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You've omitted an important part of the argument against some facilities: That they increase the likelihood of collisions.

John Allen has a few posts on Davis, CA.



John Allen also has a collection of research papers on the topic as well as his own writings. Since you have a picture of a sidepath on this post I'll include the two links below. But his website is generally quite helpful.


IMO, it is wildly counter productive to label people as irrational, engaging in childish cycling, or anything from the cyclist inferiority mantra. Yes, people are generally scared to ride among motorized traffic. Especially where volume and speed are high. But I think we can address the fear issue as well as design facilities that conform to good traffic principles.

I didn't omit Geof. I just don't think it's valid. There were probably some badly built facilities in 70's and 80's, but the cycling community has largely come to agree that these kinds of facilities are better. Every major biking city in the world has them. Every bike-friendly DOT is building them. LAB supports them. WABA supports them. John Pucher supports them. Studies out of Montreal show them to be both safer and better at encouraging people to ride. NYC has data showing that streets with cycletracks are safer after the installation etc... I'm sorry, but one example of a bad cycletrack in Davis, CA 40 years ago is not exactly something I think needs to be brought up to balance the argument. It sounds a bit like giving the opinion of the one climate-change doubter so that reporting is balanced.

Even in the Davis study they note that after they removed cars to give greater sightlines they fixed the problem, except at driveways where there was "1 collision". They note that when there are no driveways to cross, two-way cycletracks are "probably beneficial." There aren't a lot of driveways in the areas in DC where cycletracks are planned. And where there are, drivers are already on notice due to the large number of pedestrians. So I really don't see this as a problem worth mentioning.

I was not labeling anyone as irrational I'd like to note. I've heard people say that. I've heard people make the case that people who are afraid to ride in the street have no business on a bike. I'm not of that opinion. I think people who are afraid are right to be afraid because they probably lack the experience, training and strength needed to ride on some low BLOS streets. And those streets are less safe, hence the low BLOS. In fact if only 9% of people feel comfortable there and 60% do not, I have to wonder which side is being irrational. But I'm not actually calling anyone irrational. I'm just dismissing that point as unimportant.

If you're going to answer someone else's argument, it is only appropriate to actually present their argument.

I have been waiting see that paper our of Montreal but the research on sidetracks is actually fairly consistent. That is, when enough controls are used to account for something like Simpson's Paradox and high/low risk situations are differentiated, then you indeed find that certain facilities increases risk of collision. For instance, the Helsinki example linked above, the population that uses those sidepaths -- adjacent to the road and completely separated -- is relatively homogenous. Yet the risk of collision is vastly different. Copenhagen facilities also comply with theory too. (http://tinyurl.com/2cu9m4o) Ignoring the studies just increases the likelihood of duplicating their mistakes. Let me emphasize this point, the studies generally point to facility types that increase collisions ... and sometimes why ... not that facilities are bad.

I linked John Allen since he is probably one of the nicest most thoughtful guys around. He has also given expert testimony on cycling and cycling collisions. He doesn't blindly disapprove facilities. Since you brought it up, 15th ST does have the most relevant characteristic associated with high risk sidepaths ... lots of intersections.

I have seen exchanges with Forester. Let's just say that he isn't the most polite person.

Geof, Washcycle, et al.,

Do you have any light to shed on the possible continuum on this matter? I am thinking of the interim alignment for WB&A to Anacostia. (in the long run we need something like the Custis Trail along US-50, with pedestrian bridge accross the beltway to Whitefield Chapel Park, then through Lanham Forest Park, connecting through Washington Business Park to the WB&A, but times are tough). Leaving aside that consulants seem to be leaning in a different direction, I am thinking extending MD-704 to Aardwick Aardmore, then to Pennsy and the eastern 1/2 mile of MD-410.

Cycle tracks have the same possible risks as sidepaths, so I assume that faster roads and fewer cross streets generally makes them a better idea. MD-704 seems to have room for a cycle track accross the Beltway if SHA would tolerate elimination of the shoulder there. I think there could be a sidepath elsewhere. Any thoughts on short cycle tracks to get past a pinch point such as a bridge in a sidepath retroit? A similar situation pertains to MD-410 crossing of US-50, which would be needed in this scenario.

Then we have a 30 mph Aardwick Aardmore which is 60 feet wide with a center lane and 2 lanes in each direction. Bike lanes seem one possibility, but a cycle track on one side and losing the center lane seems a possibility.

Overall, I am thinking that maybe a cycle track would be a logical way to connect two segments that are otherwise trail, given the types of riders to which trails appeal. My assumption is that you would not want a cycle track where there are alot of driveways, and conversely, where SHA has already collected the entrances to make for a limited access highwaym it might as good as a bike lane for road cyclists and far preferable to trail users. There is also some ambiguity about the legality of skates on roadways but not trails.

