By Steven G. Goodridge, Ph.D. Member, IEEE
Abstract
Inductive loop sensors, commonly used for detection of traffic at demand-actuated traffic signals, can be configured and adjusted to detect bicycles with metal rims. This article describes how to provide reliable detection of bicycles via inductive loop sensors without generating unacceptable false-positive detection of large vehicles in adjacent lanes.
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Detector Circuit Sensitivity
Detection of a bicycle over a well-designed quadrupole loop requires that the detector circuit be adjusted more sensitive than what is typically required for automobile detection. A bicycle can generate as little as 1% as much change in the loop inductance as an automobile does, especially for a poorly designed loop, because the car covers so much more area of magnetic flux, and has a high net conductivity. However, many commercially available detectors provide adequate sensitivity to accomplish this. According to Jim Magerkurth of US Traffic Corporation, a detector should provide an inductance change sensitivity level down to 0.0025% to reliably detect bicycles. Examples of such detectors include the US Traffic Corporation 262 series rack-mount detectors, which offer nine sensitivity levels. Shelf-mount detectors with this sensitivity include the US Traffic Corporation 921-2, 910 and 913 units. Such modern inductive loop detectors vary in price from $100 to $250. Note that some other models of detector systems on the market offer sensitivity to only 0.01% inductance change; such detectors should be avoided for bicycle-sensitive loop installations.
Good detectors can be adjusted to detect bicycles on quadrupole loops. As described by one signals expert:
It is always possible to set a detector’s sensitivity to pick up a bicycle. The trade-off is in longer detection times and the possibility of false detections from vehicles in adjacent lanes. Most people who set signal detectors use the lowest sensitivity setting that will pick up cars reliably. I advocate using the highest setting that will avoid picking up vehicles in adjacent lanes. Digital circuits used in modern detectors can use high sensitivity settings without unacceptable increases in detection times. Unfortunately, there are still a lot of old detectors out there, and most people who work on signals use principles based on the performance characteristics of old detectors.
– Bob Shanteau, PhD, PE, Registered Traffic Engineer (Source: Rec.Bicycles FAQ)
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Continue reading “Detection of Bicycles at Demand-Actuated Traffic Signals”
Something to bike to: Frank Zappa events Sunday, September 19

2:00PM
3601 Eastern Avenue
Baltimore, MD 21224
Frank Zappa statue to be dedicated on Sunday, September 19 at the Southeast Anchor of the Enoch Pratt Free Library, located at 3601 Eastern Avenue. The event also marks the 25th anniversary of Frank Zappa’s testimony, regarding censorship, to the Senate in 1985.
Participating in the Frank Zappa Sculpture Dedication will be Mayor Stephanie Rawlings-Blake; Gail Zappa, wife of the late Frank Zappa; Dr. Carla Hayden, chief executive officer of the Enoch Pratt Free Library; Jeffery Sharkey, director of The Peabody Institute of The Johns Hopkins University; and Saulius Paukštys of Lithuania.
The dedication ceremony is produced by the Baltimore Office of Promotion & The Arts in partnership with the Enoch Pratt Free Library and the Southeast Community Development Corporation.
The sculpture is a gift to Baltimore City by Saulius Paukštys and Saulius Pilinkus of the Lithuanian nonprofit organization Public Establishment ZAPPART. The sculpture is a replica of artwork in Vilnius, Lithuania by artist Konstantinas Bogdanas. The gift and location were approved by the Baltimore City Public Art Commission.
FRANK ZAPPA EVENTS
The dedication is part of daylong celebration honoring Frank Zappa taking place in the streets of Eastern Avenue and Conkling Street. Immediately following the dedication, Dweezil Zappa and Zappa Plays Zappa performs. For information and details on the performance, visit www.clearpathentertainment.com.
The Creative Alliance hosts a pre-event talk with Gail Zappa and an after party at The Patterson at 3134 Eastern Avenue. For more information, visit www.creativealliance.org.
For information on free parking and shuttle buses, click here.
FRANK ZAPPA BIO
The late Frank Vincent Zappa was a singular musical figure. For three decades he made timeless rock, fusion and avant-garde classical music. Dedicated fans propelled the Baltimore born composer, guitarist, singer and bandleader to media stardom. His interest for music grew during his high school years in Lancaster, California. Shortly after graduation, Zappa would begin a performing and recording career that would soon gain widespread acclaim.
In 1966, he and band members of The Mothers of Invention released debut LP “Freak Out!.” The group went on to do several albums before disbanding. Zappa had solo success, as well, with more than 50 records released during his career.
