4 ms·

That just means they add bicycle setbacks in an attempt to scare drivers. It doesn't solve the problem when people are routinely allowed to drive without demons

by gok 7y ago

That just means they add bicycle setbacks in an attempt to scare drivers. It doesn't solve the problem when people are routinely allowed to drive without demonstrating an understanding of how a traffic light is supposed to be interpreted.

TulliusCicero 7y ago
It does partially solve the problem. Protected intersections make lanes of walking and biking much more obvious to drivers, and the curbs are such that drivers slow down more and have better visibility.
- u801e 7y ago
  Except for the fact that the bike lane is hidden by parked cars until shortly before getting to the intersection. What do you see in this image: https://imgur.com/a/JcS4RK5 https://imgur.com/a/JcS4RK5 The other thing is that if you go by the figures and text in https://nacto.org/publication/urban-bikeway-design-guide/dont-give-up-at-the-intersection/ https://nacto.org/publication/urban-bikeway-design-guide/don... on pages 12 and 13, you'll find that a right turning driver can only see about 8.2 feet to their right when making a turn. That's the only opportunity they have to see an approaching cyclist who comes from behind them moving at 16 feet per second. A half second to react to a cyclist appearing in the driver's field of view (as shown as the picture on page 13) is not enough time for a driver to yield.
  - TulliusCicero 7y ago
    Not all protected bike lanes are parking protected. Don't think this is common in the Netherlands. Parking protected is better than having bikes on the other side of parked cars, but yes visibility is less than ideal. Anyway, you're ignoring the other two things I pointed out about protected intersections. It makes the bike lane itself more obvious, and the curb design forces drivers to slow down more.
    - u801e 7y ago
      > Parking protected is better than having bikes on the other side of parked cars, but yes visibility is less than ideal. Without visibility, the motorist and cyclist could be on a collision course and not even know it until it's too late. On the other hand, if the cyclist is on the road in the middle of the general purpose traffic lane, the motorist will see them in advance and either change lanes to pass or slow down and wait until it's safe to do so. At intersections there won't be any turning conflicts because the turning motorist is either directly in front or directly behind the cyclist (meaning the motorist won't cross the path of the cyclist when making their turn). The fact is that the vast majority of motorist/cyclist collisions occur at intersections, so it makes more sense to cycle in a way such that you're visible to other drivers between intersections and follow the vehicle traffic rules when proceeding through one.
      - TulliusCicero 7y ago
        > Without visibility, the motorist and cyclist could be on a collision course and not even know it until it's too late. No. You don't seem to understand how protected intersections work. The design of the intersection itself forces cars to slow down quite a lot to make the turn. You can see this here: https://images.app.goo.gl/XnppCCtEhs8vdgd39 https://images.app.goo.gl/XnppCCtEhs8vdgd39 Plus, generally you make the parking lane end a bit before the actual intersection, precisely to improve visibility. Anyway, as I said, parking protected is not the ideal situation anyway. It's a compromise with municipalities that aren't ready to give up more street parking in the interest of safety. What you're describing is vehicular cycling, which has been a complete failure. There are zero countries that use it with high rates of safe biking, whereas there are a bunch of countries that use protected lanes and intersections with success that directly correlates with how much they're used, with the Netherlands being the foremost example.
        u801e 7y ago
        > No. You don't seem to understand how protected intersections work. I'm well aware of how NACTO[1] claims they work. > The design of the intersection itself forces cars to slow down quite a lot to make the turn. According to NACTO, they make drivers slow down to about 10 mph to make a right turn (see page 11, paragraph 2, sentence 1). > Plus, generally you make the parking lane end a bit before the actual intersection, precisely to improve visibility. This doesn't address the case where a cyclist approaches the motorist from behind from the motorist's point of view. In other words, the only time the motorist will have a chance to see the cyclist is when they're in the process of making a right turn. We can't assume that the cyclist will yield to a motorist or even be paying attention to the adjacent roadway (think of an 8 year old cyclist who doesn't have the concept of how intersections work). The document makes the assumption that a cyclist will traverse 50 feet in 3 seconds (about 16.67 feet per second which is about 11.4 mph). On page 13, they have a figure depicting the motorist's field of view as they make their way around a protected at a speed of around 10 mph. If you measure the bikeway setback line shown on page 12 and compare it with the horizontal measurement from the drivers field of view cone (from the origin to the left most extent), you'll find that the driver can only see about 8.2 feet down the bikeway. Remember that both the cyclist and the car are traveling at a speed of around 15 feet per second. Also, the average reaction time of someone who's not expecting an event is around 1 to 1.5 seconds. This means that the motorist will not have enough time to see the cyclist in order to yield to them. The picture right below it showing the cyclist entering the intersection makes that evident. > What you're describing is vehicular cycling, which has been a complete failure. Vehicular cycling is the safest way to cycle in the current environment and addresses the problems of intersection conflicts by positioning the cyclist right in front of the motorist who will have no trouble seeing them well in advance of catching up to them. The sidepath type intersection actually increases conflicts due to lack of visibility as I described above. [1] https://nacto.org/wp-content/uploads/2019/05/NACTO_Dont-Give-Up-at-the-Intersection.pdf https://nacto.org/wp-content/uploads/2019/05/NACTO_Dont-Give...