Geof, I didn't answer they're argument. I said it didn't matter. And I thought the use of the word "you" instead of "I" made it clear that it was someone else's.

My sincerest apologies ... I was interuppted by a little girl that learned (a) where Daddy works and (b) how to open doors.

Just to finish my prior thoughts ...

As you hint with the reference to global warming, we should rely on science and not popular opinion. We keep evolution in our science classes despite over 50% of Americans disbelieving it. So I think the Portland survey -- I assume this is what you used, I did not have an opportunity to check out the link -- is important for knowing what people think. It is much less relevant for determining actual risk levels.

My rough observation: Some of the nasty discourse between vehicular cyclists and ardent facilities people is that they simply arguing different things. VC tend to argue safety and efficiency without considering more cyclists. Facilities people tend to argue more cyclists while implicitly accepting that cycling is generally safe enough and rarely discussing efficiency. Pucher, LAB, and/or WABA are clearly biased on that imaginary scale I painted above. LAB will even pull administrative manuevers to prevent people from running for the board that disagree with their philosophy.

@WC ... Oh, I never thought you meant me and I certainly don't know who told you what. But your short blip is a virtual copy of an extreme VC argument minus the important part about the risk differential. I think that you're generally a fair minded and polite person. So there is no intention of suggesting something nefarious. (Things get lost in written language sometimes. So I want to be clear here.)

@Jim ...

Just based on what I read and my own anecdotes, bridges are generally good places for some facility assuming you can get the resources to properly maintain them. I find that (a) motorized traffic speeds excessively on bridges and (b) windy days make keeping a tight line or decent velocity more difficult. Just be careful with (a) how you enter/exit the facility and (b) right turns. I don't know the area you mention, but one thing I would consider is eliminating right turns until you can effectively get cyclists back into the appropriate position.

I don't know Aardwick Aardmore Rd. And the freakin' firewalls are pissing the hell out of me since Google Maps is being blocked at this moment. But I seem to recall lots of highways around it in PG County and it being somewhat of a connector between other roads. So shooting in the dark, if you need a short connector between two trails separated from the road with little kiddies and such, I'd do it. But you don't want little kiddies and such on there if they are going to have to deal with fast crossing motor vehicle traffic. The cycletrack doesn't really address the problem other than potentially drawing on Safety in Numbers. Otherwise, I would stick with a bike lane and other changes to slow down excessive speeds.

Jim, I'm not familiar enough with the route you're proposing. I guess I always thought they'd do a Custis Trail think along MLK, but if you're going to use Pensey, why not follow that the railroad tracks and then go with a trail along the stream there?

I'll try to clarify a bit, recognizing that we have to differentiate what the Custis-quality trail ultimately needs to be, from the interim trail that we have any decent chance of getting with current funding. (My hope is that the interim trail at least build momentum for a better trail, rather than being on an independent track.)

I understand that the current thinking for the interim "trail" gets to the New Carrollton Metro with Parkwood Street and Ellin Road. So for my purposes here, the question is: How do we get from the west end of the WB&A at MD-450 to there?

It does not hurt to think about both the long-run and the interim. In the long-run, we would hope to see a bridge over the Beltway, and the entire trail either truly off road or using neighborhood streets with low traffic volume and slow speeds, and few crossings over significant roads. In my view, that means a pedestrian bridge over the Beltway and using Lanham Forest Park.

But the interim trail is the most immediate concern. There are only 2 ways to cross the Beltway: MD-704 and MD-450. So one needs to consider the best way to do each. I am leaning toward MD-704 because a sidepath from Lottsford Vista to the other side of the Beltway seems doable, the number of crossings is modest, and improving this part of MD-704 is worth doing on its own anyway, given the lack of a shoulder on a road where people drive 60 mph. Once past the beltway, MD-704 to Sheriff to Minnesota to Benning seems to be the preferred route into DC.

I think that some are pushing the idea of a route that uses MD-450 instead. Perhaps by taking Carter to Lanham Severn, with some sort of sidepath. This strikes me as unlikely to produce an appealing route, given all the driveways there.

But the onus may be on me to prove that a route using MD-704 is better. And part of that task is figuring out how to get from MD-704 to Ellin. Hence the idea of cycle tracks.

But I may be missing some key issues. I would conjecture that you have taken Lanham Severn and maybe even MD-450 to WB&A, and would see why I am a bit dubious about that being the official trail. MD-704 is more out of the way for you.