Known for being an articulate spokesman, Zappa, an opponent of censorship, became a leader of the opposition to the Parents Music Resource Center. On September 19, 1985, he testified before the Senate Commerce Technology and Transportation Committee and shared his opinion on the matter. He later used his testimony in a recording, “Frank Zappa Meets the Mothers of Prevention,” released that same year.
Frank Zappa passed away early in 1993. He has not only become a part of musical history but his legacy still influences the genre today.
Continue reading “Something to bike to: Frank Zappa events Sunday, September 19”
Hiking, biking and tubing in your backyard
By Jaclyn Jones – Examiner
My much anticipated graduation from high school and a deservedly exciting June, July and August made the adjustment to college seem ever so slightly tedious. In just the first week of the semester, it became difficult to apply myself to my studies. So over the extended Labor Day weekend I made an escape…I dusted off my old bicycle and rode it on one of Maryland’s outdoor gems—the Torrey C. Brown Trail, formerly known as the Northern Central Railroad Trail (NCRT).
If you don’t already know about this trail, it’s nearly 20 miles of flat, stone and dirt-covered pathway, highly navigable by bicycle or by foot. The trail is within an easy driving distance from Goucher, Johns Hopkins University, College of Notre Dame, Loyola University, Stevenson University, Towson State University, UMBC and many other local college campuses. It extends from Ashland, which is just off York Rd. in Cockeysville, Md. to the Md.–Pa. line. The trail is part of the rails to trails conversion and follows the path of the now defunct North Central Railway.
Besides biking or hiking, you can tube down the Gunpowder River which runs parallel to the trail. Monkton Bike, Inc. rents tubes and operates the Tube Shuttle between Monkton and Bluemount Rd.
If you work up an appetite, ‘Natural Brothers’ run a deli and café at about the 7-mile marker in Monkton. They offer largely vegan fare and some of the most delicious ice cream—organic, of course!—that I have ever tasted. (Try the Coconut Almond Chip!)
If the great outdoors doesn’t provide enough escapist enjoyment (or food), nearby at York and Shawan Roads is the Hunt Valley Towne Centre with California Pizza Kitchen, Chipotle, Noodles & Company, and Panera Bread.
As a recommendation…If you venture to the trail, pick it up at Monkton or slightly north of there as the more southern points can get crowded.
For more information on the Torrey C. Brown Trail, contact the Department of Natural Resources about Gunpowder State Park.
Before returning to my studies, let me mention that in the coming weeks, I’ll be catching up with several local bands that have performances coming up at the Recher Theater in Towson and I’ll be highlighting some rising stars of the local theater scene as well as other interesting collegians in the Baltimore area!
Continue reading “Hiking, biking and tubing in your backyard”
DZR Shoes Release
by Bike Shop Girl
DZR Shoes.. SPD compatible shoes with style. These are too cool to wait for a full post. Watch the video, visit the website and I’ll write something up fully within 24 hours!

Officials, residents concerned with crosswalks near Cheverly thoroughfare
[B’ Spokes: You know Prince George’s County kills more pedestrains then any other county in Maryland. If you want to see where the 2006 crash data is mapped out here: https://www.sha.state.md.us/OPPEN/BLOC_PrinceGeorge.pdf I have to take issue with Chuck Gischlar statement, you are going to send out a car centric engineer that basically created the problem in the first place and that is going to help how? Not every intersection needs to be cranked up to 11 for motorists, there are options to create the right balance. While not everyone at SHA is car centric it would be nice if they did have a team that had clout and expertise to fix conditions like this rather then having to always bow to our "for the convenience of cars" masters. Next driver awareness??? Just who do you thinks educates drivers and gives them a "grueling" 20 question test… another division of MDOT, yep and we should fix that. Or how about recommending police do a pedestrian sting in the area? I for one am sick of hearing saving a few seconds delay is worth a few pedestrian lives a year.]
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by Natalie McGill | Staff Writer for the Gazette
Jo Bender travels three crosswalks en route to her Cheverly home after 12-hour shifts as an emergency room nurse. Two of those crosswalks pass ramps to a highway: MD Route 50.
Bender said she is scared to face the oncoming traffic that makes left turns from Columbia Park Road onto the Route 50 West entrance ramp. Though drivers must yield to pedestrians on a green traffic light, some may travel too fast to see someone in the crosswalk.
"It’s just too much for one intersection," Bender, 53, said.
Cheverly residents and town officials did a morning walk Friday where they crossed the Columbia Park Road bridge over Route 50 outlining pedestrian and motorist safety concerns such as traffic and crossing signal timing that town administrator David Warrington hopes to bring before the county’s Department of Public Works and Transportation and the Maryland State Highway Administration — two agencies that own sections of Columbia Park Road — in a meeting by early October.
