How about a device that pedestrians could optionally carry that would broadcast their presence to all vehicles
Six cars aced new pedestrian detection tests
61–70 of 73 posts
Re: Six cars aced new pedestrian detection tests
#62Virtually eliminating pedestrian fatalities could be quite simple, but we don't do it because it would inconvenience people: Set a 30 km/h (18 mph) speed limit everywhere but controlled-access freeways, and enforce it strictly. At 30km/h a car-pedestrian collision is almost always non-fatal[1], and at that speed cars can stop almost instantaneously. 1: https://nacto.org/docs/usdg/relationship_between_speed_risk_...
That means halving the bandwidth of all inner-city roads (that are traditionally at 35mph+) If a road used to carry 1000-cars per hour, it will only carry 500-cars per hour if you drop the speed limit from 35 -> 18. Effectively doubling the length of time for congestion. You can get around this by building twice as many roads I guess, but cities don't really have any more room.
If there are 2 seconds of distance between cars at 36mph and 2 seconds of distance between cars at 18mph then the road has exactly the same capacity at both speeds.
Also, the constraint on street capacity is intersections in the vast majority of cases. Until you remove intersections nothing else really else matters.
Re: Six cars aced new pedestrian detection tests
#63Earlier quoted context omitted.
That means halving the bandwidth of all inner-city roads (that are traditionally at 35mph+) If a road used to carry 1000-cars per hour, it will only carry 500-cars per hour if you drop the speed limit from 35 -> 18. Effectively doubling the length of time for congestion. You can get around this by building twice as many roads I guess, but cities don't really have any more room.
If there are 2 seconds of distance between cars at 36mph and 2 seconds of distance between cars at 18mph then the road has exactly the same capacity at both speeds. Also, the constraint on street capacity is intersections in the vast majority of cases. Until you remove intersections nothing else really else matters.
I don't think people are "timing" their cars, and are instead driving at "car-lengths" worth of distance between the person in front of them
If you instead assume 1-car lengths worth of distance at both 36mph and 18mph, the road capacity shrinks dramatically between the two speeds.
Re: Six cars aced new pedestrian detection tests
#64Virtually eliminating pedestrian fatalities could be quite simple, but we don't do it because it would inconvenience people: Set a 30 km/h (18 mph) speed limit everywhere but controlled-access freeways, and enforce it strictly. At 30km/h a car-pedestrian collision is almost always non-fatal[1], and at that speed cars can stop almost instantaneously. 1: https://nacto.org/docs/usdg/relationship_between_speed_risk_...
artificially setting limits like that is a poor solution, especially when you're depending on police enforcement to ensure compliance.
a better solution is narrowing lanes (to 9-10 ft), and possibly installing bollards everywhere, because that internalizes the costs of collision (car gets wrecked and you get hurt in addition to pedestrians), so drivers naturally self-regulate driving behavior for safety (rather than the secondary measure, speed). you also don't need an external police force and it's attendant costs, both financially and societally, for enforcement.
Re: Six cars aced new pedestrian detection tests
#65This is funny, because as I recall only weeks ago AAA had lackluster reviews about these same features, likely with the same cars. Consumer Reports seems neutral, which is to say having the feature is probably better than no feature but not a silver bullet.
https://www.consumerreports.org/car-safety/pedestrian-detect...
https://www.consumerreports.org/car-safety/cars-make-progres...
Re: Six cars aced new pedestrian detection tests
#66I have to turn the pedestrian detection off every time I drive past the local school. Why? The kids figured out that it's really easy to make new cars emergency brake by just pretending to walk onto the road. People suck.
Beginning of pranks to come with self drive cars. Imagine when someone realised you can slam on the brakes in front of X brand of car and it prioritises avoiding the car in front over all else
Hopefully the expensive self driving car can afford to integrate a $40 dashcam.
Re: Six cars aced new pedestrian detection tests
#67Earlier quoted context omitted.
