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dasgeh
02-11-2015, 09:44 AM
While I agree that it's not the metric we should use to allocate street space, I do think this kind of analysis is helpful for arguments.



First of all they didn't include enough information to solve the word problem (Is 69 miles too much?). We would need to know how many miles of road DC has. The number is about 1500 miles and about 4000 lane miles. So cyclists-only space is either under-represented (4.6%) or very under-represented (1.7%). But then, of course, that's just a linear measure, if you want to talk about square footage, you basically have to cut the percentage set aside for cyclists in half, because bike lanes are usually half as wide as traffic lanes.

But wait, there's more. It's true that only 4.5% of DC residents commute by bike, but then only 38.9% commute by car. Another 38.5% use transit, 13.6% walk and 4.4% work from home. If we assume that about 1/3 of all transit users ride the bus, then only 69.8% of all commuters are using the roads and sidewalks (bus, car, bike, taxi, motorcycle, walk, other). If we want to apportion that space by mode share, cyclists would get 6.4% of the space, pedestrians would get 19.5% and then 18,4% of the roadway would be reserved for bus-only lanes. Is the Weekly Standard prepared to call for 735 miles of bus-only lanes and 256 miles of bike lanes in DC (because that's the logical conclusion)? That would be awesome.


So, who wants to run the calculations for Arlington? Personally, I think it would be interesting to know, miles, lane-miles, nonprotected bike lanes, protected bike lanes, bike blvd, sharrows, and signed bike routes for the following:

- aerterial roads (Lee Hwy, 50, etc)
- secondary streets (Quincy, Fairfax, etc)
- neighborhood streets

-MUPs (just need miles)

http://www.thewashcycle.com/2015/02/mode-share-is-a-terrible-tool-for-designing-streets-but-if-you-want-to-cars-will-lose.html#comments

DismalScientist
02-11-2015, 10:13 AM
Well, since cyclists are only restricted from freeways, doesn't this mean that cyclist have access to over 99% of lane miles? Since there are likely more miles of segregated bike lanes than limited access lanes, doesn't this mean that cyclists likely have access to more transportation facilities than cars?

The logical conclusion of allocating segregated infrastructure based on mode share is that we are going to get screwed because our mode share is so small.

dasgeh
02-11-2015, 10:24 AM
Well, since cyclists are only restricted from freeways, doesn't this mean that cyclist have access to over 99% of lane miles? Since there are likely more miles of segregated bike lanes than limited access lanes, doesn't this mean that cyclists likely have access to more transportation facilities than cars?

The logical conclusion of allocating segregated infrastructure based on mode share is that we are going to get screwed because our mode share is so small.

"Having access to" and "having safe access to" are very different things. I doubt reasonable people would expect cyclists to bike on 50, even though it's legal. Hence the need for the breakdown in road type.

lordofthemark
02-11-2015, 10:44 AM
Well, since cyclists are only restricted from freeways, doesn't this mean that cyclist have access to over 99% of lane miles? Since there are likely more miles of segregated bike lanes than limited access lanes, doesn't this mean that cyclists likely have access to more transportation facilities than cars?

The logical conclusion of allocating segregated infrastructure based on mode share is that we are going to get screwed because our mode share is so small.


Drivers have access to standard (paint only) bike lanes too - not only the striped areas designated for turns, but they can legally cross them to park, and IIUC they can enter them when required for safety reasons (such as to get out of the way of an emergency vehicle)

So possibly only protected bike lanes should be counted as bike only infra. Though in that case we should also add runners to the number of users. ;)