Tearlach61

I have a bike lane design question. Short and simple, what do people think of a protected bike lane that uses a rumble strip (continuous or intermittent) as a seperator between car traffic and a protected bike lane.

I am an engineer and I have two projects where the goal is to improve things for pedestrians and cyclists. Part of the direction I have received is to think "outside the box." I think part of the reason I was given these projected is because I bike to work and have done so my whole adult life.

My sense is that a bike lane while ok doesn't really provide adequate protection of the cyclist. I was in the Netherlands last year i was quite intrigued with how they do biking. I have great respect for their expertise in doing bike infrastructure.

I am also quite familiar with design guidance in this country and, as a cyclist, I have issues with it. For example, they tell you to either have a bike lane of whatever width or a separated path with at least 5 foot separation between the path and the street.

The problems with the seperated path are many: first off you are just asking for accidents at driveways and intersection. Secondly, pedestrians are inevitably going to use at path which has problems of its own.

Just scanning through the recent posts I find example of the flaws of both these concepts. A cyclist killed while riding a bike lane in St. Pete and a cyclist suffering a broken leg while riding on a sidewalk. I know a sidewalk is not a seperated path, but that is the type of accident you tend to see on a seperated bike path.

Which brings me to the protected bike lane. The protected bike lane is a bike lane with more than just a thin stripe between it and the car traffic. It puts you closer to the traffic which is better at intersections but also protects more like a seperated path. The separator can be a thicker stripe or series of markings, a low narrow curb, parked cars, or pilons. In the Netherlands, I typically saw what looked like a 2" curb. Portland is experimenting with them, using striping. Chicago is going with the pilons.

My question is: what about a rumble strip along with striping of some sort? The advantage I see is that it would allow easier winter maintenance than a curb or pilons and would provide more protection than a mere paint stripe. We did an internet search on the idea but the results were not all that encouraging.

Any comments would be greatly appreciated.

dynodonn 

Rumble strips are difficult for cyclists to cross, plus in residential areas, they probably would get paved over because of complaints of excessive noise, especially on turns where motorists might cut the corner. Locally, our DOT had to pave over a section of rumble strips just for that very reason.

Recycle

+1
The League of American Bicyclists, Adventure Cycling Association, Alliance for Biking and Walking and several other organizations are actively campaigning against the use of rumble strips on bike routes and explaining to DOTs the problems they create for cyclists. The typical rumble strips carved or ground into the pavement destablize cyclists who try to cross them.

Check with the Australian Bicycle Council Cycling Resource Center. Melbourne Austrailia has been experimenting with thermoplastic strips about 5mm high and 100mm wide to accentuate some bike lanes.https://www.cyclingresourcecentre.org...ane_monitoring
They posted the results of a cyclist evaluation of the strips : https://www.cyclingresourcecentre.org...ane_monitoring

It appears that the thermoplastic strips do not present the same problems for cyclists that carved rumble strips do. I suppose they could be installed directly on top of bike lane stripes.

WickedThump

Rumble strips cannot be used anywhere snow may have to be plowed, much like the dots.

DX-MAN

Hmm, snowplows..... Guess I have a different mental picture of 'rumble strips'. Where they are on my commute route, they are a series of cuts, depressions in the pavement, not raised above it. They definitely get your attention when you roll over them! They are just outside the right lane, on the shoulder, and my kids LOVE riding over them (I only let them after traffic has passed).

I've seen a lot of resistance to the rumble-strip idea in various places; here, no one even knew they were being put in! As far as 'destabilizing' a rider, well. . . I have a hard time with that, it suggests to me that these riders aren't paying attention to surface conditions.

mconlonx

Rumble-strips anywhere near cycling specific infrastructure = bad idea.

unterhausen

rumble strips are just a way for road-raging motorists to threaten people in the bike lane. I'm pretty sure a trucker did that to me on a rural highway just this week.

sm1960

A possible solution would be to put the bike line between the parked cars and the sidewalk. I've seen this somewhere before, when looking at it it made perfect sense. The parked cars provide a barrier, although intersections would be tricky.

chandltp

And passenger doors would be tricky too. The cyclist would have no where to go to avoid an open door.

sggoodri

Invariably, the area to the right of the rumble strips becomes too strewn with debris to ride there with road bike tires. The only area of paved shoulders I normally ride is the exact spot highway engineers end up installing rumble strips; as a result I use the general purpose travel lanes on most roads I've experienced with rumble strips.

