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Prius Sets ‘Autonomous’ Cannonball Run Record With AI Driving Assistant

A Cannonball run usually involves triple-digit speeds, but the most recent record setting run didn't. A new benchmark for autonomous driving has been set for both the Cannonball and Spanish Trail.

Autonomous Cannonball Run Record(Photo/Jay Roberts)
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The Autonomous — now referred to as the Semi-Autonomous — Cannonball record has been broken. A Spanish Trail Semi-Autonomous record was also established. Both were done in a Toyota Prius, of all things!

  • New Semi-Autonomous Cannonball Run Record of 43 hours and 18 minutes, at 98.4% autonomous
  • Established Spanish Trail Semi-Autonomous Record at 32 hours and 56 minutes, at 97.432% autonomous

These transcontinental records were set by Jay Roberts and his partners in a 2017 Prius with a Comma.ai driver assistance system.

Roberts has become a staple member of the Fraternity of Lunatics that makes up the Cannonball community. He started his Cannonball journey with a run in the 2021 Musketball — a sub-100-horsepower timed cross-country drive event.

He then set the non-stop Cannonball Run record — at 33 hours, 45 minutes — in September 2022. Roberts completed a Spanish Trail nonstop run on his return to the East Coast, where he lives, but wasn’t able to set a new record.

Roberts’ third Cannonball Run was just run from April 11 to 13, 2024. He was out to break the 8-year-old Autonomous Cannonball Run record held by Alex Roy in a Tesla Model S, and succeeded. All of these runs were done in Roberts’ 2017 Toyota Prius.

Autonomous Cannonball Run Record History

Roberts, Roy, and others in the Cannonball community have decided to change the name of the record from “autonomous” to “semi-autonomous.” This is because a human is still needed in the vehicle to set the record with current technology.

The semi-autonomous Cannonball record began in 2015 when a Delphi self-driving car went coast to coast from San Francisco to New York over the span of 9 days.

Later that year, Carl Reese and Deena Mastracci set the EV and Semi-Autonomous Cannonball record. The record was set at 57 hours and 48 minutes in a Tesla Model S P85D.

On August 24, 2016, Alex Roy, Warren Ahner, and Franz Aliquio set a new bar for both Semi-Autonomous and EV Cannonball runs. The new records were established in a 2016 Tesla Model S P90D at 55 hours flat.

The team claimed a 97.7% autonomous number, but that was found to just be an estimate. Roy told Roberts that it “was estimated and it could be as high as 98% or as low as 96%. There was no verifiable method to get an actual number.” Since then, the EV record has been lowered to 42:17, but no one has challenged the autonomous record.

Co-Driver Conundrum

Autonomous Cannonball Run Record
Jay and Gypsy Roberts; (photo/Jay Roberts)

In October 2023, at a celebration honoring Brock Yates, Roberts spoke to Roy, the autonomous Cannonball record holder, about his plans to break the record. After explaining his plans, Roy asked Roberts if he “needed a co-driver.” After further discussion, that co-drive offer would likely also come with some media attention, including a journalist in the back seat for the run.

Roberts’ first choice for his co-driver was a good friend with whom he’d been discussing the run for a few years. Sadly, that friend couldn’t do the run on Roberts’ scheduled run date.

For years he’d also been joking with his wife about joining him on a Cannonball run. She always laughed at him and said no, as she’s a rule follower and would be uncomfortable driving at the usual Cannonball speeds.

But Roberts’ planned run would not be like a typical Cannonball. The driver assistance system that was going to be used for the autonomous run has a maximum cruise control setting of 90 mph.

After careful consideration, Gypsy Roberts agreed to support her husband. Roberts chose his wife because they had traveled the world together for nearly 30 years and knew each other’s quirks and habits. He says she “was clearly the best choice.”

That’s right — Roberts turned down legendary Cannonballer and autonomous record holder Alex Roy, whom he considers the “godfather of modern-day Cannonball.” Roberts says it was the hardest “no” he says he’s ever had to give anyone.

Creating a Self-Driving Prius

When I heard about this record, the first thing that crossed my mind was that the Prius does not offer “self-driving” tech. While that is correct, Roberts was able to give it this capability by adding an aftermarket system called Comma 3X.

This $1,450 gadget can turn just about any vehicle already equipped with an OBDII port, self-lane centering/lane keep assist, and adaptive cruise control into a “self-driving” vehicle. The device runs on an open software system called OpenPilot, and while it can be upgraded with a subscription, which offers video and data backups to the cloud, it does not require it to work.

Comma.ai Driver Assistance

Autonomous Cannonball Run Record
Comma 3X driver-assistance system; (photo/Jay Roberts)

Roberts says the Comma 3X system took him about 10 minutes to install in his 2017 Prius and worked impressively well from the start. It does have some interesting quirks, however, and one big limiting factor for Cannonballing. The OpenPilot software allows a maximum speed setting of 90 mph.

The Comma.ai system offers hands-free driving on any roadway but doesn’t recognize stop lights or stop signs. So, the driver behind the wheel still needs to take care of those situations manually. A driver-facing camera on the system ensures the driver is paying attention and alerts them if they aren’t.

In order to change lanes using the system, you use the turn signal and give the steering wheel a light bump in the direction you want to go. It will then change lanes, but it isn’t smart enough to check the lane for traffic, so the driver still must pay attention and make decisions.

Measuring Autonomy

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

Roberts felt the burden of proof was the biggest obstacle to overcome to do a semi-autonomous Cannonball run correctly. He wasn’t content with just an estimate and wanted verifiable numbers.

