The Portland Bureau of Transportation wants to know if bike-friendly speed bumps are worth the trouble and treasure.
With an aim to slow down drivers and improve conditions for bicycle riders on neighborhood greenways, PBOT installed the first bike-friendly speed bumps (which they refer to as speed cushions) on SE Clinton street in 2017. The design includes two channels through the bumps that allow bicycle riders to roll through smoothly. Almost as soon as they hit the ground, the reviews from bike riders were very mixed. Some people love them, others say the channel is too narrow, can lead to crashes, and encourages drivers to swerve into them. Despite all that, PBOT has continued to use the not-yet-standard design citywide.
As we shared back in March, PBOT put out a survey to help determine whether or not they should continue to be part of the city’s traffic calming arsenal. The survey evaluated three things; rider preferences, the cost implications, and whether or not they actually reduced driving speeds.
PBOT Bicycle Coordinator Roger Geller brought results of the survey to the May 9th Bicycle Advisory Committee meeting and asked for feedback to inform a final report he’s working on.
Of the 540 survey respondents, 80% said they prefer riding through the channel. Geller also did observations at seven different locations and found a similar number of channel-choosers. “People are voting with their wheels. That tells me the channels create a more comfortable cycling environment,” Geller said at the BAC meeting. And since Portland city policy is to create the highest-quality cycling environment possible, Geller says these bike-friendly speed bumps are more closely aligned with city goals than conventional bumps.
When it comes to the accompanying pavement markings, most people who took the survey said they prefer a sharrow marking to be aligned with the channel. Geller says this is important for two key reasons: 1) the sharrow will lead riders toward the channel in dark or low-light conditions and 2) the sharrow will encourage people to ride closer to the center of the lane, which he believes is the safest choice when using a neighborhood greenway.
According to the city’s survey and evaluations thus far, the bike-friendly bumps and traditional speed bumps have about the same impact on lowering driver speeds. So if they seem preferable to most cyclists and they accomplish the traffic safety goal, why not close the case and make them a standard treatment?
Because they cost more. About 20% more on average according to PBOT estimates.
And bumps (of any sort) are likely to only go up in price since PBOT will contract out even more of them in the future. The majority of bumps in Portland are already installed by private contractors, and with PBOT’s budget in the hole, their maintenance crews are likely to do even fewer of them in years to come. Geller shared at the meeting that it costs PBOT crews about $2,500 to install a traditional speed bump and $4,000 to install a bike-friendly cushion. When they contract that work out, the price balloons to $7,000.
Add in the fact that PBOT must install more bike-friendly speed cushions to the get the same speed reducing impact as traditional bumps, and the cost goes up even more. A comparison of nine recently completed neighborhood greenway projects showed that PBOT installed 104 of the cushions when only 90 bumps would have been required — spending a total of $746,050 on the bike-friendly ones when they would have spent just $625,400 on bumps without channels. That’s a 19% difference.
When PBOT asked in their survey if a 10% cost increase for the bike-friendly speed cushions would still be worth it, 51% of people said yes. 40% of respondents said it would be smarter to save the money.
There was also grumbling from BAC meeting attendees that folks would rather have diverters instead of bumps. Geller acknowledged that bumps aren’t intended to reduce car volumes like diverters are, and he also said concrete diverters are much more expensive. (Keep in mind PBOT considers those round concrete barrels to be only temporary solutions and the more permanent treatment of a median diverter, including design and signage is estimated to coast around $30,000 a piece.)
When you factor in the cost issues and PBOT’s unprecedented budget crisis, I won’t be surprised if we don’t see any more of these bike-friendly speed cushions in Portland.
We should know their fate soon. Stay tuned for Geller’s final report.
Do the channels only help people on bikes, or do they also help fire / emergency vehicles? It seems that might change the math.
The emergency vehicle-friendly bumps are a separate thing. Typically those routes are not n’hood greenway routes and the fire-friendly bumps have a bit of a different design.
And SUV drivers. On many streets, they are able to cruise comfortably at 30+mph when this speedbump design is used. Try connecting from the Tillamook bikeway to the Halsey overpass on NE 92nd to see an extreme example firsthand. I never know if someone behind me is going to be doing 20mph or 50mph.
Funny how these “temporary solutions” have worked for decades in other cities that did not have a transportation bureau laser-focused on slow-walking* cheap and inexpensive ways to make neighborhood greenways attractive and safe.
