5 ms·

I don't see why you need special cases in the code. Sat nav units have had speed limits built in for years. Why not just look it up in a database? (the car know

by joshvm 7y ago

I don't see why you need special cases in the code. Sat nav units have had speed limits built in for years. Why not just look it up in a database? (the car knows where it is after all, and requiring a GPS fix could be mandatory - most drones won't arm without it, for example)

dmitrygr 7y ago
Because those databases are out of date approximately 100% of the time... Road construction, for example is a reason why
- joshvm 7y ago
  However if the sat nav gives you a prior that says 35 mph, and the road sign says 85 mph, do you trust it? Especially if the adjacent roads are also low speed, and it's clearly not a highway etc. This is perhaps a bad example as there are plenty of roads in the UK that transition from national to 30 in rural areas (and plenty of hamlets that you can bomb through). Roadworks are an obvious situation where you drive at a _lower_ speed. This would be a case where you could use computer vision to identity an obstruction, identify roadworks and then adjust speed. Those databases shouldn't be out of date. Most highway agencies (UK for sure) publish planned works and improvements weeks in advance. Google and Apple both show road closures for example. I belive speed changes are similar.
  - dmitrygr 7y ago
    Google maps keep saying 101N in San carlos is 65mph. It's been 55mph due to construction for 5 months... This is literally Google's back yard
    - t-writescode 7y ago
      65 in a 55 is much less dangerous than 85 in a 35. It wouldn’t be common that road conditions would permit very high speeds while at the same time having an artificially lowered speed limit (e.g construction). This shouldn’t be a problem, in general, with a couple extra sanity checks. I would expect the correct solution to more commonly have the opposite problem: too slow in a faster zone.
    - asterisk_ 7y ago
      Even so, what's the worst-case scenario in biasing towards lower speed and assisting your vision system with a knowledge base? You perform the task of vision 100% of the time driving. From a purely probabilistic standpoint, even assuming highly accurate ML, the relatively infrequent database updates still make for a sensible prior. This is somewhat adjacent to what Gary Marcus has been arguing, and I think it makes a lot of sense; there seems to be no compelling reason to rely exclusively on primitives (i.e. vision) when good priors are easily accessible.
- kelnos 7y ago
  Out of date is probably not that big a deal. If a speed limit is lowered from 40 to 35, or even 65 to 55, and the database doesn't get updated, it's unlikely to create a dangerous situation if a car doesn't know about it. But a car thinking a 35mph zone is an 85mph zone... that could be a very big deal indeed. Regardless, if self-driving cars (or at least "computer assisted driving" cars) were to be widely deployed enough and shown to depend on these sorts of databases, I'd expect it to become a legal requirement to make sure these databases are kept up to date by city/county/state agencies, and that car systems get those updates. Otherwise, expensive liability ensues.
  - lostlogin 7y ago
    It gets complicated fast. Currently if there is some sort of emergency or requirement to notify road users of a change to driving conditions, a person can just put a sign up. It mostly just works. If road workers are also required to update a database that needs to be read by a car, that’s a lot of infrastructure that needs to be working. You also need to have the humans and machines reading the signs as the same at every time point, as “road closed” or “one way” needs to be correctly understood by everyone at the same time. In an emergency that may involve bad weather or some other sort of disaster, a remote database is not going to work very well. The car needs to read the actual sign properly.
melling 7y ago
Waze knows the speed limit and warns you when you exceed it.
- Piskvorrr 7y ago
  Except when it "knows" wrong, or the limit is conditional (days, hours, vehicle classes), etc.
rypskar 7y ago
How much can you trust that data? My car tell me what the speed limit is by using a database and reading signs. On my commute to work there is a part where it tell me the speed limit is 5km/h when it actually is 80km/h and another place where it for a short bit shows the limit as 80km/h where the correct is 30km/h
- leokennis 7y ago
  In The Netherlansds (and probably other places), many roads have a different maximum speed between 07:00-19:00 and 19:00-07:00.
  - t0mas88 7y ago
    Both Netherlands and Germany have these time based speeds on a lot of highways where the special case is in text underneath the sign. BMW handles it if the navigation database is up to date. At least on the A2 in the Netherlands, which has the 06:00 to 19:00 changes between 100 and 130. It also understands temporary changes for roadworks, but gets it wrong when a roadwork/temporary sign has an exception like "when road is wet" That tells me the camera only understands the main sign and then the navigation database tells it about exceptions / special cases. Nice as a small reminder on your screen, but I wouldn't trust it to self drive based on that data.
- joshvm 7y ago
  Neither is ideal. But you should use what information you have. There is still no excuse for making a decision like 85 in a 35. Worst case this should be a disengage or the car could defer to you - eg visual warning on the dash "speed limit unclear, override?" In the UK smart motorways can vary from 30mph to 70mph according to traffic. This can change within minutes and obviously cannot be in databases. So this is a good case for sign recognition. In theory though, there is some network that's updating the speed limits and there's no technical reason why that couldn't be a public information service (maybe it already is). Then you have the sibling comments - speed limits which are time based. I would imagine this is country specific and is, mostly, a matter of public record. But would you trust CV to recognise text on a sign with specific hours? I don't know how complex the signage is, but trying to use ML for this seems absurdly wasteful of resources. Finally you have other information - how fast are the cars around you travelling? Have you detected an obstruction on the road (eg cones)? Is the weather inclement and therefore you should drive more slowly, etc. I would imaging that if self driving cars become ubiquitous there will eventually be a system for real time speed limit determination, whether that's some kind of wireless beacon at regular intervals or an online database that's kept up to date I don't know.
Robotbeat 7y ago
Tesla already looks it up in a database. Current Teslas CANNOT have this error simply because MobilEye patented reading speed limit signs and Tesla no longer uses the MobilEye system and haven't since mid-2016.
- bsaul 7y ago
  side remark : how can you patent a "function" ? Wouldn't mobileeye have to patent a certain way of reading speed limit ?
  - brian_herman__ 7y ago
    It is called a process patent.
    - iqtidar 7y ago
      Thanks for the enlightenment!