Any surface or raised structure that can cause a bicyclist to lose control is a definite no-no for bicycling facilities. Never use curbs, posts or other raised hazards between a bicycle lane and the general purpose travel lanes, as these are more likely to cause injury to bicyclists than the occasional drunk or distracted driver, and they create obstacles for bicyclists trying to leave the bicycle lane for their own safety or destination access.

rydabent

Personally I like rumble strips if they leave enough shoulder for a cyclist to ride on. Some places they make the rumble strips too wide and dont leave enough room to ride.

The reason I like them is that in some cases (texting while driving) where a driver starts to run off the road it is an audible indication to me to take to the ditch.

Tearlach61

Thanks for the responses. Granted you wouldn't want to cross the rumble strip, that's why I said possibly discontinuous. Also I'd discontinue them anyplace you'd discontinue a curb or pilons or anything else.

My big challenge is winter maintenace. Choose the wrong treatment and winter maintenance will go out the window. Ideally, you want to be able to plow the bike lane at the same time as either the sidewalk or the street. Anything that would force the bike lane to be plowed on a separate pass would make it difficult to keep it maintained in winter.

The road in question goes through an area where there is residential development on both side, plus commercial and some industrial. There is a junior high school near by. Kids have to cross the road to get to the hospital. There is an accident history.

The original road was: 6, 12, 12, 12, 6, shoulder, drive lane, continuous center turn lane, drive lane, shoulder. On one side, a sidewalk was retrofitted at one point in the past and the shoulder on that side is now 4.5 feet. The road is built for speed. Speed limit is 40 mph, volume of traffic is 12,000. Over a 1 mile stretch, there is exactly 3 cross walks. The stretch of road has an accident history with peds. There is a guy at work who was right hooked not long ago riding through this corridor.

Like I say, I'd like to get something a little more substantial on the table than a simple striped bike lane. We want to slow the traffic down and a paint stripe won't help much in that regard.

Doohickie

If one were to use rumble strips, they should indeed be discontinuous.

Personally, my very favorite form of bike infrastructure is a very wide right lane, essentially two lanes wide, but with no lane markings, just sharrow markings. The advantage is this: cars will occasionally but infrequently drive on the right portion of the lane and "sweep" debris from the lane that would hamper cyclists. When a cyclist is present, there is plenty of room for a motorist to pass. If there are lane markings, cars almost never cross over into the bike lane, but instead push all the debris from the traffic lane into the bike lane, resulting in all kinds of debris in the bike lane.

dynodonn 

+1

There's as section on my commute that has a portion with bike lanes, the other portion with sharrows marked at least to the 11 foot standard, and the sharrow is always swept by traffic, the bike lanes are constantly filled with debris. Plus in the sharrow section, I can take the lane with far less harassment from motorists than when I leave the bike lane.

unterhausen

slowing down the traffic is the real trick, isn't it? I don't think that rumble strips are a good way to slow down traffic. Marginally better than striping bike lanes, no doubt. I think the only thing that really has been shown to slow down traffic is narrow lanes, trees, well-constructed traffic tables, traffic furniture and traffic circles. And even then, people don't always slow down. Thinking out of the box is great, but it often leads to failed experiments. I have seen mention that separated bike lanes using barriers have a less than stellar history.

They just went nuts putting down rumble strips around here. They took a batch of them back out after the cycling advocacy group complained.

sanitycheck

We've got a short section like this in my town. It's not a good thing. Intersections are worse than just "tricky", especially since every driveway constitutes an intersection. You've got almost no visibility to drivers who are about to turn into those driveways (often without bothering to signal, since they figure there's "no other traffic nearby".) At night it's worse; unless you're wearing front and rear helmet lights, the parked cars obscure your lights from drivers altogether.

And chanditp already pointed out the door zone problems.

Ordinarily I would just assume the lane was a traffic engineer's idea of a joke, and use the main travel lane instead. But this one is a contraflow lane on a one-way street, and while only a block or two long, provides the only access to a very useful bike/pedestrian freeway overpass. So I just slow way down and treat it like an even dicier variant of sidewalk riding, always assuming that any car could make a blind, unsignaled lurch for a driveway at any moment. If in doubt, I get off the bike and walk. It's not a huge problem since it's only a couple blocks, and access to that overpass is very nice, but I certainly wouldn't want the town to design more lanes like that one.

degnaw

In Stockholm, on roads with on-street bike lanes (generally dense, lower speed urban areas), they do use rumble strips of sorts as the demarcating line - the paint of the dotted demarcating line is raised slightly, enough to jar me quite a bit on my 23c road bike. And they certainly do get snow here, though I'm not exactly sure how the lanes are dealt with.

squirtdad

The majority of the world does not have the faintest idea of what a sharrow is. The problem is that if you do not know what the sharrow marking means, the markings in and of themselves do not clearly establish their meaning. Bike lanes on the other hand clearly establish their meaning.