by gok 7y ago

TulliusCicero 7y ago

It does partially solve the problem. Protected intersections make lanes of walking and biking much more obvious to drivers, and the curbs are such that drivers slow down more and have better visibility.

u801e 7y ago
Except for the fact that the bike lane is hidden by parked cars until shortly before getting to the intersection. What do you see in this image: https://imgur.com/a/JcS4RK5 https://imgur.com/a/JcS4RK5 The other thing is that if you go by the figures and text in https://nacto.org/publication/urban-bikeway-design-guide/dont-give-up-at-the-intersection/ https://nacto.org/publication/urban-bikeway-design-guide/don... on pages 12 and 13, you'll find that a right turning driver can only see about 8.2 feet to their right when making a turn. That's the only opportunity they have to see an approaching cyclist who comes from behind them moving at 16 feet per second. A half second to react to a cyclist appearing in the driver's field of view (as shown as the picture on page 13) is not enough time for a driver to yield.
- TulliusCicero 7y ago
  Not all protected bike lanes are parking protected. Don't think this is common in the Netherlands. Parking protected is better than having bikes on the other side of parked cars, but yes visibility is less than ideal. Anyway, you're ignoring the other two things I pointed out about protected intersections. It makes the bike lane itself more obvious, and the curb design forces drivers to slow down more.
  - u801e 7y ago
    > Parking protected is better than having bikes on the other side of parked cars, but yes visibility is less than ideal. Without visibility, the motorist and cyclist could be on a collision course and not even know it until it's too late. On the other hand, if the cyclist is on the road in the middle of the general purpose traffic lane, the motorist will see them in advance and either change lanes to pass or slow down and wait until it's safe to do so. At intersections there won't be any turning conflicts because the turning motorist is either directly in front or directly behind the cyclist (meaning the motorist won't cross the path of the cyclist when making their turn). The fact is that the vast majority of motorist/cyclist collisions occur at intersections, so it makes more sense to cycle in a way such that you're visible to other drivers between intersections and follow the vehicle traffic rules when proceeding through one.
    - TulliusCicero 7y ago
      > Without visibility, the motorist and cyclist could be on a collision course and not even know it until it's too late. No. You don't seem to understand how protected intersections work. The design of the intersection itself forces cars to slow down quite a lot to make the turn. You can see this here: https://images.app.goo.gl/XnppCCtEhs8vdgd39 https://images.app.goo.gl/XnppCCtEhs8vdgd39 Plus, generally you make the parking lane end a bit before the actual intersection, precisely to improve visibility. Anyway, as I said, parking protected is not the ideal situation anyway. It's a compromise with municipalities that aren't ready to give up more street parking in the interest of safety. What you're describing is vehicular cycling, which has been a complete failure. There are zero countries that use it with high rates of safe biking, whereas there are a bunch of countries that use protected lanes and intersections with success that directly correlates with how much they're used, with the Netherlands being the foremost example.
      - u801e 7y ago
        > No. You don't seem to understand how protected intersections work. I'm well aware of how NACTO[1] claims they work. > The design of the intersection itself forces cars to slow down quite a lot to make the turn. According to NACTO, they make drivers slow down to about 10 mph to make a right turn (see page 11, paragraph 2, sentence 1). > Plus, generally you make the parking lane end a bit before the actual intersection, precisely to improve visibility. This doesn't address the case where a cyclist approaches the motorist from behind from the motorist's point of view. In other words, the only time the motorist will have a chance to see the cyclist is when they're in the process of making a right turn. We can't assume that the cyclist will yield to a motorist or even be paying attention to the adjacent roadway (think of an 8 year old cyclist who doesn't have the concept of how intersections work). The document makes the assumption that a cyclist will traverse 50 feet in 3 seconds (about 16.67 feet per second which is about 11.4 mph). On page 13, they have a figure depicting the motorist's field of view as they make their way around a protected at a speed of around 10 mph. If you measure the bikeway setback line shown on page 12 and compare it with the horizontal measurement from the drivers field of view cone (from the origin to the left most extent), you'll find that the driver can only see about 8.2 feet down the bikeway. Remember that both the cyclist and the car are traveling at a speed of around 15 feet per second. Also, the average reaction time of someone who's not expecting an event is around 1 to 1.5 seconds. This means that the motorist will not have enough time to see the cyclist in order to yield to them. The picture right below it showing the cyclist entering the intersection makes that evident. > What you're describing is vehicular cycling, which has been a complete failure. Vehicular cycling is the safest way to cycle in the current environment and addresses the problems of intersection conflicts by positioning the cyclist right in front of the motorist who will have no trouble seeing them well in advance of catching up to them. The sidepath type intersection actually increases conflicts due to lack of visibility as I described above. [1] https://nacto.org/wp-content/uploads/2019/05/NACTO_Dont-Give-Up-at-the-Intersection.pdf https://nacto.org/wp-content/uploads/2019/05/NACTO_Dont-Give...