Although I prefer riding in the street and I'm pretty sure I fall your Enthused and Confident category, I've been going out of my way to ride in the cycletracks just to try them out. Verdict: I still prefer the street, but I can see the appeal to the Interest and Concerned group. I agree that they should be the focus.

There are some safety issues, but overall it's probably safer than a multi-use trail, esp. since faster cyclists can keep riding in the street.

I think those of us that don't really feel the need for bike lanes OR separated facilities need a label too, preferably something not negative. "Enthused and confident" sounds about right, but that's been reserved for a different group.

In a strange way, I think "Interested but Concerned" folks are on to something. Bike lanes are just lines drawn on the pavement, and offer no protection from motorized traffic. In some cases, with some designs I've seen in the city - going around corners and such - it is exceedingly difficult for motorized traffic NOT to violate those lanes.

The seperated facilities I've seen in the city seem to be a vast improvement over the bike lanes. I question the utility and the cost-benefit of some of them (such as the PA Ave lanes) but for the most part, I think those are the facilities that should be pursued. The rest of us can ride our bikes on the road.

Jim, I'm going to need you to lay out where the trail runs from one end to another. You're confusing me. Can you draw a map on Google maps?

Here are three options for getting from the western end of WB&A to New Carrollton. Purple and Green show the alignment thats that Morris Warren, Fred Shaffer, and I explored around 2002 for connecting WB&A to Metro. We might call that the long-term trail, we have a few options. We distinguish roads from trails for that alignment.

Blue shows an alignment that someone has suggested, though I have that 3rd hand. I think they would somehow put some sort of sidepath along the north wide of MD-564, but it is hard to know precisely what that would be.

Red shows the alignment that the Glenn Dale Citizens Association is recommending. In that case there would be sidepath along the north side of MD-704, and then maybe cycle tracks or bike lanes along Aardwick Aardmore and Pennsy, etc.

Blue shows a version that some have proposed but that I do not particularly like.

I also made a map that shows the existing trails and what is in the master plan for MD-704 and the bridges in the New Carollton transit district plan.

OK, now I understand.

I actually like the blue line, but that may be because I bike 450/564 so often as part of my commute. I think it really depends on what happens to 450. There are plans to make it less of a highway and more of a boulevard. If that happens, then this may be the preferred route, but if not then I don't know. It's too bad it can't go along the north side of the RR tracks and under the beltway, but that gets pretty close to people's back yards. Not sure how wide the ROW is there.

As for Aardwick and Pennsey, I do think some sort of cycletrack could make that work. An off road version might hug the beltway and US 50.

Thanks. You may be able to think about this a bit more when you ride that stretch again.

If SHA ever agrees to the road diet along MD-450, I agree that having something along MD-564 would be useful. Though perhaps for a fairly narrow group of people. That is: MNCPPC is looking at bike lanes along a road-dieted road whose traffic continues to travel at 50-60 mph but only using 2 through lanes instead of 3. I would like that--but I do not have a problem with the existing stretch along MD-564 since it already has shoulders, except for the last stretch just after the road goes from 1-lane to 3-lanes westbound, and people go around me. (And here I am not sure they have ROW sufficient to give us much. I am not sure I would ride the proposed sidepath along MD-564, given what it would probably be.

My main concern about the blue line is that I don't see how it can be made into a trail that casual cyclists will take. Along the red routing, a sidepath along MD-704 would have a few roads and almost no driveways, and there seems to be plenty of room for a decent sidepath. By contrast, along the blue routing, I don't see where they get the room for a decent sidepath along MD-564 with all of those driveways and what appears to be a narrow right of way. There are some sidewalks and I can imagine some of them being widened, but the car dealerships cars are almost over the existing sidewalk.

Carter (blue) and Aardwick-Ardmore (red) both have 4 lanes and are good candidates for sharrows, but I am not sure that casual cyclists would take either of those roads as they are. But I can see maybe cycle tracks on Aardwick Aardmore while I don't see them doing it on Carter.

That brings us back to your point about long-term improvements to MD-450. Clearly, adding 2 miles to the WB&A (red) does some immediate good as a 6-mile trail would become 8 miles, and there would then be a trail along the worst part of MD-704 (60 mph cars and no shoulder) for those using MD-704 to Sheriff to get into DC. The blue routing does not seem to have the same sort of immediate benefit to MD-564 because casual cyclists are not on that road anyway, the improvement would not even be to the worst part of that road, that is, they would be adding a sidepath where there already is a shoulder. I'm not sure you or I would even take this new sidepath, if you consider what it would probably look like. Yet they are making it for us because the casual cyclist is not on that road. (I view the worst part of MD-564 the various choke points where the shoulder disappears between MD-193 and the Seabrook Shopping Center.)

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