Question about hazardous curve on the Custis

[NickBull]

Just wondering whether a hazardous curve recently added to the Custis trail is in its “final” configuration or whether it will eventually be modified so that it is less hazardous.

Specifically, the curve is at the top of Rosslyn Hill, after a rider westbound on the trail has past the park near 20th Rd, crossed the bridge over 66, and then makes a turn to parallel the 66 in the direction of Lyon’s Village. The curve is near the new Mom’s. See red exclamation point in embedded map below.

What makes the curve hazardous is primarily that it is an off-camber curve. Many nights on the way home, I see riders coming into the curve with too much speed, then drifting wide into the oncoming lane. It should be really fun in the snow! In addition, there are no lane markings in the curve. And riders joining the Custis from the sidewalk/spur to the left on the map have no signage to tell them that they do not have right-of-way.

Is anyone in charge of approving the work done on this curve, or is it just the construction company that is building Mom’s that was told to make improvements to the bike path, and they think that an off-camber curve is good enough for bicyclists? Is there a plan to put lane markings? Signage?

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Topic

[Tania]

I think this thread relates to the same area?

http://bikearlingtonforum.com/showthread.php?9130-More-Custis-Work-in-a-Different-Location!

In which case, it sounds like it was planned…

[ShawnoftheDread]

It’s not exactly a “new curve.” There was always a turn there, but they realigned it to improve the sight lines in each direction. The new angle has taken some getting used to, but it seems to me to be an improvement over its previous configuration. And I haven’t noticed its being off-camber.

[Steve O]

The “improvement” here definitely helps with sight lines. I don’t know what “off-camber” means, but I have found this curve to be less comfortable than I expected it to be after all the hype. Perhaps that is why.

[NickBull]

@Steve O 126852 wrote:

The “improvement” here definitely helps with sight lines. I don’t know what “off-camber” means, but I have found this curve to be less comfortable than I expected it to be after all the hype. Perhaps that is why.

Off-camber means the road slopes toward the outside of the turn, it’s the opposite of a banked turn. This is not only off-camber, it’s a tightening-radius turn. As you start to go into the turn, the rate of turn is not constant but instead speeds up. The combination of the two is hazardous.

As you come up to the turn headed westward, you can see that it is off-camber–it slopes away from the turn. If you go straight here instead of turning, you are going downhill across the path to exit onto the spur. The only way you can be going downhill across the path there is if it is tilted away from the turn, in other words, off-camber.

You can also stand on the opposite side and watch what happens to westbound cyclists as they come in to the turn and then find that it is tighter than they expected (decreasing radius) and that they are drifting to the outside (off-camber)–they end up in the oncoming lane. Eastbound cyclists would have the same problem except that because it’s at the end of an uphill, most will not be carrying a lot of momentum into the turn.

It’s true that the sight-lines are better, though.

Nick

[dasgeh]

I ride this daily, it seems flat or if anything barely off camber. I’m not sure if it’s a tightening radius, but if it is, again, it’s not severe. What makes it dangerous is that people in the two downhill directions (from Rosslyn on the Custis and from Courthouse on Lee’s sidewalk) come in carrying WAY too much speed. The design was premised on the idea that people would slow down. I’m disappointed that the intersection was not moved/squared off more to seem more like the turn it is. Right now, it seems like, and some people treat it like, the “straight” is Custis – Lee’s sidewalk and the turn is to continue on the Custis. The only problems I’ve had here are when different users have a difference of opinion on who’s “turning”.

All that said, we were promised paint and (I think) signs. Not sure what’s taking so long. I’ll ping the authorities.

[NickBull]

@dasgeh 126888 wrote:

I ride this daily, it seems flat or if anything barely off camber. I’m not sure if it’s a tightening radius, but if it is, again, it’s not severe. What makes it dangerous is that people in the two downhill directions (from Rosslyn on the Custis and from Courthouse on Lee’s sidewalk) come in carrying WAY too much speed. The design was premised on the idea that people would slow down. I’m disappointed that the intersection was not moved/squared off more to seem more like the turn it is. Right now, it seems like, and some people treat it like, the “straight” is Custis – Lee’s sidewalk and the turn is to continue on the Custis. The only problems I’ve had here are when different users have a difference of opinion on who’s “turning”.

All that said, we were promised paint and (I think) signs. Not sure what’s taking so long. I’ll ping the authorities.

If it’s painted with a line going round the curve on the main trail, and with a line down the middle of the “spur” that stops at a perpendicular line before joining the trail, that helps to visually tell people which is the main road and which is the joining road.

The off-camber and tightening radius is subtle, but it’s enough that it makes riders drift out of their lanes.

[dbb]

There are a couple of trail intersections where it might be prudent to establish the “primary flow” of traffic. The split on the MVT and FMR south of DCA comes to mind. Maybe the European approach of painting roadway edge markings to show the primary path might be in order.

I will need to take a look at the new intersection. I’ve ridden it a few times and haven’t noticed anything awry. It is at a topographic crest so I would expect most riders wouldn’t be entering the turn too fast.

[dasgeh]

@NickBull 126926 wrote:

If it’s painted with a line going round the curve on the main trail, and with a line down the middle of the “spur” that stops at a perpendicular line before joining the trail, that helps to visually tell people which is the main road and which is the joining road.

The off-camber and tightening radius is subtle, but it’s enough that it makes riders drift out of their lanes.

Apparently the painting of the trail is the developer’s responsibility and it’s on the punch list (all of this was free to the County; the certificate of occupancy depends on completing the punch list).

According to engineers who have measured it, the radius is constant. Any curve that is not on-camber will required a user to slow down or drift.

[Steve O]

@NickBull 126926 wrote:

The off-camber and tightening radius is subtle, but it’s enough that it makes riders drift out of their lanes.

Nick is right, it is subtly off camber; I noted this morning coming in.
And I have noted a number of “sorry ’bout that” kind of lane encroachments that I am sure are unintentional, but are being influenced by the design.

[DismalScientist]

Hell yes I expect the same level of crappy road design from Arlington. Look at the intersection of George Mason and Washington Blvd.

If people can’t deal with this is is because they are bad drivers or cyclists.

[americancyclo]

I haven’t noticed any issues riding that section eastbound, but I don’t ride it westbound. I have seen one rider come through from the Lee highway sidewalk fast enough to make me slow down more than I used to as I come up that hill from the west.

[Raymo853]

Maybe we should petition for speed bumps to be added to the bike path.

[creadinger]

@Raymo853 126938 wrote:

Maybe we should petition for speed bumps to be added to the bike path.

Adding little ramps to jump off of makes me think that more elevation and in turn, fun, would make this intersection a lot more safe.

We have to think in 3D, people.

[kcb203]

@Raymo853 126938 wrote:

Maybe we should petition for speed bumps to be added to the bike path.

I’ve caught air on some of the little bumps just west of this curve. Not on purpose, though.

[Author]

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