*scoffing at the idea that neighborhood greenways should prioritize active transportation, burying inexpensive traffic calming under years of unnecessary outreach, requiring ridiculously expensive permanent installations etc.
And PDoT/ city’s public works department (PBoTs predecessor) also deployed concrete barrels and other precast object for diversion in the 1970s (or 80s/90s?) in the NW neighborhoods and these were in use for decades until recent capital projects had the budget priority to permanently fix the early/ mid century car centric intersection design flaws.
So with the current budget reality: CoP will need to revisit either using more precast (affordable) treatments [aka Quick Builds] or find the budget (political priority) to build in place treatments to address chronic traffic safety black spots / access barriers.
So worth it! (in my opinion) LOVE ‘EM!
that is hilarious! Did Geller say that? Delusional! PBOT exclusively designs bike infrastructure to be as good as it can be without a signal minor inconvenience to people driving or parking. Just please take a look at the north end of the Blumenauer Bridge and the obnoxious 90-degree s-curve across a sidewalk that bikes have to travel and tell me with a straight face the PBOT is creating the highest-quality cycling environment possible.
The obvious answer is the no bumps are best and cheapest- they don’t do much to control speed and they do nothing to control the dangerous presence of cars. Build NO bumps and use whatever money you have to build FUNCTIONAL diverters- not barrels or wands with 8′ gaps like Flanders.
If PBOT persists in building bumps, I think no gaps are better. The gaps are nicer, but they require precision. Since I am always sharing greenways cars, I sometimes get squeezed out of my preferred line of travel by them. I have encountered a bump while being close-passed and I ended up crossing the gap at an angle which is pretty sketchy at 15-20 mph. I think the hazard and cost is not worth the comfort.
The issue wasn’t the cutout, nearly everyone supports that, it’s that the cutout happens to be the width of a car’s wheels and they love to move towards the center of the lane to use them.
Make the cutouts further apart.
Eliminate the sharrows, which guide drivers to the center and merely indicate the obvious to cyclists. Eliminating them would also slightly reduce costs.
Sorry I missed this meeting and the detailed discussion. I am glad someone on BP answered the question as to if “no” speed cushions then would fire department not approve the use of ANY vertical deflection / traffic calming on this corridor type. (This was the case in Vancouver as to why we utilized speed cushions more often back in 2000 to 2009+…in order to get any traffic calming on routes that VFD had vetoed speed cushions on in the past (and future).
Jonathan, the other question I have is “why” are the speed cushion design(s) are “not yet standard design” for Portland?
Do you mean they are not in the city’s standard plans details?(I don’t have time today to look them up.) This treatment has been widely used for 20 years in the PNW region and other regions. See the links to the CoV details T02-23 to T02-25 bellow as an example…
CoV Transportation Details:
This is a great example of PBOT spending thousands of dollars to avoid inconveniencing motorists.
PBOT would rather spend $7k a couple of times each block on something that doesn’t work rather than install permanent traffic diverters once every four blocks, which are probably cheaper.
PBOT fundamentally sees greenways as being designed primarily for motorist speed and access. Until that changes, it’s a misappropriation of taxpayer money to even have the signs made.
Car drivers sure love to aim for them so they don’t have to slow down. Like what even is the point of having these little speed humps if drivers can just aim for the gaps? First time I saw them I figured it was just some new sort of concession to drivers that complained. Personally I’d prefer traffic diverters on greenways and not these speed humps that do little to slow down cars
I worked construction during college and observed road construction when I was an agency manager. I don’t see why the “friendly” speed bumps should cost an extra $1500. Materials cost the same; equipment should be the same. The difference must be in the time it takes for the crew to place the asphalt and feather the edges of the channels. Assuming a five-person crew, that suggests it takes an extra two hours to create the channels. Sorry, but it doesn’t add up for me. Maybe they just need more practice.
We don’t need speed bumps if there were diverters every 3 blocks on greenways.
I don’t think speed bumps are as big of an issue for cycling comfort as the actual pavement itself. The other day I saw a “bike friendly” speed bump with the pavement heaved, cracked, and totally uneven on the entire block the bump was on, including the channel in the speed bump. But yeah let’s blow 7k on SUV-friendly speed “cushions” I guess.