Speed bumps on Portland’s neighborhood greenways are a double-edged sword. They’re effective tools for slowing car traffic, making it safer and more comfortable to ride a bike on a street shared with cars. On the other hand, they can be unpleasant for people riding bikes to navigate over, adding some unfortunate nuisance to a bike trip on a greenway.
Then there are the ones with tire gaps.
When these types of speed bumps were first installed on the Clinton Street Greenway several years ago, they sparked a pretty heated debate. Are they for bikes specifically? Isn’t it less safe if drivers swerve to use them? Aren’t they only for emergency vehicles?
Recently, the issue came up again in the comments section of a BikePortland Instagram post about new bike-friendly speed bumps on NE Alameda. The consensus from naysayers seems to be that these gaps tempt drivers to dangerously shoot through them so they can avoid hitting the speed bump.
“I feel these encourage cars to veer from their lane and cause erratic, unpredictable behavior,” one commenter said.
“I watched no fewer than six people crash in a single Pedalpalooza ride when they haphazardly installed the NE 28th ones,” someone else wrote.
“I have always wondered how these are supposed to work. I have ridden my bike thru the dip but it put me towards the middle of the road and resulted in getting honked and yelled at by a car. Are they supposed to be for bikes to avoid the hump?”
Lots of questions. And a bit of confusion and concern. So we reached out to PBOT to find out what’s up…
According to the Portland Bureau of Transportation, there are two different types of speed bump gaps on Portland’s streets. The first were designed in response to complaints from emergency vehicle operators who said these traffic calming measures were slowing down emergency response times. These speed bump channels split the speed bump into multiple “cushions” narrow enough that a fire truck driver can bypass hitting the bump. The second type — the “bike-friendly gaps” — were developed later as a variation of the emergency response vehicle speed bump treatment.
“The fire-friendly speed bumps were created to slow people who speed on local and small collector streets without sacrificing emergency response time,” PBOT Public Information Officer Dylan Rivera said in an email to BikePortland. “Having received complaints from people biking about the speed bumps, dating back to when we first began installing them, we thought a different design with a channel in a different location could be a desired improvement for neighborhood greenways.”
Rivera said that so far, PBOT has had “good results on speed reduction” on the neighborhood greenways where they’ve installed these speed bumps
“Their intention is to provide a more convenient trip for cyclists, prioritizing their positioning on the road without sacrificing speed reduction,” Rivera said. “So these days, Portland has fire-friendly and bike-friendly speed bumps.”
I was personally surprised to discover how controversial these speed bump gaps are. I immediately noticed the treatment upon beginning to bike around Portland, and I always thought it was a nice idea. I invariably groan a bit whenever I have to roll over a speed bump (especially when on an e-bike with its higher speeds), so I’ll always aim for the gap if one is available.
I agree that too many car drivers swerve to use the gaps even though they aren’t supposed to. After all, speed bumps are installed to force drivers to slow down, and when so many of our streets were built to allow people in cars to go as fast as possible, this can be a hard pill for some people to swallow.
This is a tricky problem to solve. In my opinion, the solution isn’t to completely get rid of treatments like this. Instead, it needs to be more apparent to people driving that neighborhood greenways are meant to prioritize bicycling. This could be accomplished with more traffic diverters and signage that, hopefully, would change behavior over time and make greenways more comfortable and safer for people biking and using active transportation. Maybe one day, drivers will be so calm that speed bumps are no longer necessary!
Luckily for everyone who isn’t such a big fan of these “bike-friendly” speed bumps, it doesn’t look like PBOT will be installing them just everywhere yet.
“They’re not yet a standard tool. We are in the process of learning what we can, both about effectiveness and design,” Rivera said.
So, what do you think about the speed bump gaps? Are they helpful or do you think they just cause more problems?
Engineers have told me speed bumps are one of few tools that work, even with gaps. Drivers who manage to get one or (rarely) both wheels in the gap generally slow down to achieve that. So it’s functioning in part as a chicane. If true that’s fine—the goal is to prevent a high percentage of (especially the fastest) speeding, not the bump itself. With the large number of historic speed studies on PBOT’s Traffic Counts interactive map (see link) I suspect there are a bunch of examples of before/after data where bumps have been added that someone could compile if PBOT hasn’t done that. https://www.portland.gov/transportation/traffic-operations/how-we-gather-traffic-counts
That is a very typical engineer/PBOT-style answer. They do not design holistically. A speed bump is tool to reduce speed: add speed bumps. Speed bumps are uncomfortable for bikes: add gaps. Cars use gaps but still slow down: success.