That means halving the bandwidth of all inner-city roads (that are traditionally at 35mph+) If a road used to carry 1000-cars per hour, it will only carry 500-cars per hour if you drop the speed limit from 35 -> 18. Effectively doubling the length of time for congestion. You can get around this by building twice as many roads I guess, but cities don't really have any more room.
If there are 2 seconds of distance between cars at 36mph and 2 seconds of distance between cars at 18mph then the road has exactly the same capacity at both speeds. Also, the constraint on street capacity is intersections in the vast majority of cases. Until you remove intersections nothing else really else matters.
You're also underselling the intersections part, because getting traffic to intermix at intersections is incredibly easy at 20mph. And, what you've conceptually stated (no loss in capacity) has been empirically demonstrated.
Finally, you get vastly different places at 40 mph vs 20mph. At 20, roads are smaller, people can safely exist close to the roadway and even enjoy themselves, and you don't need huge buffer zones for the safety of drivers or people. All these things compound to put people (willingly) in closer proximity to one another, so that, while peak travel speed is lower, traffic throughput stays relatively consistent, and travel times decrease overall because many long trips get replaced with short ones.
Re: Six cars aced new pedestrian detection tests
#68Earlier quoted context omitted.
If there are 2 seconds of distance between cars at 36mph and 2 seconds of distance between cars at 18mph then the road has exactly the same capacity at both speeds. Also, the constraint on street capacity is intersections in the vast majority of cases. Until you remove intersections nothing else really else matters.
I don't think people are "timing" their cars, and are instead driving at "car-lengths" worth of distance between the person in front of them If you instead assume 1-car lengths worth of distance at both 36mph and 18mph, the road capacity shrinks dramatically between the two speeds.
If that is true, most congestion on my way to work is after an accident. Not having that accident at 30kph is much more likely than not having it at twice the speed, giving the same distance to react and brake.
Re: Six cars aced new pedestrian detection tests
#69I’m a fan of Tesla but when you see that their system is not a bit better than the competition (they’re all failing in low light conditions), I don’t know how they can claim autonomous driving “coming soon.” Especially after Uber’s death you’d think that this specific condition would be given extremely high priority.
Having actually test-driven many of these cars this year, in practice Tesla is much better than the competition. There might still be problems in different conditions, and it is not fully autonomous of course, but the common HN myth that other cars basically have the same lane assist that tesla has is just a lore. Tesla autopilot is light years ahead of the rest of them.
Look at the IIHS ratings though. The Tesla failed to detect a crossing child in both the 12 and 25mph tests. In both, it still hit the child with only a 5mph speed reduction.
Seems unlike Tesla to be out-classed like this. Six other models had significantly better speed reduction or didn't hit the pedestrian at all.
https://www.iihs.org/news/detail/performance-of-pedestrian-c...
Re: Six cars aced new pedestrian detection tests
#70Earlier quoted context omitted.
Having actually test-driven many of these cars this year, in practice Tesla is much better than the competition. There might still be problems in different conditions, and it is not fully autonomous of course, but the common HN myth that other cars basically have the same lane assist that tesla has is just a lore. Tesla autopilot is light years ahead of the rest of them.
Look at the IIHS ratings though. The Tesla failed to detect a crossing child in both the 12 and 25mph tests. In both, it still hit the child with only a 5mph speed reduction. Seems unlike Tesla to be out-classed like this. Six other models had significantly better speed reduction or didn't hit the pedestrian at all. https://www.iihs.org/news/detail/performance-of-pedestrian-c...
This is definitely interesting, and it is completely possible that in some situations other manufacturers might have the upper hand.
They did test it on autopilot though, right? It says "standard" on Model 3. AFAIK autopilot features are not standard, it's an option you have to buy on Tesla. I also can't find anywhere in the report whether the car was actually driving on autopilot or not. All of these details I think make a big difference. A standard non-autopilot-equipped model 3 might just be subpar to other cars, it would not surprise me.