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Old 04-09-2014, 02:57 PM
 
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Quote:
Originally Posted by urbanlife78 View Post
If you are on a bike and a Prius or Suburban hits the bicyclist, it is going to hurt the bicyclist and the damage is going to be similar regardless of the size of vehicle. For the "ground clearance" to be an issue would mean the one driving the car intentionally ran over a bicyclist that was riding directly in front of them. If you can't see what is in front of you, you shouldn't be driving.
No, it will not be. F=MA. The force of the impact will be equal to the mass of the vehicle and the acceleration (speed). The Suburban has more mass therefore the force will be greater. This is why getting hit by a truck or a train is so dangerous. It isn't just the speed of the vehicle, but it's mass too.


Ground clearance is also an issue because a bike is much more likely to either get thrown in the air by the impact(due to low it's low mass) or to be rolled over by the car after the impact. The bicycle almost certainty will not be upright after any collision due to it's low mass.

In addition if you are on a bike the only things that will dissipate the force imparted by the impact will be your bike and your body.

In an car to car collision the force of impact will be dissipated by the body of the car deforming and the car itself rolling/sliding to an stop. The car's body has bumpers and a body that is built to be crash rated. The bicycle does not. The car's tires and maybe body will be dragged along the ground. In an bike to car accident the bicyclist himself is going to be the one getting dragged or skidding along the ground.

For a driver the greatest danger is being catapulted out your seat and inuring bodily damage. This is why cars have seat belts(to keep you in your seat), Air bags(to provide something softer to hit), collapsible steering wheels and padded dashboards. The bicyclist has no seat belt and only the ground to be catapulted into.

Car vs. bike or bike vs. car is a very uneven match in an accident.
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Old 04-09-2014, 03:00 PM
 
Location: Crooklyn, New York
28,250 posts, read 26,220,119 times
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What are y'all talking about?
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Old 04-09-2014, 03:18 PM
 
Location: Portland, Oregon
46,053 posts, read 29,504,059 times
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Quote:
Originally Posted by chirack View Post
No, it will not be. F=MA. The force of the impact will be equal to the mass of the vehicle and the acceleration (speed). The Suburban has more mass therefore the force will be greater. This is why getting hit by a truck or a train is so dangerous. It isn't just the speed of the vehicle, but it's mass too.


Ground clearance is also an issue because a bike is much more likely to either get thrown in the air by the impact(due to low it's low mass) or to be rolled over by the car after the impact. The bicycle almost certainty will not be upright after any collision due to it's low mass.

In addition if you are on a bike the only things that will dissipate the force imparted by the impact will be your bike and your body.

In an car to car collision the force of impact will be dissipated by the body of the car deforming and the car itself rolling/sliding to an stop. The car's body has bumpers and a body that is built to be crash rated. The bicycle does not. The car's tires and maybe body will be dragged along the ground. In an bike to car accident the bicyclist himself is going to be the one getting dragged or skidding along the ground.

For a driver the greatest danger is being catapulted out your seat and inuring bodily damage. This is why cars have seat belts(to keep you in your seat), Air bags(to provide something softer to hit), collapsible steering wheels and padded dashboards. The bicyclist has no seat belt and only the ground to be catapulted into.

Car vs. bike or bike vs. car is a very uneven match in an accident.
Would you rather be hit by a Prius or a Suburban? My answer would be neither because both would cause serious damage to the bicyclist. The easiest way to avoid this is for people to be aware of their surroundings when driving and to assume everyone driving is a moron while biking.
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Old 04-09-2014, 03:53 PM
nei nei won $500 in our forum's Most Engaging Poster Contest - Thirteenth Edition (Jan-Feb 2015). 

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Location: Long Island / NYC
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Here's a transit project that might make sense for a lower density, small city:

Is Effective Transit Possible in a Transit-Hostile City? « The Transport Politic

no rail, just buses with their own lanes.
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Old 04-09-2014, 04:00 PM
 
Location: Crooklyn, New York
28,250 posts, read 26,220,119 times
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Quote:
Originally Posted by nei View Post
Here's a transit project that might make sense for a lower density, small city:

Is Effective Transit Possible in a Transit-Hostile City? « The Transport Politic

no rail, just buses with their own lanes.
The Mayor of Nashville disagrees.

Quote:
Yet Nashville Mayor Karl Dean maintains that his region is ripe for a massive investment in public transit. One light rail line isn’t enough for him, it seems: he wants a $6.5 billion network to compete with the growing economic heavyweights of Denver, Charlotte, and Austin, each of which have large transit plans of their own.
Nashville Considers Light Rail, but the City’s Unfit for It « The Transport Politic

Gotta keep up with the Charlottes.
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Old 04-09-2014, 04:35 PM
nei nei won $500 in our forum's Most Engaging Poster Contest - Thirteenth Edition (Jan-Feb 2015). 

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Location: Long Island / NYC
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Weird. You found that fast. Amusingly, Charlotte Light Rail (construction cost: $500 million) is almost as expensive the rapid transit line in Rennes, France (€500 million) but with less than 1/8th the ridership.