There was time when PBOT had talented designers that would look at the creation of a Greenway as a chance to make a street safe and welcoming for people biking, jogging and biking. Of course traffic counts and speed were a factor, but they were not the only factor. Driver behavior and how that unpredictability would impact the experience of vulnerable road users were/should be issues that are thought through. NE 7th/Tillamook is a prefect example of PBOT using generic, cookie-cutter approaches and not doing thoughtful site-specific design. They took the most obvious solution to solve a problem, and made the street faster to drive on, added conflicts between cars/bikes, reduce pedestrian space and introduced new bike/ped conflicts.
PBOT recently had a couple of their designers leave.
I was the author of the crash comment, and I think one of the issues with these gaps is they usually accompany a removal of the centerline, which removes one barrier for drivers crossing the center of the road. As I mentioned yesterday, check out Harold street as a great example of most drivers zooming into the middle.
The other problem is they’re often implemented in a horrible fashion, making using the gaps unsafe for bicycle riders. Ride the ones on NE 28th near Burnside (where I witnessed multiple crashes) or Crystal Springs between 42nd and 29th to see what I mean. There’s leftover material making the gap unnavigable by bicycles.
I would say at best 1 in 10 drivers don’t aim for the gaps if there isn’t oncoming traffic and cyclists usually don’t count so the driver is passing way too close. The bumps themselves are pretty ineffective at slowing drivers down even when they do go over them. Large SUVs and trucks don’t seem to notice them. Even some smaller cars fly over them. At best I’d say it keeps people from flying down the street at 35+ which isn’t typically a problem on greenways.
PBOT has previously acknowledged the speed bumps on NE 28th Ave were improperly installed and the gaps were meant to be wider. Sadly, these have never been corrected and continue to be a hazard.
Speed bumps are never the answer and installing one is an admittance of street design failure.
Remove centerlines, add diverters, chicanes, narrow down the driving space, etc…
Ideally speedbumps would be bigger/hardened road features that truly slow vehicles down. They could have a huge steel bollard in the middle that only lowers to let emergency vehicles use the grooves. That might not always work right, though. Maybe the center is a mini concrete-curbed island that firetrucks can clear, but cars would be intimidated by? Guess it doesn’t matter if everyone’s driving a pickup truck/SUV?
I’m not sure what the best option is for bikes. With regular speedbumps I often sneak by along the curb, but sometimes it’s full of mystery debris. It’s nice when there’s a wider flat section along the edge, along with a raised curb to keep cars from driving onto the shoulder. The groove in the center of the lane, like these new “two groove” bumps is a nice option for biking, so long as cars aren’t swerving into the middle of the road.
The 28th three-grooved bumps are a bit narrow and seem like they’ve slumped in from the weight of bus & truck traffic. Narrow grooves make it difficult for cars to cut through on the flats, but bikes still can.
These bumps on SE Thorburn have the three grooves and are wider than the ones on 28th. PBOT added signs/posts on the outside to deter drivers from swerving onto the shoulder.
Of course some of the outer signs have been run over as you can see here:
6451 SE Thorburn St – Google Maps
I think two grooves is better than three. Two grooves causes vehicles to swerve into the center of the road, and into my lane. Three grooves means some people go “halfsies” and dip the drivers side/center wheels into the center lane groove. It’s less intimidating to do the center dip, so I see more of that behavior, even with oncoming traffic. With the two grooves people seem less likely to swerve that far towards oncoming traffic.
At least PBOT is trying something…?
Some of the gaps in the new “bike-friendly” speed bumps on the narrower streets are perfectly sized to allow cars to maintain their speed through the speed bump/gaps even without having to swerve. Seems like a bug and not necessarily a feature.
My suggestion is to only have one center gap for the “bike-friendly” bumps, particularly on narrower streets. While this may lead to the occasional conflict between on-coming bike riders, it will maintain the overall purpose of the speed bumps to slow down vehicle traffic and minimize potential swerving.
As an aside, my understanding is that emergency vehicle speed bump gaps came out of the CIty/PSU Transportation Class for a student’s project along NW Cornell.
They are not good. I’d much prefer real speed bumps than the wheel cut ones, for all the issues already mentioned by others in this article
While biking I MUCH prefer speed bumps WITH the gaps. So much smoother.
I prefer the gaps too. When no cars are coming from other direction, I drive through the gaps without having to bounce over them. And no, I’m not speeding through and actually going well under the speed limit. It’s the bumps I’m avoiding, not the speed limit of 20.
Seems like a reasonable approach on major streets, but they’re annoying on greenways and emergency response vehicles can use other streets – a benefit of having a grid with very few diverters.
Speed bumps on “greenways’ only exist because PBOT is adamant that motorists have access to use greenways as through streets to avoid congested arterial roads.
