Automakers are pushing hard toward the goal of putting self-driving vehicles on public roads. The technology building blocks to do that keep popping up on vehicles for sale.
Cars already can warn drivers of obstacles, impending collisions and lane departures. Some nudge cars back into lanes or even stop them. But a lack of infrastructure may slow the rise of autonomous cars as it has the growth of electric vehicles. Practical EVs are available, but sales have lagged because public recharging stations are scarce.
Autonomous vehicles will have to be connected to an external system that feeds them information about other vehicles, traffic conditions and road work. And providing the stream of information -- complete, accurate and universal -- for self-driving vehicles may be even harder.
That's because, unlike devices to recharge EVs or assist human drivers, the infrastructure for autonomous vehicles must ensure passenger safety.
Auto designers and engineers understand the challenges of developing safe vehicles. They have extensive validation procedures in place to verify any technology before it is put on the market. The problem with going from assisting drivers to replacing them in autonomous vehicles is that manufacturers must rely on outsiders to build the enabling infrastructure.
And public road funding is plenty stressed already. This would add a substantial and entirely new level of public financing. It's unrealistic to expect that every hard-pressed state and local government will reallocate resources to create infrastructure that, at least early on, would mostly benefit a small number of well-heeled motorists. So autonomous vehicles may be further off than sometimes predicted.
But the technology need not be wasted. Automakers are adding driver-assistance features that make operating a vehicle easier and safer. And those features can continue to be marketed profitably until self-driving cars become practical.