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Comment by nl | Hacker News Reader

I'm not sure if anyone else has realized it yet, but driverless cars will have to be taxed on a time-on-road basis, rather than at a flat rate.

The reason? The economics of electric cars and parking.

Initially it seems that they will fix the parking problem - driverless cars can be sent to park outside the CBD, reducing traffic and freeing up space.

But the problem is that people/software will optimize for price, and for electric cars the cheapest scenario is for them to be stuck in a traffic jam on a public road.

Instead of going to a parking bay, the software will route them to the nearest traffic jam, where the car can sit with the electric motors off for a large amount of time. Inevitably, some software will misjudge how long their charge will last, their batteries will run flat and the traffic jam will get worse.

As far as I can see the only way around this is to increase the cost of being on the road.

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Maybe not.

If you made it a flat fee, then it's kind of like runs-batted-in. The car has to get more people delivered to make money, so once it gets you to where you need to go as efficiently and quickly as possible, you get out and it speeds off to complete another fare.

Increasing road-cost would have the opposite effect, I think. If the cars make money just by being on the road and not by completing tasks, they lose the incentive to finish and jam-sitting becomes optimal.

Yes, I agree this could be an option.

But I'm not optimistic about the share-car thing, at least in cities without a strong existing public transport system. In most cities too many people travel at rush-hour, with unique route requirements (dropping kids at school etc).

Who exactly will do this? No major car company would risk their reputation selling a car with that programmed into its software.

Even if groups of hackers installed this on their cars, I can't imagine this movement gaining enough critical mass to honestly be a concern.

Who exactly will do this? No major car company would risk their reputation selling a car with that programmed into its software.

What's the risk, exactly?

Our car has an "ultra-economy mode" where the motor turns off when stationary - many cars already have this.

Our car can park itself - many cars already have this.

Our car will find a parking space, optimizing the route to and from the parking garage - that seems logical, why would a company not do that?

Our company will optimize the route to and from the parking garage, and the time spent in the garage vs on the road based on price vs economy of the car - why would a company not do that?

The problems only occurs when hundreds of cars independently make their own decision to drive as slowly as possible to and from the parking space.

(Edit: someone else pointed out that UPS routes their trucks to avoid left turns. This isn't too dissimilar to that - they do it to improve fuel economy, this would be done to improve costs too)

"Is GM causing massive gridlock to save Chevy owners a few pennies? Story at 11"

Bad press for all involved.

Fuel taxes already do this, while providing a strong incentive to run smaller and / or more efficient cars.

Roughly, 50% of my fuel bill is on direct taxation. That's it's primary tax cost, not the fixed annual license cost, and gives me a tax bill that's elastic by usage in exactly that way while also promoting efficiency.

Of course, best wishes to anyone trying persuade the average man in the street that this is A Good Thing....

You may have missed the bit about electric cars.

They can turn off their motors without losing any efficiency (which is why hybrids do so well on efficiency in city traffic). Depending on how slowly the traffic moves there will be a point where it is cheaper to stay in traffic (with the motor off x% of the time) compared to paying for parking.

Why the assumption that electricity for vehicular use will be taxed at the same rate as for domestic use when there's wide-scale adoption of electric cars? Red diesel, for agricultural use off-road, certainly isn't taxed at the same level as road use diesel in the UK.

Why are there going to be traffic jams? Computers are driving the cars. There's not going to be accidents anymore. There's not going to be that weird bottleneck effect where one sheepish person slows down to much and eventually everyone behind them stops.

There will still be traffic lights, bottlenecks, and for the foreseeable future there will still be conventional cars.

Driverless cars will still be limited by physics (their size and how fast they can accelerate). If car routing algorithms deliberately route cars to places where the traffic is slow (because they can loiter, saving on parking while using little power) then the traffic jams will be worse.

If we rebuilt the road system specifically for driverless cars maybe we could eliminate traffic jams. Otherwise...

In such a case, parking costs will reduce. Since the number of cars are expected to be lower if they are driverless, the amount of space required for parking will be less. It would also mean that expenditure on the prime real estate required would be less (marginal costs are higher, marginal decrease would hence be more benefitial) and that will result in cheaper parking.

Secondly, it also opens up the scope for private taxies. A person can allow his car to be utilized by a certain section of his peers - colleagues, neighbours etc for low prices - resulting in lower parking time.

It'd also be possible to double-park (triple, or more even), using less parking space. If the car in the middle needs to get out it can ask its neighbours (several levels deep) to shuffle around and make a path

Loitering can be easily avoided by taxing the time on public roads, possibly taxing more for the time the cars are empty and stay on public roads.

That was exactly my point.

Traffic lights have no purpose except for conventional cars. Driverless cars can just go through intersections whenever no vehicle needs to go through perpendicularly. All intersections would just work like four-way stops, minus the requirement to stop when not yielding to another vehicle, and with more batching and parallelism for efficiency rather than strict serialization.

Traffic lights have no purpose except for conventional cars.

Yes, and for the forseeable future there will be conventional cars, as well as bicycles and pedestrians.

What does CBD stand for?

Central Business District

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