If PBOT was in anyway serious about their “greenways” being greenways, we’d have traffic diverters every three blocks. They cost lost and work better.
I’m comfortable enough aiming just past the edge of the bump and riding on the curb. Pretty much the worst case scenario is that you hit the bump anyway. Ending the bumps a little bit short of would add a 1-foot berth that would mean much more to people on bikes than a speeding driver.
We can’t make people bypass the bumps. Then again, we can’t make people cross the tracks at a right angle or stop in the middle of a lane to activate a green light, but we use paint to teach them anyway.
Maybe there are better solutions, but cycling is still going to be inherently ableist and this one costs nothing.
Real speed bumps, or at least larger more pronounced barriers should be required. I’ve also seen cars speed through traffic diverters (some of which are wide enough to accommodate emergency vehicles). It seems like PBOT has zero bicycle commuters on their staff. Not even gonna ask how much these speed bumps cost..
If the gaps are narrow like on 28th E Burnside, they are dangerous for cyclists when wet as the tires are generally on an uphill slope when crossing them. If they are wide so they are easy to pedal through then they are wide enough they don’t slow down cars at all.
They are a waste of money.
I was on the nice Tillamook greenway today where they installed them and watched 2 cars blatantly run stop signs in front of me.. The most minor enforcement would do more for safety than speed bumps on every street.
My favorite Strava segment is riding uphill on SE Harrison from SE 20th to SE 30th. It was ruined when the speed bumps were put in, sob. On the bright side, the reigning KOM will own the title forever.
Speed bumps kind of work maybe a bit but more than that they just suck. They suck for busses and emergency vehicles, and they suck for motorists and cyclists. I hate them whether I am driving or cycling and you bet I will cross the center line in my car to use the gaps if there is no oncoming traffic. OTOH, the gaps are often narrow to negotiate on a bicycle unless you have some pretty good handling skills and I have occasionally experienced pedal strike using them, which is dangerous. When PBOT installs them on a bike route I generally stop riding on that route. The speed bumps on SE Harrison between SE 20th and 26th (non-gap) were completely unnecessary after the diverters went in, and I’m sure there are other examples of this all over town. I’ve also heard complaints on BP before about speed bumps being incompatible with certain types of bikes including cargo bikes, which PBOT doesn’t seem to consider.
I prefer the gapped bumps just further east on Harrison to those non-gapped ones you described. Though, counterpoint, my toddler in his front-mounted bike seat LOVES the bumps and complains about them being gone after we go past the last one.
That is adorable!
Super good point about pedal strike. I’ve experienced that and was super shocked by it. Also, courtesy gaps do nothing for trikes or people with trailers, both bike vehicles that will experience the effects of the hump more than anyone in the cockpit of a two-wheeler.
I don’t understand:
The gaps seem like an utter failure for the confusion and unsafe practices they encourage.
Agreed on all counts, squareman.
But I think it is even worse.
Emergency vehicles: they have duallies and duallies don’t fit through any gap I have ever encountered in these speed tables.
Cars swerving to shoot them: Just like the diverted on Ankeny at 16th, the actual design abbot adopts undermines the ostensible purpose of the installation
Bike riders: you mind riding over them? Really? I have no suspension on my bike and I can’t say that riding over them, even downhill at full speed on Stark with a trailer, ever bothered me.
But the absolute worst waste of taxpayer speed table money is on the one-way Westbound block on Ankeny East of 32nd Ave. What was PBOT’s thinking putting one there? The road width between the two rows of parked cars as about one car width! Who is the intended audience?
My answer to the cyclist question is that it depends on what type of bike you are riding, some bikes handle the speed bumps much better than others (try riding an old Schwinn Stingray over them sometime, it’s an exercise in trust especially going downhill at speed), and the same goes for motor vehicles, which is why some motorists can fly over them and others slow down as intended.
Plus they ‘ravel’ at their tapered ends so if they are not maintained after a while a pretty good curb-like bump is introduced at the entry point. Off the top of my head that’s now the case on most of the bumps on SE Elliot in Ladds Addition, but I’ve seen it in other places also.
Commissioner Mapps should revive PBOT’s traffic calming division so that we have a toolkit for bumps, chicanes and narrowing that is funded, equitable, cohesive, and implemented.
thanks for the joke!
Bumps suck. There are better ways to do this!
I hate the bumps on my normal bike commute through Sellwood: there are no gaps, so I have to stand and stop pedaling so I don’t bang my 4$$, and then my ebike motor cuts out!
And when I’m driving, I have to slow down way below the speed limit, in order not to have the contents of my trunk/truck bed bang around. I’d have less ire for them if they were sized/graded to enforce the 20 mph speed limit. . . but they’re a hassle unless I’m going like 10 miles an hour. And then I have to hit the gas to get back up to 20mph for a block.
