There are two different visions of the future of self-driving cars. Both visions agree that a smart car needs to process a massive amount of information in order to make real-time decisions.

One vision is that smart cars will be really smart and will include a lot of edge computing power and AI that will enable a car to make local decisions as the car navigates through traffic. Cars will likely to able to communicate with neighboring cars to coordinate vehicle spacing and stopping during emergencies. This vision requires only minimal demands for external broadband, except for perhaps to periodically update maps and to communicate with things like smart traffic lights.

The other vision of the future is that smart cars will beam massive amounts of data to and from the cloud that includes LiDAR imagery and GPS location information. Big data centers will then coordinate between vehicles. This second vision would require a massively robust broadband network everywhere.

I am surprised by the number of people who foresee the second version, with massive amounts of data transferred to and from the cloud. Here are just some of the reasons why this scenario is hard to imagine coming to fruition:

• Volume of Data. The amount of data that would need to be transferred to the cloud is massive. It’s not hard to foresee a car needing to transmit terabytes of data during a trip if all of the decisions are made are made in a data center. Most prognosticators predict 5G as the technology that would support this network. One thing that seems to be ignored in these predictions is that almost no part of our current broadband infrastructure is able to handle this kind of data flow. We wouldn’t only need a massive 5G deployment, but almost every part of the existing fiber backbone network, down to the local level, would need to also be upgraded. It’s easy to fall into the trap that fiber can handle massive amounts of data, but the current electronics are not sized for this kind of data volumes.
• Latency. Self-driving cars need to make instantaneous decisions and any delays of data going to and from the cloud will add delays. It’s hard to imagine any external network that can be as fast as a smart car making its own local driving decisions.
• Migration Path. Even if the cloud is the ultimate network design, how do you get from here to there? We already have smart cars and they make decisions on-board. As that technology improves it doesn’t make sense that we would still pursue a cloud-based solution unless that solution is superior enough to justify the cost of migrating to the cloud.
• Who will Build? Who is going to pay for the needed infrastructure? This means a 5G network built along every road. It means fiber built everywhere to support that network, including a massive beefing up of bandwidth on all existing fiber networks? Even the biggest ISPs don’t have both the financial wherewithal and the desire to tackle this kind of investment.
• Who will Pay? And how is this going to get paid for? It’s easy to understand why cellular companies tout this vision as the future since they would be the obvious beneficiary of the revenues from such a network. But is the average family going to be willing to tack on an expensive broadband subscription for every car in the family? And does this mean that those who can’t afford a smart-car broadband connection won’t be able to drive? That’s a whole new definition of a digital divide.
• Outages. We are never going to have a network that is redundant down to the street level. So what happens to traffic during inevitable fiber cuts or electronics failures?
• Security. It seems sending live traffic data to the cloud creates the most opportunity for hacking to create chaos. The difficulty of hacking a self-contained smart car makes on-board computing sound far safer.
• Who Runs the Smart-car Function? What companies actually manage this monstrous network? I’m not very enthused about the idea of having car companies operate the IT functions in a smart-car network. But this sounds like such a lucrative function I can’t foresee them handing this off to somebody else? There are also likely to be many network players involved and getting them all to perfectly coordinate sounds like a massively complex task.
• What About Rural America? Already today we can’t figure out how to finance broadband in rural America. Getting broadband along every rural road is going to be equally as expensive as getting it to rural homes. Does this imply a smart-car network that only works in urban areas?

I fully understand why some in the industry are pushing this vision. This makes a lot of money for the wireless carriers and the vendors who support them. But the above list of concerns make it hard for me to picture the cloud vision. Doing this with on-board computers costs only a fraction of the cost of the big-network solution, and my gut says that dollars will drive the decision.

It’s also worth noting that we already have a similar example of this same kind of decision. The whole smart-city effort is now migrating to smart edge devices rather than exchanging massive data with the cloud. As an example, the latest technology for smart traffic control places smart processors at each intersection rather than sending full-time video to the cloud for processing. The electronics at a smart intersection will only communicate with the hub when it has something to report, like an accident or a car that has run a red light. That requires far less data, meaning far less demand for broadband than sending everything to the cloud. It’s hard to think that smart-cars – which will be the biggest source of raw data yet imagined – would not follow this same trend towards smart edge devices.