The bike lane to the right of parked cars has issues with pedestrians and every one else using it and makes intersection more dangerous.

I am of the opinion that bikes lanes provide the most effectinve combination of meaning, understanding and cost. Of course bike lanes vary in size, placement and quality if you will. So a focus on wide lanes, with addtional street signage to cover winter when marking may be obscured would be a workable solution.

himespau 

That 12' lane sounds wide enough for sharrows as it is. Might give that at try for starters at the cost of only some paint and road worker's time and see how that goes.

Doohickie

There is that, too.

It's pretty obvious even if you've never seen them before. It means "bikes can ride in this lane." Typically, our city also posts Bikes May Use Full Lane signs along with sharrows, at least on busier streets (they just post bike route signs on light traffic residential streets).

The problem with bike lanes, even here in Fort Worth where they seem to really try to get it right, is that they constrain a cyclist to a certain zone of the road. Sometimes that puts a cyclist in a door zone, almost always it is an area of debris accumulation. And you are right in that bike lanes provide meaning and understanding. The meaning they convey to motorists, unfortunately, is "Cyclists must ride there and do not belong in a motor traffic lane."

When putting in new bike routes around here, if there is ample room to accommodate a safe bike lane, they put that in. If there isn't enough room for a bike lane, they do sharrows with the Bikes May Use Full Lane sign. Some of the older city streets vary from block to block in terms of width, so even on a continuous route it may switch back and forth from dedicated bike lane to sharrows.

Recently the city planner in charge of cycling and walking infrastructure has started riding with our riding group (the Night Riders), so she's getting practical experience in the infrastructure she's setting up.

merlinextraligh

There are bike lanes in Florida with rumble strips,and they're a PITA to ride on, particularly with a group.

What I 've seen that works better is double lines about 12" apart, creating a buffer between the traffic and the bike lane.

Then you can either mark the lines with raised reflectors, spaced far enough apart for cyclists to move through, or chevrons between the lines done with raised paint. Either one of those gives auditory feedback to an encroaching driver, but aren't a problem for cyclists to ride around.

genec

Raised anything doesn't work in an area with snow... plows just remove that raised stuff. Rumble strips designed for bikes do work... provided they also have gaps just like those raised reflectors.

ItsJustMe

Rumble strips are heavily used here in Michigan and I promise you that we have plenty of snow to plow.

sggoodri

A three lane road with paved shoulders is about as good at it gets for cycling on 12000 ADT roads where I live. Drivers can use the center lane to pass cyclists who use the travel lane, and cyclists have the option of using the shoulder if they want. I cycled for years on a fairly busy 3-lane 45 mph road with an unusable shoulder and didn't have any problems.

What is the bicyclist crash history on this road? You mention a near right hook; nothing you do to the shoulder, short of eliminating it, will prevent right hooks if cyclists are choosing to ride on the shoulder at intersections and driveways.

If the concern is pedestrians crossing 3 lanes, then add median refuge islands at important crossing areas. Alternatively, a full length raised and landscaped median with left turn pockets at intersections will calm traffic and reduce pedestrian crossing collisions. Using mini-roundabouts at intersections will calm traffic even more.

Looigi

I haven't read all the above posts in their entirety so what I say may be redundant, but....

A low curb does little stop cars but is very hazardous to cyclists, potentiating falls into the traffic lane.

Rumble strips created by grinding depressions into the road surface are compatible with snow plowing and can be found in many places in snow zones like New England, CO, etc...

Some of the rumble strips have depressions that are deep and long enough, and sharp edged enough, to be extremely jarring to a rider, again potentiating a fall or a pinch flat.

IMO, anything that impedes the ability a cyclist to move over into the traffic lane if necessary is potentially unsafe.

The only thing that will stop a car from going into the cycling lane and the cyclist from falling into the traffic lane is a high wall.

Finally, I'd like to see somewhat less money spent on cycling infrastructure of limited extend and dubious value and more on driver education and awareness programs, like billboards, PSAs, etc.. The biggest problem I have is the ignorant driver, and I run into a good number on every ride. They either think the cyclist has no place on or any rigths to the road, or that they have to go to ridiculous and unsafe lengths to yield to cyclists....like I'm stopped at a stop sign on a minor road waiting for a brake in traffic to cross a major artery and a driver slams on their brakes and comes to a stop nearly getting rear ended and causing a chain reaction behind them. Or me sitting at a red light and a car with the green stopped and motioning me through. Sheesh. Simply knowing to treat bicycles as they would other vehicles would go a long way.