4 ms·

The capacity issue is relevant, but roads require maintenance due to large trucks and weather, not cars. Asphalt damage increases with the cube of the vehicle w

by khafra 8y ago

The capacity issue is relevant, but roads require maintenance due to large trucks and weather, not cars. Asphalt damage increases with the cube of the vehicle weight.

wlesieutre 8y ago
Worse, it's to the fourth: https://en.wikipedia.org/wiki/Gross_axle_weight_rating https://en.wikipedia.org/wiki/Gross_axle_weight_rating Road damage rises steeply with axle weight, and is estimated "as a rule of thumb... for reasonably strong pavement surfaces" to be proportional to the fourth power of the axle weight. This means that doubling the axle weight will increase road damage (2x2x2x2)=16 times. For this reason trucks with a high axle weight are heavily taxed in most countries. For a more concrete example, compare a Honda Civic (about 3000 lbs including passengers) and a bike + rider (call it 250 lbs). The ratio of road damage is 3000^4 / 250^4. The car does over 20,000x as much damage to the road. And heavy trucks are much much worse, hence the taxes that wikipedia mentions. I've heard people complain that bikes don't pay gas taxes to fund road work. While that may be true of new construction, nobody's ever repaved a road because too many bikes rode on it. And if we're talking about taxing bike riders to pay for new construction, how about we spend it on separated bike paths instead of dumping it into more roads for cars? No bike rider wants to be sharing the road with you, it's just the only option in most places.
- Retric 8y ago
  Rods have finite lifespans independent of usage. You will need to repair bike lanes that only see bike traffic. Remove semi trucks from the road and total budget for road repairs drops slightly but far less than your analysis suggests.
  - adrianN 8y ago
    I don't think I've ever seen a sidewalk being replaced because of age (or any other reason for that matter). Bike paths don't suffer much more wear. I think you underestimate the life span of asphalt.
    - dsfyu404ed 8y ago
      >I don't think I've ever seen a sidewalk being replaced because of age Walking over uneven surfaces is much more comfortable than using a wheeled vehicle, so long as those surfaces are flat. Everyone will bitch and moan about a road that's in rough shape. Nobody really cares if it's a sidewalk (sucks for the disabled though). I've seen sidewalks get replaced due to age but I don't live in CA where it's 70 degrees year round.
    - wlesieutre 8y ago
      They do wear out eventually. Most sidewalks that I've seen destroyed were from tree root upheave though.
    - Retric 8y ago
      Many places have relatively new construction, so it's not yet been an issue. It's rather common for older cities like DC, or places with a lot of freeze cycles and or trees. https://ddot.dc.gov/service/sidewalk-repair https://ddot.dc.gov/service/sidewalk-repair

by khafra 8y ago

The capacity issue is relevant, but roads require maintenance due to large trucks and weather, not cars. Asphalt damage increases with the cube of the vehicle weight.

wlesieutre 8y ago

Worse, it's to the fourth: https://en.wikipedia.org/wiki/Gross_axle_weight_rating https://en.wikipedia.org/wiki/Gross_axle_weight_rating Road damage rises steeply with axle weight, and is estimated "as a rule of thumb... for reasonably strong pavement surfaces" to be proportional to the fourth power of the axle weight. This means that doubling the axle weight will increase road damage (2x2x2x2)=16 times. For this reason trucks with a high axle weight are heavily taxed in most countries. For a more concrete example, compare a Honda Civic (about 3000 lbs including passengers) and a bike + rider (call it 250 lbs). The ratio of road damage is 3000^4 / 250^4. The car does over 20,000x as much damage to the road. And heavy trucks are much much worse, hence the taxes that wikipedia mentions. I've heard people complain that bikes don't pay gas taxes to fund road work. While that may be true of new construction, nobody's ever repaved a road because too many bikes rode on it. And if we're talking about taxing bike riders to pay for new construction, how about we spend it on separated bike paths instead of dumping it into more roads for cars? No bike rider wants to be sharing the road with you, it's just the only option in most places.

Retric 8y ago
Rods have finite lifespans independent of usage. You will need to repair bike lanes that only see bike traffic. Remove semi trucks from the road and total budget for road repairs drops slightly but far less than your analysis suggests.
- adrianN 8y ago
  I don't think I've ever seen a sidewalk being replaced because of age (or any other reason for that matter). Bike paths don't suffer much more wear. I think you underestimate the life span of asphalt.
  - dsfyu404ed 8y ago
    >I don't think I've ever seen a sidewalk being replaced because of age Walking over uneven surfaces is much more comfortable than using a wheeled vehicle, so long as those surfaces are flat. Everyone will bitch and moan about a road that's in rough shape. Nobody really cares if it's a sidewalk (sucks for the disabled though). I've seen sidewalks get replaced due to age but I don't live in CA where it's 70 degrees year round.
  - wlesieutre 8y ago
    They do wear out eventually. Most sidewalks that I've seen destroyed were from tree root upheave though.
  - Retric 8y ago
    Many places have relatively new construction, so it's not yet been an issue. It's rather common for older cities like DC, or places with a lot of freeze cycles and or trees. https://ddot.dc.gov/service/sidewalk-repair https://ddot.dc.gov/service/sidewalk-repair