivers, we’d have 80 percent of the mess that we have, right?”

Mercedes’ face screwed up as she did some off-the-cuff statistical projections. “Wellllll… probably a lot less in this case, a sideswipe at speed that could make it off to the side. But a lot more, over time, in other driver error cases. With autonomous cars, we’re looking at far fewer of the one-off accidents and much lower total fatality and injury numbers, annually speaking, but we’ll see monsters like this every now and then because of the way different manufacturers emphasize safety or traffic considerations… how they all interlock and interoperate.”

Ray leaned back in his chair and looked at the ceiling. If only this wreck hadn’t happened a month before the election! But two flagship ideas of his, LALOCA and autonomous-only roads, had crashed and burned on the 1110. He was thinking fast…

“All right.” Ray sat back up in his chair. “Here’s our action items. The city of Los Ancholess needs to sue Trafficnet (TM), Evolvo, and the makers of the LALOCA cabs. We blame it all on them.”

Mercedes did a double-take. “Why not Fnord, as well? They’re ultimately the prime mover in this case.”

Ray held up a fist. “Three reasons. One.” Finger one went up. “We didn’t buy anything from them, so they can’t make a big settlement in our favor. Two.” Finger two went up. “They’re domestic, not like Evolvo from Sweden or wherever. Three.” Finger three went up. “They have a massive legal team and can drag a lawsuit out for decades. I need three big settlements before the people here vote. I gotta make lemonade out of these here lemons. Pick my battles carefully and all that. We play up the city traffic threshold system and talk about adjusting the numbers in favor of safety and how about also getting the cars per hour on the autonomous-only roads down to driven car rates?”

Mercedes didn’t follow. “That’s really not much benefit, going from 1600 to 1300 per lane per hour.”

Ray shook his head. “There’s a benefit, all right. A political benefit. We make this look good and we keep our jobs. All of us.” He looked right at Mercedes, who seemed to have the least political sophistication in the room.

At that moment, Mercedes was enlightened. “Our local system certainly put the damper on the havoc being raised by the Trafficnet (TM) problems and the collision count overload.”

Ray winked, knowingly. “End that sentence after ‘Trafficnet (TM) problems’, and you’ve got a keeper, there, kid.”