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.
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
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
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?
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.
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.
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.
i really like the wider video format.
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.
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.
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?
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.