New motor cycle rider, while traveling down a street with a 30 mph limit I hit a speed bump at 20 mph and wrecked. Just some scrapes and bruises plus damage to the motorcycle but I got back in and had to clear another bump which again almost wrecked my bike.
Ironically the big heavy, jacked up trucks and SUVs that caused the majority of issues and are so dangerous to pedestrians cyclists and people in regular cars , drive over them at 40 mph just fine without slowing.
The most impressive car swerving over center line I’ve seen in on N. Fessenden. Neighborhood desperately wanted to control speeding and now they have lots of speeding while crossing the double yellow in a quick evasive maneuver.
This includes Tri-Met busses who do this swerve as a matter of course regardless of who is in the opposite lane. I wonder if PBOT requested any sort of proof from”emergency vehicle operators who said these traffic calming measures were slowing down emergency response times.” Like, was there a pilot study, open comment period, engagement with all stakeholders to examine these claims? Y’ know, the usual processes they simply must go through for any sort of “safety improvement” that actually slows cars down?
They need non-Newtonian speed bumps.
Taylor, thanks for digging into the topic of speed cushions as a counter measure.
Here is a bit of history for the younger / newer PNW residents readers…prior to 2000 the standard practice for PNW traffic calming was to NOT consider traffic calming any arterial roadway with vertical deflection, even raised crosswalks were “off the table” with Western States fire departments having a ‘veto power’ over traffic engineers and planners use of such. This started to change when planners etc. started to point out that most of the west’s emergency response calls were for traffic injuries and few structure fires (>20%). I had seen and used a tool similar to speed cushions in the Netherlands in the 90s…so I recommended to John Manix (my project staff partner / neighborhood traffic engineer at the time) that we pilot them as part of Vancouver’s SE Neighborhood Traffic Safety Plan and our discussions with the Vancouver Fire Department leadership on arterial traffic calming. After much trust building with VDF, trials with rubber cushions and a programmatic promise to make corridor fire access enhancements (balance calming with overall response times) they became an accepted tool in the tool box at the city. Our first installation of asphalt cushions was on then newly rebuilt complete street of East Evergreen Boulevard in Hudsons Bay. The earlier pilot with the [failed] rubber cushions was on Franklin Street in Hough. These were the first use in the PNW and concurrent in the US with early pilots in Sacramento CA (and Austin TX, my memory). PBoT (PDoT) staff came up to Vancouver officially to inspect our use of speed cushions in ~2005.
Can you speak to the gaps in them? I have to say I still am confused why they are there. Most are too narrow to be relevant to the duallies of emergency vehicles (fire trucks certainly), and given the propensity of everyone else (motorized and not apparently) to shoot the gaps, aren’t they (the gap feature) self-defeating?
9watts: Good question. The effective width was set wider than the typical passenger car but narrower to the typical axel width of a EMT / fire apparatus. Then the profile (steepness) of the bump is set to reflect a near maximum operating speed. This tool type was never intended to work on 100% of speeding vehicles but a super majority.
So if the speed cushions are not performing adequately to calm corridor travel speeds these things can be adjusted / evaluated:
– profile (check to see if built to specifications or are worn)
– frequency of placement (are they too far apart, European spacing was as frequent as 150 ft vs a more permissive application in US ~300 to ~900 ft spacing)
– can vehicles avoid them by leaving the through lane (add / replace supplemental horizontal deflection / controls)
– vehicle design (do too many vehicles have wide axels, freight trucks, F350 SUVs etc, if yes then supplement or remove and revisit tool selection.
the real solution is speed governors. Until we get them we will continue adding ridiculous things to make it less efficient and less comfortable to drive on neighborhood speeds at the expense of biking comfort. I can’t stand speed bumps but understand why they are there. It is especially jarring when biking with a newborn.
Yes! With all the interest and pushing for fully autonomous driving, and with so many cars in production today with built-in navigation, lane position assist, following distance assist, and so on, there is zero technical reason that manufacturers could not immediately start making cars with computer-controlled governors to keep every single new-model passenger car at or below speed limits. What is lacking is the political will to give the car industry a big middle finger in Washington.
Fail. If the goal is to slow cars down, the speed bumps should extend just as far as the car lanes. Make it clear where the bike lane ends & the car lanes begin.
But many speed bumps are on streets without separate bike lanes.
And on streets that do have separate bike lanes–but not physically separated–is it better to run the bump through the bike lane, or stop it and risk drivers swerving into the bike lane so their right wheels miss the bump? I don’t know the answer–I can see arguments both ways.
My point is that they should either be solid all the way across, or separated from the bike lane if they are going to have gaps. And it needs to be enforced.