After talking with software developers for OpenPilot, it was made clear to Roberts that they had no interest in writing code to determine the percentage of hands-free driving for every drive logged into the system. They didn’t see the value in it and kept asking his reasons for needing it. Of course, he didn’t exactly want to disclose that part before his run.

Because the software couldn’t be used to determine how autonomous the run was, Roberts devised his own crude and relatively simple solution.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

The steering wheel was wrapped in electrically conductive tape. Two digital displays on the dash were wired to the steering wheel. One was a counter that totaled the number of times the wheel was touched, and the other was an accumulative timer. The driver wore a mesh jacket that had electrically conductive gloves attached. The jacket was wired to a 12V power supply.

When the driver touched the steering wheel, an electrical circuit was completed. The system recorded the total time the driver’s hands were on the wheel and the number of times it was touched.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

Semi-Autonomous Record Run

For the semi-autonomous Cannonball run on April 11-13, 2024, Jay and Gypsy swapped “driving” duties every 2.5 to 3 hours during the run. They would set the Comma.ai system to 5-10 mph over the speed limit, both to be safe and to avoid attracting law enforcement.

The focus of this coast-to-coast run was to touch the steering wheel as little as possible versus worrying about the overall time.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

They logged the numbers from the dash displays every hour on the entire run to keep accurate data. The Roberts had a pretty clean run, besides a 2-hour delay in Texas due to a jack-knifed big rig. The first hour of that, they only drove a single mile, and the next, they managed just 7 miles.

Roberts said, “Again, the Cannonball curse of things one can’t control reared its head. One can solve 500 problems before leaving the starting point and think everything is perfect, but a single problem on the road can lower the times by hours.”

Over the 2,865-mile coast-to-coast Cannonball run, the duo made six stops for gas and seven for the restroom. They were still able to maintain an average speed of 67 mph.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

The total time Roberts touched the steering wheel over the 43-hour and 18-minute adventure was just 39 minutes and 21 seconds. This set the new semi-autonomous Cannonball run record, beating the previous record by nearly 12 hours and raising the bar with a verifiable 98.416% hands-free run.

Same-Day Cannonball Truck Record Attempt

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

On the same day the Roberts left New York City, another team was there planning to make an attempt at the Cannonball truck record. This notable record has stood since 1979, set by Dennis “Mad Dog” Menesini in a 1979 GMC Dually.

That run was later made famous in the Cannonball Run movie. Roberts, a historian of sorts on all things Cannonball, notes, “Yes, Dennis actually did drive through the fence at the Goodwives shopping center in Darien, Connecticut, to make a shortcut to Interstate 95.”

The Cannonball truck record is one of the very few left to be broken that was set during the 1970s original runs. On this April 2024 day, a three-person team set out in a Ford Maverick hybrid, 8 hours after Roberts.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

As with many who have tried before them, the team experienced the “Cannonball curse.” A 2-hour highway delay in Pennsylvania derailed this truck’s Cannonball record attempt. The team still managed a 36-hour 44-minute Cannonball run, however.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

They were assisted by two 32-gallon fuel tanks in the bed of the truck, which they borrowed from Roberts, who had used them on his nonstop record and would use them again a few days later.

Roberts Had to Drive Home, So …

Autonomous Cannonball Run Record
Mason Dibley behind the wheel of the semi-autonomous Prius; (photo/Jay Roberts)

Roberts had to return to his home in North Carolina after his record run, so he figured he might as well try to set a new nonstop Spanish Trail record and establish a semi-autonomous one.

The Spanish Trail is the Cannonball’s less famous sibling. It’s a cross-country trip between Dog Beach in San Diego and Jax Beach in Jacksonville, Fla. This is the shortest driving distance between the Atlantic and Pacific oceans.

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

After a few days’ rest, Roberts’ wife flew home, and his friend Mason Dibley joined him. The duo installed the two 32-gallon fuel tanks in the Prius and made their way to San Diego.

Spanish Trail Autonomous Record Established

The next morning, at sunrise, they left Dog Beach with a total fuel load of 60 gallons and set out for Florida. The duo’s goal was to make the Spanish Trail run with zero fuel stops and establish a semi-autonomous percentage of greater than 97%.

Impressively, after 2,363 miles of nonstop travel, at an average speed of 72 mph, they met both of their goals. It took them 32 hours and 56 minutes to cross the continent, with 97.432% of it being semi-autonomous.

They did not, however, break the nonstop record, which stands at 27 hours and 13 minutes, set by Steve Brown in a 2014 GMC truck from March 20 to 21, 2020.

Autonomous Cannonball Run Record
Mason Dibley and Jay Roberts on Jax Beach, FL, at the end of their Spanish Trail run; (photo/Jay Roberts)

The only real issue they had on the run was a headlight malfunction. In the end, after some deep Google searches, they cleaned the bumper sensors at a gas station and then cycled the key to reset the system, and it worked. The bugs and dirt in the sensors had thrown the error code and turned off the lights.

For reference, “nonstop” in the Cannoball community means no fuel stops. It does not mean the vehicle didn’t stop along the route for other reasons, like the bathroom, driver changes, food, bug removal from sensors, etc.

April 2024 Cannonball Records

Autonomous Cannonball Run Record
(Photo/Jay Roberts)

Not only did both of Roberts’ cross-continental drives establish new autonomous Cannonball records, but all three of these April 2024, runs also kept the Cannonball’s 53-year safety record intact.

Maybe the coolest part of this entire story is that Gypsy Roberts is now in the Cannonball history books and the only female to hold a current record.

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