Comment by stkdump | Hacker News Reader

Comment by stkdump | Hacker News Reader

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Arguments I heard that make no sense to me:

- Autonomous cars will improve traffic because stopped cars can start going at the same time at an intersection -> Then you have no safety distance. And while theoretical improved reaction times mean you might need a bit less distance, the quadratic term comes from the needed breaking deceleration, not the reaction time.

- Autonomous cars will reduce congestion: they can't if they are supposed to drive around empty either to park somewhere else or to get to the next person to transport. On the contrary, they will increase congestion.

Note also that I don't buy the "work" inside "very small cars". It's not just that having to drive prevents you from working. Also the overall comfort while traveling isn't good enough outside of trains or planes for anything but some tiny amount of work.

I am on board with the benefits for old, disabled, tired and drunk people though. Also, I do accept that they will prevent a lot of accidents and deaths.

You only need reaction time factored in when the driver in front might act unpredictably. If the self driving cars pass information about the road ahead to cars behind, and let the car behind know what they are doing and planning to do the the required 'reaction time' is zero. Congestion is often caused by reaction times stacking up until a car has to completely stop. Then you have a stationary section of road that makes all the other cars that encounter it stop. If reaction time is zero, this removes that congestion, so more cars can drive on a section of road and not clog it. The same applies to intersections, roundabouts, on and off ramps on motorways. Just the simple act of negotiating with the cars around eliminates all of it.

Just think a little about what having a computer control the car would really mean, rather than thinking of them like robot people.

An autonomous car in front of me can still act in a way that I or my car can't predict, as long as we haven't eliminated humans and animals completely from being anywhere near roads.

> - Autonomous cars will improve traffic because stopped cars can start going at the same time at an intersection -> Then you have no safety distance. And while theoretical improved reaction times mean you might need a bit less distance, the quadratic term comes from the needed breaking deceleration, not the reaction time.

This is more about it deleting the human not paying attention + reaction time to next bumper.

Currently it looks like

1. Light goes red

2. Car1 reaction time and then moves

3. Car2 swipes off TikTok app + reaction time off car1's brake lights

4. Car3 swipes off Instagram + reaction time off car2's brake lights

5. Car4 Yelling at kids in back seat until they hear Car5's horn + reaction time

Versus autocars

1. Light goes green

2. Cars 1-N all release their brake faster than human reaction time and begin moving ever so slowly. Their acceleration rates are respectively less for the reasons you said. More cars make it through the light meaning less likely to accumulate and create multilight jams.

Autonomous cars driving around empty is a good argument for them being on a public rideshare network. They are more likely to pickup a passenger along the way to their actual destination. Even if the route is non-direct, any trip that gets them closer to home is not wasted travel because that person(s) wanted to travel regardless. Similarly when they go to pick you up.

IMO The bigger culprit here is the artificial need for people to work in an office, and for them to start at the same time. Work from home and higher agency over time would mean people do novel things like 1) Not commute at all or, like I do, 2) Take a couple meetings from home and commute when it's quiet.

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