Design Template by Bikingtoronto

« New rumble strips before Memorial Circle | Main | Is bike-sharing making conflict more pronounced? »

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

i hope MD SHA doesn't sell that as a cycling improvement. They should take one of the three lanes each way for buffered lanes. They've tried everything short of speed bumps to slow cars on that stretch, but nothing works because it's three lanes v. two inside the DC line, drivers gun it heading northbound, and are still in Beltway mode coming southbound. Calm traffic, induce bikes off the sidewalk, and save the trees - take a lane.

Sidewalks there definitely need some remedial attention for peds though. ‘Who is going to want to walk on that sidewalk if there isn’t any shade?’ The many car-free domestic staff that ride the bus, and work in the beautiful mansions on that stretch.

Re: extra summer power at the CaBi stations -- How 'bout some big box fans that we can use to cool ourselves after docking?

Re: extra power, i don't think there is any. Stations are designed to have very little 'passive' power draw. Most power expended only when interacting with the station, triggering power-on with a fob or the keypad. So any extra power generated in summer consumed by extra power use because of higher ridership

Isn't the solar panel just a trickle charger for the battery?

Darren, SHA isn't trying to sell it as a cycling improvement but to provide a facility that is ADA compliant. The existing sidewalk doesn't satisfy those requirements and has several parts that are simply inadequate. In order to properly rehab that sidewalk to meet everyones needs then all the trees lining the street would have to come down. While I'm personally in favor of an on-road cycling facility such as mid road contra-flow bike lanes (which was shot down by SHA due to the necessary removal of trees) SHA is not going to shut down a lane of traffic for that purpose. The ADA selling point is important as part of this facility is being paid for using ADA funds.

If you put a better sidewalk at this point on Wisconsin, most cyclists will use it. That stretch is one of the fast, no-shoulder variety that scares the bejesus out of the great majority of riders, though I've actually found it to be pretty safe becuase it has three lanes and good sight distances. Heck, most use the crappy one that's there now. So might as make it the best darn sidewalk we can.

I will use it! For a safe route for me and my son on his bike trailer from my home in Friendship to Bethesda, I either must take the sidewalks on Connecticut Avenue to the east or the CCT to the West, both of which add 10 minutes to the commute. I don't think this stretch will end up being used much by pedestrians, who already tend to use the west side, 5 foot wide sidewalk. I understand the desire to have a bike lane on this stretch of Wisconsin - it will never happen for the reasons stated above. So think of this as, mostly, an 8 foot wide bike path that will predominantly be used by cyclists.

BTW: the NIMBYs in Chevy Chase DC hate this idea, as they hate any bike related infrastructure because they see it as another camel's nose under the tent toward further reducing their ability to drive and park where they want. For this reason alone, all cyclists should support the initiative.

Finally, while I don't advocate tree felling, there will still be a lot of trees abutting the path, as the Chevy Chase club basically has left a buffer of foliage between Wisconsin and their blessed golf course.

Put a small, battery-backed charger on each bike, and people can charge while they ride. Would require modifying the docking setup, obviously, but something to think about for the next design.

darren, there has to be extra power, or the thing would be shutting down all the time. It has to be able to create enough power during a winter day to get through a winter night. There might not be much, but there is surely some.

Charlie, I think so. Just a trickle charge. Not enough to run a box fan - sorry - but that's why I suggested phone charging.

@charlie is right. The only way those PV panels work is by direct feeding a battery. There may or may not be a Pepco connection - depending on the location - and I bet CaBi has real time data on PV output and battery life so they can hot-swap a battery out if there's a problem.

As far as solar availability - the summer/winter spread isn't *that* significant. NREL's PVWatts tool gives the solar radiation values for the 40km square around DC.
Nov/Dec/Jan is around 3.5kWh/m2/day; shoulder season months (spring, fall) are around 5kWh/m2/day and summer is around 5.5kWh/m2/day.

They're certainly not exporting to Pepco so at best they could plug something into the battery other than the station computer. I like antibozo's idea for a battery on the bike for on-the-go charging. Although all the charge-discharge would wreck those batteries and shorten lifetime.

Bilsko, I suspect they either send power to a battery and run everything off the battery or they can run everything off either the battery in dark and the panel in sun. That's how the satellites I work on do it.

The difference in solar availability you give is over 50% more power in the summer. That's pretty significant in my book. I'd call a 50% raise pretty significant, for example.

No the stations aren't hooked up to PEPCO. That's the whole reason for the panels. But there is no reason that excess power couldn't be routed to something else once the battery is fully charged. You'd have to redesign the whole electronics, but it's doable.

I suspect that the satellites you work on are much less picky about things like voltage sags (not really an issue since there aren't clouds passing in front of the panels when they're a couple hundred miles up in space).
For -relatively- sensitive equipment like the CaBi station computer, you want to keep the incoming AC voltage within 5% of 120V and the panels by themselves would have a hard time doing that - hence my guess is that its going through a battery.

It could all be in a DC setup (with no inverter/rectifier) and skip AC altogether...I guess it just depends on how the computers are configured. If its a standard 120V PSU, then its expecting AC....otherwise they need something to kick out 12V for the motherboard, and 5V for other components (peripherals, communications, etc.)...and whatever the monitor takes.

I agree that the *relative* spread is significant...but the *absolute* spread is actually quite small. To be honest I haven't seen any of the panels up close so I don't know how big they are/what they're rated at. I'm assuming its somewhere between 200-300W - if there's enough space. Could be much smaller: 50-100W [ Update: I just saw a picture and those are tiny tiny panels... my guess is no more than 100W]

The computer will probably be drawing around 50-100W under load and then another 20-30 for the monitoy. All the other electronics on board probably draw another 50W.

We're talking really small amounts here. But, then again, it doesn't take a lot to charge something like a cell phone or a GPS device on a bike...it could be a great idea.

Re: extra summer power at the CaBi stations.

Have CaBi stations wired to nearby buildings to cut business' and tenants' PEPCO bills. It'll create good will. Drivers, bicyclists and pedestrians alike hate PEPCO's management.

I'm afraid the CaBi stations wouldn't be able to generate enough power to offset the cost of setting up and maintaining a grid connection to adjacent buildings.

I was thinking putting USB charge ports in the bikes would require a change to the dock, but now i think about it, there are lights on the bikes. How are those charged? Do they run off a dynamo, have batteries replaced by CaBi maintainers, or charge from the dock? If the latter, it would be trivial to add a USB port for charging on the bike; they might want to upgrade the internal battery tho.

I think it's a dynamo in the bikes, but sometimes I see the lights on after they've docked, so maybe there is a battery.

CB lights are run by an dyno from the bike wheels. A small battery on the bike stores some of the dyno generated juice so that the lights stay on for a minute or so when the wheels stop. Useful at stop signs and traffic lights!

Chris, thanks for the info.

I guess unless the dynamo and battery are upgraded there prolly isn't enough juice left over in the bike to charge anything.

The proposed sidewalk, while useful, will have serious safety issues for bicyclists. According to SHA, the sidewalk will be 5'-6' wide for about 800' of its length. Most of the sidewalk will have only a 2' grass buffer separating it from the curb, and the southernmost 250' looks like it will have no separation at all (and is only 5'-6' wide there). If you've ever ridden on a sidewalk with no separation from the curb, you know that 1) don't bring your children, 2) pray you don't hit a rock and fall into the street. First I characterized it as a path, but no, it shouldn't be called that.

The comments to this entry are closed.

Banner design by creativecouchdesigns.com

City Paper's Best Local Bike Blog 2009

Categories

 Subscribe in a reader