Susan Hubbard, a spokeswoman for the county’s Department of Public Works and Transportation, wrote in a Monday e-mail that any signals on Route 50 would be under the SHA jurisdiction. She said the county maintains 1.7 miles of the road from the train tracks beyond 64th Avenue to Martin Luther King Jr. Highway. She said DPWT has nothing on record from the town with complaints about the traffic and signal issues.
Mayor Michael Callahan, Public Works Director Juan Torres and Warrington observed three problem areas: The intersection of Columbia Park Road, Cheverly Avenue and the Route 50 West entrance ramp; the crosswalk at the Route 50 East exit ramp and the Cheverly Metro entrance at Columbia Park Road.
Torres said one of his suggestions for the Columbia Park Road, Cheverly Avenue and Route 50 West entrance ramp intersection is to do an "all-stop" where in 15 seconds, for example, all traffic would halt for pedestrians to cross. Currently some crosswalks are timed for 25 seconds of crossing time while others are as long as 90 seconds.
Shortly after 8 a.m. Friday, town officials observed Cheverly residents walking and biking from the town entrance to the Columbia Park Road bridge to the Cheverly Metro Station. Even with a glowing white walk signal indicating it was safe to cross, residents still hustled over the crosswalk near the Route 50 West entrance ramp because there were drivers who still had a green light to make a left turn on the entrance ramp to the highway.
Diane La Voy, a 24-year Cheverly resident, said to cross the bridge safely she must start walking just before the walk sign comes on because if she waited until it came on she would be in danger of a car turning left onto the Columbia Park Road bridge from Cheverly Avenue.
"When you get a cross sign it’s like getting a little target on your back," La Voy said.
Del. Jolene Ivey (D-Dist. 47) of Cheverly stood next to La Voy and said she can sympathize with the drivers who wait in a queue during rush hour traffic to make the left turn La Voy mentioned. However she said she believes there’s a way to accommodate both pedestrians and drivers.
Ivey, who is running for re-election said she and Del. Victor Ramirez (D-Dist. 47) of Cheverly, who is running for the District 47 senator seat, typically meet twice a year with the State Highway Administration to talk about priority traffic areas in their district. She said this area needs to make their list but when it comes to a solution it’s all comes down to coordination between the county’s DPWT and SHA.
"It depends on how loud you scream," Ivey said. "It’s a matter of getting the right people to talk to the right people and not letting it fall off your radar screen."
Chuck Gischlar, an SHA spokesman, said they have sent engineers to adjust traffic signals in that area in the past and can send traffic engineers to review the Route 50 crossings again. However, he said it is also up to the drivers to be more aware of pedestrians in the crosswalks.
"It’s important to note that motorists in the area have to be cognizant that it’s a high pedestrian area," Gischlar said.
Cheverly resident Rob Hanson, 39, rides his double seat bike for his two children who attend Cheverly’s Judith P. Hoyer Montessori School and said riding conditions are "less than ideal" because of the amount of traffic going over Route 50 but he prefers walking or biking to driving.
"I generally feel safe as a cyclist and pedestrian," Hanson said. "The timing of the lights I’ve figured out."
Continue reading “Officials, residents concerned with crosswalks near Cheverly thoroughfare”
I Want to Ride My Bicycle…!
by Miranda Hitchcock
I am, admittedly, not a big fan of “exercise.” I don’t like going to the gym, and get bored easily on equipment like elliptical machines. After awful shin splints and stress fractures in high school track I can’t run, and most of my fitness plans begin with the word, “tomorrow.” But recently I had an epiphany: my housemate has a bicycle. My office is close by. Parking is expensive.
And voila! Suddenly I’m a bicycle commuter, riding a bike to work every day that I can. This is good exercise (although the ride is short) but somehow it escapes the negative feeling I usually get with that word. My ride has a purpose and a destination- it takes me to and from my office, and I feel a sense of achievement with each ride that I never got on a stationary bike where you end, literally, where you start. My riding saves me money, since I don’t have to fill a meter with quarters (up to $8/day even without the expensive, likely parking tickets in Bethesda). Riding to work brings a feeling of “goodness” and “greenness,” since I’m not contributing to the belching of pollution and greenhouse gases into the atmosphere from cars.
