4 ms·

A lot of that is the move to bigger vehicals. Smaller vehicals are overall safer for everyone, minus sometimes the individual because of prisoners delema. Tha

A lot of that is the move to bigger vehicals. Smaller vehicals are overall safer for everyone, minus sometimes the individual because of prisoners delema. That’s countered, or partially, with the ability to not get in an accident being higher due to lower mass though.

giantg2 5y ago
"That’s countered, or partially, with the ability to not get in an accident being higher due to lower mass though." I'm not sure that's really true. There are tons of variables that can affect performance. Like tire size/type, center of gravity, brakes, etc. Driver attention, knowledge, and skill are much more important. I believe 90% of driving is mental and the majority of accidents are due to poor choices, which seem from things like not understanding vehicle capability and limits, not knowing the law, or not paying attention.
- beached_whale 5y ago
  Look at the stopping distances, it's affected by mass F = ma here. The a part is affected by the quality of the tires/breaks/suspension... but that's getting into specifics that don't really fit the generality of the fleet of vehicles getting larger and heavier and their variety in qualities will more time to avoid an accident that they may not have.
  - giantg2 5y ago
    I've never seen stopping distance noted that way. Looks more like force? If you aren't changing other characteristics, then yes increasing mass will increase stopping distance. The problem with this assumption is that things like friction coefficient usually change when you are changing mass (tire size is an obvious one). Most new vehicles stop 60-0 between 120-140 feet. There are heavier vehicles that stop shorter than lighter vehicles. I'm just saying it's not always that vehicles are heavy. The primary variable here (in applied stopping distance) is speed due to the simple fact that reaction time is the same and you are covering distance during that lag, plus velocity is an exponential effect. Here's a good resource. https://byjus.com/stopping-distance-formula/ https://byjus.com/stopping-distance-formula/
  - bradlys 5y ago
    Heavier car doesn’t mean it can’t stop well. If the larger car also has a larger tire contact patch and larger brakes, it can stop just as fast as the smaller vehicle. This shown by many performance SUVs and various other vehicles that weigh in 5000lb+ but somehow come to a stop about as fast as their 3000lb counterparts. Consider the Tesla model s plaid - it has a super fast acceleration rate yet is also stupid heavy. If it can accelerate super fast - it can also stop super fast because the tires work well in either direction. I’ve watched enough brake tests of cars to see this pan out. It’s all about the tires and brakes. Weight doesn’t matter that much when the manufacturer accounts for it.
- tonyedgecombe 5y ago
  It's kind of useless to blame drivers as there is little that can be done to resolve that problem. It would be much better to take a long hard look at road layouts. Engineer them for safety rather than traffic throughput.
  - giantg2 5y ago
    "It's kind of useless to blame drivers as there is little that can be done to resolve that problem." What makes you say that? Most accidents are driver error. The stats show that CDL drivers, who undergo more stringent testing, have a lower accident rate than others. "Engineer them for safety rather than traffic throughput." What would that look like? Even if you replace stop signs with roundabouts, the drivers still need knowledge of how to safely navigate them. If you're talking about reducing speed (technically the most effect if enforced systematically), how do we ensure enforcement?
    - abenga 5y ago
      Roads in the US are too straight and too wide to force drivers to be more deliberate in how they drive. They should have curves, speed bumps, etc. In general anything to force drivers to drive slower around pedestrians, and to reduce the number of times traffic streams cross each other perpendicularly.
      - giantg2 5y ago
        "Roads in the US are too straight and too wide to force drivers to be more deliberate in how they drive." I guess it depends. Most pedestrians are in cities or towns. The roads there may be straight, but not necessarily wide. I'm also not sure how a road being straight and wide is a negative. Making them more narrow and winding is arguably less safe. Even if people reduce their speed, you present new issues of reduced line of sight, decreasing available reaction time. You also have reduced performance (braking on a turn vs straight). Many areas do have some speed bumps. Mostly these are residential or near crosswalks.
        5y ago
- dc-programmer 5y ago
  Larger vehicles have larger blind spots too
  - giantg2 5y ago
    Not really. It depends on the mirror size and geometry. Not to mention many are starting to use an array of video cameras.

