Apr 262012

Typical bumpout

Curb extensions or “bumpouts” are a common method of calming traffic and shortening the street crossing distance for pedestrians.  The idea is that narrowing the roadway slows traffic by reducing the maximum safe speed as perceived by drivers.  Center islands serve a similar purpose.

Unfortunately bumpouts often obstruct the space to the right of the travel lanes that’s used by bicyclists.  It forces cyclists to wait for traffic before passing the obstruction.  Even worse, drivers may misjudge the distance or the width and try to beat a cyclist to the bumpout when it’s not safe to do so.  This seems especially likely when the shoulder narrows gradually instead of suddenly.  I was almost run off the road on Arcola Avenue once, where center islands are used in place of bumpouts and the shoulder tapers to nothing before each island.  The driver seemed intent on maintaining his speed,  even though I was reaching the gap before him.

The county has started implementing two types of bumpouts that let cyclists avoid or evade these structures:

1. Create ramps that let the cyclist ride up and over the bumpout.  This is the solution applied on Fairland Road west of Old Columbia Pike.  A variation of this uses a path that runs up onto the grassy area and back down, seen on Calverton Blvd.

Fairland Road "up and over" solution

Calverton Blvd "up and over" (or "up and around") solution

2. Provide a street-level gap in the bumpout.  This turns the bumpout into an island.  Castle Boulevard off of Briggs Chaney Road uses this configuration.

Castle Blvd "slot" solution

Castle Blvd slot with center island

Castle Blvd slot next to bus stop and poor pavement

Below is a variation on the slot solution used when there are just posts instead of a concrete bumpout, as on Layhill Road.  The bike lane goes through the gap in the posts.  I kind of like this better than concrete bumpouts.

Layhill Road with posts instead of a bumpout. Bike lane goes through the gap.

Here are a few other possible solutions:

  • Giving cyclists the right-of-way.  This is a creative but very non-standard solution.  The bike lane would go around the bumpout on the left, into the travel lane where it’s not wide enough for a car to pass a bike.  Since half the lane width at the bumpout would be occupied by the bike lane, drivers would have to wait for the cyclist to go through first.  In other words, drivers would have to merge with cyclists rather than the other way around (or maybe an alternating merge could be required like on some highway ramps).  It would be essential to have pavement striping that makes this clear.
  • Sharrows telling bicyclists to temporarily share the lane at the bumpout, as seen here.  When the bump-out blocks the bike space, bicyclists are advised by sharrows and possibly signs to merge into the travel lane.  Sharrows let drivers know that this is not a strange event.  This really isn’t a solution, just a mitigation of a difficult situation.

The best solution

Can’t we just make the bumpouts smaller?  I realize that there are trade-offs between pedestrian safety and bicyclist safety, which may depend on many factors including the type of road, traffic speeds and the number of pedestrians and bicyclists.  Consider also that pedestrians can be put at risk by bicyclists riding over or through bumpouts.  Generally I think smaller bumpouts are the right solution whenever there are marked bike lanes or lots of bike traffic, like this:

A smaller, friendlier bumpout

But otherwise I slightly prefer the up-and-over configuration, though it’s not a strong preference.  A lot of it may depend on the context.

On the part of Fairland Road that I rode, the up-and-over ramps provided a smooth enough transition and I didn’t feel like I had to slow down too much.  And because the pavement was elevated, debris didn’t collect there.

But when riding on Castle Blvd I felt like I really had to slow down because I was riding through a narrow gap flanked by curbs on both sides.  I was especially unnerved by pedestrians standing on the sidewalk right next to the bumpout.  Anywhere there are lots of pedestrians, and especially where there are crosswalks, I could see people walking out into the bike slot without a clue.  It’s also not uncommon for bus stops to be located at crosswalks, so pedestrians might collect there (as I saw them do on Castle).  Fairland Road might have seemed misleadingly better in that regard because few pedestrians use that road.  Pedestrians might literally stand in the way on Fairland since the bike ramps look like sidewalks.

As for the details, the up-and-over solution as implemented on Fairland is also not very attractive and seems improvised.  There surely must be more appealing and more standard ways to implement it.  As for debris, the bumpout slots on Castle were relatively free of it, but it wasn’t easy to tell from a distance, and on many roads I could see this as being a real problem.

For whatever reason, parked cars in the shoulder don’t seem to be as hazardous as bumpouts.  I believe it’s easier for both drivers and cyclists to judge the distance to parked cars, and they really stand out.  I personally think drivers take some pity on cyclists who have a parked car in their way.  I’m often waved through by drivers.  But when the shoulder physically narrows, I swear drivers think it’s my fault.

Montgomery County DOT is looking to know if these designs are acceptable.  Opinions are welcome.

  7 Responses to “Dealing with curb bumpouts”

  1. I do see debris as a problem for these. A few snowy winters with sand trucks throwing sand and salt on the roads, plows throwing dirty snow onto them, plus cars spreading dirt off to the sides, coupled with no way for a street sweeper to reach these areas, and before you know it, there will be a ton of dirt and gravel on them and no way to clear them.

    Personally, I dislike bump outs of any stripe. At crosswalks, they merely give motorists more opportunity to disregard the law by failing to yield to pedestrians in the crosswalk since they give the illusion that the pedestrian is safely tucked behind curbs.

  2. In my view, bump outs you cannot ride over are a significant safety hazard, at least in dense areas where there is a lot going on. While there are many adequate ways to accomodate cyclists into the design, in no case should bump outs be designed to cause a cyclist to endo if he/she hits one accidentally. It’s hard to even imagine planners ignoring drivers’ safety to the extent that would cause them to construct bump outs using jersey barriers. But that’s pretty much what a veritical curb across the roadway is to a cyclist.

  3. I wonder if it would help if the slot between the island/bumpout and the curb were wider. I’m not sure there’s room for that however.

    • I agree with Jack in narrower island would be better.
      1st choice however is to narrow from the right and leave a 5 foot marked bike lane next to the travel lane. However these bumpouts are supposed to help pedestrians navigate faster traffic crossings.

      Personally, I very much dislike the Fairland Road ‘speed bump’ for bicycle bumpouts. I ride this periodically – they are mostly tied to bus stops – and thus appear to peds as part of the bus stop waiting area – so peds think they should/can stand there. They present a drop-off hazard if you have to move left to avoid a ped since there is a ‘clff’ like a regular curbcut.

      best choice – no bumpouts at all but in decending order if something is to be done
      1st choice – bumpouts leaving a bike lane width.
      2nd choice – narrower pavement islands
      3rd choice – Castle Blvd design as is – with a promise of regular sweeping
      4th choice – Fairland Road speedbump design
      5th choice – bollards stuck in between the travel lane and the shoulder

      not a viable option – as done on Old Baltimore Rd (Olney), Kemp Mill Rd (Wheaton) – bumpouts that occupy the entire shoulder forcing cyclists into the travel lane with the cars at random intervals.

  4. Delaware has a number of bumpouts (eg. Augustine Cutoff) like your Castle road photos. In the winter, this makes the shoulder completely impassable since they are not plowed. I also find they collect leaves in the fall. If these bumpouts are installed, I’d suggest sharrows and “Bicyces May Use Full Lane” signs. (DE state restrictions on their use effectively eliminate them on DE state roads.)

  5. (It’s the sharrows and Use Full Lane signs that DE eliminates, not the bumpouts – the bumpouts are used in a number of locations)

    • That’s too bad the Delaware doesn’t like BMUFL signs. We’ve finally gotten approval for them here in Maryland. We’ll see how often the state uses them in practice, but counties tend to follow state policy so it has good ripple effects.

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