I get the exhilaration of passing cars as they wait in traffic while I zip by along the sidewalks. As these mornings get a little cooler I get the refreshing wake-up call of the wind to get me ready for work without the coffee and the caffeine. More than anything, I get a few minutes of sanity-improving un-connectedness. A product of my generation, I spend most of my time connected to technology. I’m listening to my iPod, playing on my smartphone, watching TV, surfing the internet… all day, most days. But for the time I spend biking to and from work I have only the physical world around me, and I’m convinced that these few minutes greatly improve my mood and my ability to remain sane throughout a busy workday. All of these factors sum up an important point about sustainability that people often miss- it’s about more than just the environment! Sustainability is about treating our environment well so that it can continue to provide for us in the future. It’s also about treating our bodies and our minds (and our bank accounts!) so that they can provide for us in the future. So while riding a bike to work may not “save the earth,” it has sustainable benefits in many aspects of life.
I don’t know that I will ever take up biking as “exercise,” but I’m certainly glad that I have the ability to bike to work. It’s good for the environment, good for my bank account, good for my health, and good for my mental well-being. That’s a lot of “good!” So until it gets too cold and dreary to ride (and let’s face it, I like “cold and dreary” even less than “exercise”), you’ll see me relatively-slowly but happily bicycling to work. Maybe sometime I’ll catch you doing the same!
Miranda Hitchcock is the Implementation Manager for the Maryland Energy & Sustainability Co-op.
Continue reading “I Want to Ride My Bicycle…!”
The history of the bicycle
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But by 1819, Baltimore had the first bicycle shop in the United States. Soon craftsmen across the United States and Europe were improving on Drais’s ideas. Today, there are more than a billion bicycles worldwide, with about 70 million in the United States, according to the Department of Transportation.
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Continue reading “The history of the bicycle”
Bikestravaganza: Off the Chainring Tour
Upcoming events out east
by Elly Blue
Just a quick post to give y’all a heads-up on our next two (and likely three!) events during our east coast post-tour tour.
In Baltimore it looks like we’ll have two events on Wednesday 9/22. The first one will be a lunchtime brown bag type of thing at the Johns Hopkins public health school. Details coming soon. The second one will be in the evening:
Bikestravaganza! Off the Chainring in Baltimore
Wednesday, Sept 22, 6pm-8pm
The Windup Space, 12 W North Ave
$3-10 sliding scale at the door
(Facebook event listing here: https://www.facebook.com/event.php?eid=154858907867047 )
Officer hits pedestrian in morning crash
[B’ Spokes: OK speculation time again on "Why would a pedestrian want to cross a road a 100′ before the intersection?" So it’s 6:20 in the morning and the road you are walking on has only two crosswalks over one mile. The first crosswalk is one of those "you can only cross from this corner and not the other one" which means if you pressed the ped call button you must first endure a pre-queue so all the "other" pedestrians out at 6:15 in the morning can gather around you and you can all cross together, but if you were in a car the light would begin to cycle right away to emphasize that cars are a privileged class and somehow one car’s convenience out ranks one pedestrian’s life, at least that’s how a lot of ped call buttons work around here. If there was a second crosswalk at least you could press the button on one side and cross a road while waiting, saving a bit of time. So obviously there is disincentive to cross there.
Incidentally, I recently commented to MDOT on what study shows that having only 3 crosswalks improves pedestrian safety? Also what study shows having no zebra stripes or no bar strips in a crosswalk improves pedestrian safety? (per Google maps the next crosswalk is only two parallel lines and no stripes) Maryland has the 6th highest pedestrian fatality rate so you would think they would have some eye on improved pedestrian safety as required by State law. I probably should have also asked what study shows having a pedestrian pre-queue improves safety when there are studies that show removing the pre-queue for cars decreases crashes (as if human nature suddenly is opposite depending on modality of transport.)
Again, my comments may or may not have any bearing on this particular case but I am getting very suspicious of many ped fatalities around low visibility crosswalks. We need to think why these things are happening and take measures to counteract inconveniencing peds more then we do cars. How would people react to MDOT going out of their way to make peds and only ped suffer through a pre-queue when the control box can be set up differently?
Seriously, we need to start thinking differently about accommodating ALL road users. (Article after the fold.)]
Continue reading “Officer hits pedestrian in morning crash”
Sharing the Road Video
After watching this video I have to ask “Where is Maryland’s information for drivers on sharing the road with cyclists?” and “Where is State sponsored cyclists education classes in the Balto metro area?” With the latter at least the Baltimore Bicycling Club has a free class every May. And with the former, Maryland does have something standing on the side lines, though notably fails to address the common right hook and is not mainstreamed into the Drivers’ Manual and other instructional aids. Something else to file away under News you will not see in Maryland.