giantg2 5y ago

"That’s countered, or partially, with the ability to not get in an accident being higher due to lower mass though." I'm not sure that's really true. There are tons of variables that can affect performance. Like tire size/type, center of gravity, brakes, etc. Driver attention, knowledge, and skill are much more important. I believe 90% of driving is mental and the majority of accidents are due to poor choices, which seem from things like not understanding vehicle capability and limits, not knowing the law, or not paying attention.

beached_whale 5y ago
Look at the stopping distances, it's affected by mass F = ma here. The a part is affected by the quality of the tires/breaks/suspension... but that's getting into specifics that don't really fit the generality of the fleet of vehicles getting larger and heavier and their variety in qualities will more time to avoid an accident that they may not have.
- giantg2 5y ago
  I've never seen stopping distance noted that way. Looks more like force? If you aren't changing other characteristics, then yes increasing mass will increase stopping distance. The problem with this assumption is that things like friction coefficient usually change when you are changing mass (tire size is an obvious one). Most new vehicles stop 60-0 between 120-140 feet. There are heavier vehicles that stop shorter than lighter vehicles. I'm just saying it's not always that vehicles are heavy. The primary variable here (in applied stopping distance) is speed due to the simple fact that reaction time is the same and you are covering distance during that lag, plus velocity is an exponential effect. Here's a good resource. https://byjus.com/stopping-distance-formula/ https://byjus.com/stopping-distance-formula/
- bradlys 5y ago
  Heavier car doesn’t mean it can’t stop well. If the larger car also has a larger tire contact patch and larger brakes, it can stop just as fast as the smaller vehicle. This shown by many performance SUVs and various other vehicles that weigh in 5000lb+ but somehow come to a stop about as fast as their 3000lb counterparts. Consider the Tesla model s plaid - it has a super fast acceleration rate yet is also stupid heavy. If it can accelerate super fast - it can also stop super fast because the tires work well in either direction. I’ve watched enough brake tests of cars to see this pan out. It’s all about the tires and brakes. Weight doesn’t matter that much when the manufacturer accounts for it.
tonyedgecombe 5y ago
It's kind of useless to blame drivers as there is little that can be done to resolve that problem. It would be much better to take a long hard look at road layouts. Engineer them for safety rather than traffic throughput.
- giantg2 5y ago
  "It's kind of useless to blame drivers as there is little that can be done to resolve that problem." What makes you say that? Most accidents are driver error. The stats show that CDL drivers, who undergo more stringent testing, have a lower accident rate than others. "Engineer them for safety rather than traffic throughput." What would that look like? Even if you replace stop signs with roundabouts, the drivers still need knowledge of how to safely navigate them. If you're talking about reducing speed (technically the most effect if enforced systematically), how do we ensure enforcement?
  - abenga 5y ago
    Roads in the US are too straight and too wide to force drivers to be more deliberate in how they drive. They should have curves, speed bumps, etc. In general anything to force drivers to drive slower around pedestrians, and to reduce the number of times traffic streams cross each other perpendicularly.
    - giantg2 5y ago
      "Roads in the US are too straight and too wide to force drivers to be more deliberate in how they drive." I guess it depends. Most pedestrians are in cities or towns. The roads there may be straight, but not necessarily wide. I'm also not sure how a road being straight and wide is a negative. Making them more narrow and winding is arguably less safe. Even if people reduce their speed, you present new issues of reduced line of sight, decreasing available reaction time. You also have reduced performance (braking on a turn vs straight). Many areas do have some speed bumps. Mostly these are residential or near crosswalks.
      - 5y ago
dc-programmer 5y ago
Larger vehicles have larger blind spots too
- giantg2 5y ago
  Not really. It depends on the mirror size and geometry. Not to mention many are starting to use an array of video cameras.