by joshvm 7y ago

dmitrygr 7y ago

Because those databases are out of date approximately 100% of the time... Road construction, for example is a reason why

joshvm 7y ago
However if the sat nav gives you a prior that says 35 mph, and the road sign says 85 mph, do you trust it? Especially if the adjacent roads are also low speed, and it's clearly not a highway etc. This is perhaps a bad example as there are plenty of roads in the UK that transition from national to 30 in rural areas (and plenty of hamlets that you can bomb through). Roadworks are an obvious situation where you drive at a _lower_ speed. This would be a case where you could use computer vision to identity an obstruction, identify roadworks and then adjust speed. Those databases shouldn't be out of date. Most highway agencies (UK for sure) publish planned works and improvements weeks in advance. Google and Apple both show road closures for example. I belive speed changes are similar.
- dmitrygr 7y ago
  Google maps keep saying 101N in San carlos is 65mph. It's been 55mph due to construction for 5 months... This is literally Google's back yard
  - t-writescode 7y ago
    65 in a 55 is much less dangerous than 85 in a 35. It wouldn’t be common that road conditions would permit very high speeds while at the same time having an artificially lowered speed limit (e.g construction). This shouldn’t be a problem, in general, with a couple extra sanity checks. I would expect the correct solution to more commonly have the opposite problem: too slow in a faster zone.
  - asterisk_ 7y ago
    Even so, what's the worst-case scenario in biasing towards lower speed and assisting your vision system with a knowledge base? You perform the task of vision 100% of the time driving. From a purely probabilistic standpoint, even assuming highly accurate ML, the relatively infrequent database updates still make for a sensible prior. This is somewhat adjacent to what Gary Marcus has been arguing, and I think it makes a lot of sense; there seems to be no compelling reason to rely exclusively on primitives (i.e. vision) when good priors are easily accessible.
kelnos 7y ago
Out of date is probably not that big a deal. If a speed limit is lowered from 40 to 35, or even 65 to 55, and the database doesn't get updated, it's unlikely to create a dangerous situation if a car doesn't know about it. But a car thinking a 35mph zone is an 85mph zone... that could be a very big deal indeed. Regardless, if self-driving cars (or at least "computer assisted driving" cars) were to be widely deployed enough and shown to depend on these sorts of databases, I'd expect it to become a legal requirement to make sure these databases are kept up to date by city/county/state agencies, and that car systems get those updates. Otherwise, expensive liability ensues.
- lostlogin 7y ago
  It gets complicated fast. Currently if there is some sort of emergency or requirement to notify road users of a change to driving conditions, a person can just put a sign up. It mostly just works. If road workers are also required to update a database that needs to be read by a car, that’s a lot of infrastructure that needs to be working. You also need to have the humans and machines reading the signs as the same at every time point, as “road closed” or “one way” needs to be correctly understood by everyone at the same time. In an emergency that may involve bad weather or some other sort of disaster, a remote database is not going to work very well. The car needs to read the actual sign properly.

