Accomodating bike speeds by re-timing signals on Valencia Street

Friday, January 30, 2009

Accomodating bike speeds by re-timing signals on Valencia Street

As the cyclists in this video point out, re-timing signals for bike speeds (Green Wave) would make roads safer for all street users on Valencia Street. Before even mentioning re-timing signals, this was many cyclists' top request to improve their journey.

Recently, the San Francisco Municipal Transportation Agency (MTA) found that during peak commute times vehicles run more efficiently when signals are timed at the speeds they actually travel during congestion -- 12 to 15 mph -- rather than the current 25 mph. Major bike streets in Portland, the Netherlands and Denmark have been timed for bike speeds and now it is time for San Francisco to ride the Green Wave! For more information read my previous SF Streetsblog article on the topic.

http://www.livablestreets.com/people/geekguyandy Andy Goodell

I don't know this street since I live in New York state, but I would imagine that a lot of the car traffic speeds up, hits a red light, then speeds up to the next intersection. If the lights are timed for a slower pace, then cars would get through much more efficiently without having to accelerate just to brake 100 feet later. Bike-speed timing should also allow more time for vehicles to move through the intersections so that they never become clogged.
-Andy
http://www.gpscruise.com jim

Here's another way to go.
Put a bike-bridge at needed intersections.
A bike-bridge is an up-down ramp over the stoplight.
It is for bikes only.

It would be cheap to build and install.
Specs:

4ft wide. Single file please.
15ft tall at center point.
Holds 1-ton only (10bikers).
4inch grate lets in bike wheels only.

gpscruise@gmail.com
-jim
LBJ’s Love Child

Actually, I prefer the signals to be timed for cars. The light turns green, the queue of cars and trucks proceeds ahead of me, and I am left in car-free peace until I come back upon the end of the queue at the next stop light. Why in the hell would I want to ride in the middle of a pack of cars, in the gutter lane or not?
http://xingcolumbus.wordpress.com/ John

This is an interesting idea, but presents a challenge since not all cyclists travel the same speed. Some travel 12 to 15 as you suggested, but some can travel 20+ mph. I typically do about 17-20 on paths and 20-23 on roads, but that can vary significantly depending on wind speeds too.
http://www.livablestreets.com/people/janel Janel Sterbentz

Re: LBJ - On Valencia St. cyclists are hardly ever "left in car-free peace." After the queue of cars proceeds through the intersection, there are always cars rushing by afterwards, either from the previous intersection, or cars turning onto Valencia from cross streets. If signals were timed for 12-15 mph, and ideally the speed limit as well, cars will travel the same speed as bikes making it less dangerous and more comfortable to bike.

Re: John - Since the green light stays green for a minute or more, slower and faster cyclists can have some wiggle room to adjust their positioning along the corridor to meet all green lights. For instance, a slower cyclist will proceed through the first intersection as soon as the light turns green, and by the end of their journey they will just be getting through the yellow light. The faster cyclist can travel slowly to reach the yellow light in the beginning of their journey, and by the end they will be hitting the intersection just as the signal turns green. The green phase can be shortened or lengthened to achieve maximal flow for the majority of cyclists.
Steve Glanzer

Good call! I would say time it for the upper-end of the bike speed range. Steady flow it's the way to go! Valencia street is heavily commercial and I think it would be good for business too making it easier for drivers to spot shops, restaurants, and parking. If you want to want to drive through the area quicker, stick to Guerrero Street or South Van Ness.
http://www.livablestreets.com/people/vhamer vhamer

i really like the wider video format.
bayareabiker

Its also worth noting that slower speeds actually improve traffic flow for cars in urban areas - slower speeds means less space between cars means more cars can travel in the same amount of road space. Of course, as the article says, the cars are already going that slow anyway. As much an issue of MTA adjusting to reality of traffic speed as promoting safe bike travel.
Amy

As someone who lives in the Mission and bikes Valencia most days of the week, I love this idea. Timing the lights to bike speed would definitely make my ride safer and more pleasant. However, I'm a little uncomfortable with the strong emphasis in the video on how this would prevent bikers from running red lights. I just don't think that approach is going to win us much sympathy with drivers. Honestly, when bikers run red lights, they know they're doing it at their own risk. We (well, I) get pissed when drivers violate traffic laws; why would the reverse be any different? Instead, our advocacy efforts might want to focus more on the improved travel time efficiency for everyone -- bikes & cars. And the improved safety for bikers "taking the lane" when dealing with the all-too-common illegally parked cars in the bike lane. On any given ride I usually have to swerve around 4-6 of those jerks! Great idea though. You've got my support.
david

isn't there an issue that if you time the light for one direction then aren't they out of sync for the other direction? is there clear time of day weighting for one direction of bikes or the other?
http://www.livablestreets.com/people/janel Janel Sterbentz

Somehow the traffic modeler was able to synchronize the timing for both directions simultaneously. There is a slight uphill on Valencia so we would time the signals around 15 mph on the downhill going inbound in the morning and about 12mph on the uphill outbound in the evening.
Karl

This is the closest video I could find in just a minute or so of searching unsuccessfully for modern bikes in a film- by which of course I mean those that acknowledge the invention of the motor.

Why do cars move faster in urban areas? Because our muscles especially if asked to power appropriately wide tires are inadequate.

Those who look at bikes as fun, as a way of getting exercise while transporting themselves, are becoming too much of the problem.

They lack ambition and deny the fact that there is a lot of time in the day to get exercise outside of your commute if by increasing the speed of it you have less time to exercise in it. Standardising bike speeds, establishing minimum speeds for low mass vehicles like bikes, is prevented by ourselves!

Yes most cities have bike lanes that are underutilised and those who get this freebie want to keep it to themselves selfishly- so they are stuck with a narrow horrific path they guard pathetically.

If you are able to keep up with a real vehicle that may have a smaller carbon footprint then your 'human powered' toy congratulations you are welcome. But abandon please the sense of entitlement that hogging more asphault then a speeding SUV consumes by barely breaking into the teen MPH's and then only downhill or downwind that far too many daily commuters settle into.

Bogota for example could take advantage of the calmed roads withouto having to have dedicated lanes by speeding up the single passenger vehicles on them so as to not have the hundreds of passengers vehicles risk overtaking them as often or at all if properly timed onto the road (if a bus is too closely following you have to wait untilk it passes to enter the road so as to assure you get to the next point before one has to pass you).

that we are jumping over bikes to install batteries in cars should not be ignored!

Slow bikes congest. Road bikes are ridiculous. Very well engineered motorised bikes, bikes that perhaps have thousands of dollars spent on mature technology instead of ritzy basket weaving elitist fetishtic degrammification, only them, can spare the world excessive peanut butter etc. consumption.
Southvannesstraffic

Folsom and Bryant are better...far less traffic. A bit slower but a nicer drive.
Peanut butter etc.

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