Rennes Metro - Wikipedia, the free encyclopedia

Odder still is the Rennes rapid transit line uses lower capacity trains than Charlotte Light rail. How do you classify it? The Rennes trains are driverless, with much higher headways.
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Old 04-09-2014, 04:54 PM
 
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Quote:
Originally Posted by nei View Post
Weird. You found that fast. Amusingly, Charlotte Light Rail (construction cost: $500 million) is almost as expensive the rapid transit line in Rennes, France (€500 million) but with less than 1/8th the ridership.

Rennes Metro - Wikipedia, the free encyclopedia

Odder still is the Rennes rapid transit line uses lower capacity trains than Charlotte Light rail. How do you classify it? The Rennes trains are driverless, with much higher headways.
Not really different country and driver-less trains have been possible since the 60ies or 70ies. BART when it opened was to be driver-less, but they changed their tune on that. There were issues of crime and safety and the public felt safer with an employee on board. Smaller trains, depends on the system.

Most of the cost will be in equipment and getting the right of way. A bigger or smaller train won't help much here. Charlotte just built something hoping it would generate more ridership, plus from the look of it, it does not connect to any other light rail lines at the moment(which greatly limits it's use.).
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Old 04-09-2014, 05:04 PM
 
Location: Portland, Oregon
46,053 posts, read 29,504,059 times
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Quote:
Originally Posted by nei View Post
Weird. You found that fast. Amusingly, Charlotte Light Rail (construction cost: $500 million) is almost as expensive the rapid transit line in Rennes, France (€500 million) but with less than 1/8th the ridership.

Rennes Metro - Wikipedia, the free encyclopedia

Odder still is the Rennes rapid transit line uses lower capacity trains than Charlotte Light rail. How do you classify it? The Rennes trains are driverless, with much higher headways.
And to add to it, Rennes rapid transit line is mostly underground. Though looking at the little city, it does a great job of connecting high density areas on each end of the line to the city center and major train lines that run through the city.
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Old 04-09-2014, 05:14 PM
 
Location: Oakland, CA
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Quote:
Originally Posted by orlando-calrissian View Post
I assume that 3 miles is an average for the U.S.? Because I can't think of too many occasions when I drove under 3 miles for any non-work related activity.
I haven't spent much time in Orlando, but in most metros, most things are typically within 3 miles (provided they have enough density, this doesn't mean high density). Even when I lived in a suburban part of South Carolina, the bulk of the stuff we did (besides school) was in a 3 mile radius. Now of course there were no bike lanes or sidewalks, but it wasn't even remotely dense. Definitely more like sprawl. But where my parents currently live in a super rural place, they need to drive about 5 miles to the grocery store etc.

Where I live, in a denser part of Oakland, my 3 mile radius is jam packed with stuff. I've got downtown, Chinatown, 3 "main streets," Koreatown, and stuff in between (in my city limits, not including the stuff in Berkeley in that radius). I could easily find enough stuff to do in the 3 mile radius. I have also lived in more suburban parts of the Bay Area, and 3 miles was the magic number for most errands. Target, groceries, the mall, strip malls etc.

Here is a decent chart about trip distances (compiled by a electric vehicle site)


Source: Can EVs handle the distances we drive? • A Study

They noted people tended to round up to the nearest 5 mile increment. That being said, around 40% of the trips were under 4 miles. This was culled from NHTS data.

And here is the trip distribution too. It is hard to find the breaking point of each mile, but at the marker that looks like it could be 3, it is just over 40% of car trips. And the 4 mile marker is about 50%



This data includes work and non-work trips. So just to reiterate, a lot of people make a lot of really short trips, that potentially could be done without a car.

Now my interest in car-free options, isn't just to promote transit. But if we get people to use other active modes more often, it has huge impacts from a public health, air quality and and a resource perspective (congestion, road capacity, CO2 emissions) There are lots and lots of benefits to creating infrastructure to support "active" modes of transportation.
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Old 04-09-2014, 05:22 PM
nei nei won $500 in our forum's Most Engaging Poster Contest - Thirteenth Edition (Jan-Feb 2015). 

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Location: Long Island / NYC
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Quote:
Originally Posted by chirack View Post
Not really different country and driver-less trains have been possible since the 60ies or 70ies. BART when it opened was to be driver-less, but they changed their tune on that. There were issues of crime and safety and the public felt safer with an employee on board. Smaller trains, depends on the system.

Most of the cost will be in equipment and getting the right of way. A bigger or smaller train won't help much here. Charlotte just built something hoping it would generate more ridership, plus from the look of it, it does not connect to any other light rail lines at the moment(which greatly limits it's use.).
The odd I commented was mainly that mainly that light/rapid transit distinction in train size is gone. In Rennes' case, running slightly smaller trains more often results in more capacity. Rennes complete grade separation probably allow longer frequencies. If the trains have a driver, increased frequency has more of an additional cost. With drivers, less frequent longer trains save money.
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