melling 7y ago

Waze knows the speed limit and warns you when you exceed it.

Piskvorrr 7y ago
Except when it "knows" wrong, or the limit is conditional (days, hours, vehicle classes), etc.

rypskar 7y ago

How much can you trust that data? My car tell me what the speed limit is by using a database and reading signs. On my commute to work there is a part where it tell me the speed limit is 5km/h when it actually is 80km/h and another place where it for a short bit shows the limit as 80km/h where the correct is 30km/h

leokennis 7y ago
In The Netherlansds (and probably other places), many roads have a different maximum speed between 07:00-19:00 and 19:00-07:00.
- t0mas88 7y ago
  Both Netherlands and Germany have these time based speeds on a lot of highways where the special case is in text underneath the sign. BMW handles it if the navigation database is up to date. At least on the A2 in the Netherlands, which has the 06:00 to 19:00 changes between 100 and 130. It also understands temporary changes for roadworks, but gets it wrong when a roadwork/temporary sign has an exception like "when road is wet" That tells me the camera only understands the main sign and then the navigation database tells it about exceptions / special cases. Nice as a small reminder on your screen, but I wouldn't trust it to self drive based on that data.
joshvm 7y ago
Neither is ideal. But you should use what information you have. There is still no excuse for making a decision like 85 in a 35. Worst case this should be a disengage or the car could defer to you - eg visual warning on the dash "speed limit unclear, override?" In the UK smart motorways can vary from 30mph to 70mph according to traffic. This can change within minutes and obviously cannot be in databases. So this is a good case for sign recognition. In theory though, there is some network that's updating the speed limits and there's no technical reason why that couldn't be a public information service (maybe it already is). Then you have the sibling comments - speed limits which are time based. I would imagine this is country specific and is, mostly, a matter of public record. But would you trust CV to recognise text on a sign with specific hours? I don't know how complex the signage is, but trying to use ML for this seems absurdly wasteful of resources. Finally you have other information - how fast are the cars around you travelling? Have you detected an obstruction on the road (eg cones)? Is the weather inclement and therefore you should drive more slowly, etc. I would imaging that if self driving cars become ubiquitous there will eventually be a system for real time speed limit determination, whether that's some kind of wireless beacon at regular intervals or an online database that's kept up to date I don't know.

Robotbeat 7y ago

Tesla already looks it up in a database. Current Teslas CANNOT have this error simply because MobilEye patented reading speed limit signs and Tesla no longer uses the MobilEye system and haven't since mid-2016.

bsaul 7y ago
side remark : how can you patent a "function" ? Wouldn't mobileeye have to patent a certain way of reading speed limit ?
- brian_herman__ 7y ago
  It is called a process patent.
  - iqtidar 7y ago
    Thanks for the enlightenment!