Walkable West Palm Beach

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Future of the Palm Beach Lakes Boulevard Bridge

As part of the one penny infrastructure sales tax surcharge, Palm Beach County will rehabilitate the overpass of Palm Beach Lakes Boulevard over the Florida East Railroad (overpass). On April 4th, Palm Beach County will allocate the one penny sales tax to specific projects. At this time, the County hasn’t shared their proposal for the overpass. This post will explore the history of the overpass and provide a design concept that would be an asset for the adjacent properties instead of a liability.


Aerial shot of overpass


Prior to the overpass construction, Palm Beach Lakes Blvd. was named 12th Street. 12th Street was a local neighborhood street that dead ended at the railroad. An aerial photo of the future overpass location shows on-street parking at the corner of Sapodilla and 12th St. for the corner store. The photo also shows the majority of lots along 12th St. with structures.


This is a Sanborn map from 1952 of 12th St. in the location of the future overpass. Again, note the number of buildings on 12th St.


The existing overpass was constructed in 1965 by the City of West Palm Beach. In order to create space for the travel lanes on the overpass, on-street parking on 12th St. was eliminated and access to 12th St. was maintained via one-way frontage roads.

Today the majority of properties next to the overpass are now vacant.


Today pedestrians and cyclists must traverse a desolate area under the bridge to utilize ramps to cross the railroad tracks.


Pedestrian ramp tower to top of bridge to cross railroad tracks


Pedestrian ramp tower to top of bridge to cross railroad tracks

Clearly, the existing pedestrian and bicycle facilities aren’t acceptable.


There is a better way. Bridges don’t have to be utilitarian structures. They can have planters, trees, benches, and shade structures. The following are all bridges:


Pfluger Bridge Austin


New York, New York High Line


Long Street, Columbus Ohio


If the frontage roads were eliminated and access to the adjacent properties was provided from the alleys, then 80′ is available for the bridge. The current roadway could be reduced from four to three lanes. Two lanes would be provided in the eastbound direction and one lane would be provided in the westbound direction. Pedestrian and cyclists would be provided with a wide pathway to cross the railroad tracks on top of the bridge instead of walking under the bridge. Large landscaped buffers would be provided between the vehicles and the multimodal paths.


Proposed Palm Beach Lakes Boulevard Overpass

Bridges are a long term investment so it is important to get the design right with proper community input. This bridge will be with us a long time and a good design can set the stage for reinvestment, whereas a poor design would be unalterable for another 75 years. Nearby institutions such as Good Samaritan hospital could eventually have the need to expand into new space and the vacant land adjacent to the bridge could be developed under this concept. This concept would make the best of this overpass by making it crossable and comfortable on foot or on bike, and it would be supportive of future development along it when the time is right.

Here’s how it would work. The fourth floor of a building abutting the overpass would be at the same height as the highest point of the bridge.  As shown in the following section, the bridge section would provide for a connection to the future buildings. To those walking or biking on the overpass, the overpass would appear not as an overpass, but rather as a normal street. The overpass would connect to the adjacent land uses and no longer divide them. Imagine healthcare workers living within a five-minute walk of a major employment center. A hospital expansion or medical offices (as examples) could be part of the fabric of the neighborhood, rather than an isolated campus.


Proposed overpass section with abutting five-story buildings

Granted this is an ambitious proposal for the bridge, but it would be an investment in our future. At this time the County hasn’t released its plan for the bridge and this is only one of many options for the overpass. The idea proposed would need to be vetted and gain the support of the neighborhoods adjacent to the project. The purpose of this proposal is to initiate a conversation about neighborhood needs and design options; at a bare minimum, pedestrians and bicycle riders require a safe and comfortable crossing over this overpass. Please, leave your thoughts for the future of the overpass in the comment section.

If you would like to see your sales tax dollars spent to make a great overpass, then you should contact your Palm Beach County Commissioner.


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Ramblas and other center of roadway configurations in the real world

The City is currently studying enhancements to North Broadway from 25th to 42nd St.. One idea that that has been proposed by the City is to convert the center of the road to a promenade / ramblas configuration with a multi-modal pathway and parking in the center. This post will provide precedents for this concept. In a follow up post we will explore some of the advantages of this configuration.

When we think of complete streets we usually think that parking and bike facilities are located on the outside of the street and cars have use of the middle of the street.  As shown in the below examples the middle of street can be used for things other than cars. Bikes, parking, cycle tracks, public plazas or any combination can be accommodated in the middle of the street.


Tree lined multimodal path in the median of downtown Winter Garden, Fl:

Queens Plaza North, New York, New York

Streetfilms Queens Plaza

Sands St. in Brooklyn New York

Streetfilms Sands St.

Pennsylvania Avenue in Washington, DC

Streetfilms Pennsyvania Ave. story with Gabe Klein


Strandvägen Stockholm, Sweden

Erik Dahlbergsgatan Stockholm, Sweden

Bike and pedestrian

Place d’Anvers, Paris

Boulevard de Rochechouart, Paris

Allen Street New York, New York (recent project, street view has great before and after views)

Place making

Passeig del Born, Barcelona, Spain

Rambla de Catalunya Barcelona, Catalonia

Paseo del Prado, Havana, Cuba

Middle of the street used for parking

Clematis St. West Palm Beach


Clematis Avenue, Looking West from the Palms Hotel State Archives of Florida, Florida Memory, http://floridamemory.com/items/show/152572

Lancaster Blvd, Lancaster CA

Hollywood, Florida




Nine foot travel lanes in practice

When it comes to lane width, less is more.

This post explores a state highway section with 9 foot travel lanes, and will demonstrate that in spite of transportation agency misgivings about narrow lanes, Forest Hill Boulevard performs better on crash statistics than FDOT guidance for similar roadways, while offering advantages in the form of reduced construction costs, less negative impacts to adjacent properties, and decreased stormwater runoff, among other positive benefits.

Forest Hill Boulevard - West Palm Beach

Forest Hill Boulevard – West Palm Beach

Transportation agencies routinely make arguments against roadways such as Forest Hill Blvd. that are not based on studies or facts, but rather are based on conjecture of what might happen if narrower than standard lane widths were utilized. Since Forest Hill Boulevard is a real road in the real world it provides an opportunity to observe 9′ lanes in practice and not conjecture.

Livable streets advocates often recommend the use of 9′ to 10′ wide travel lanes instead of wider 11′ to 12′ lanes for several reasons, including:

  • Lower construction costs
  • Less right of way acquisition required
  • Decreased stormwater runoff
  • Lower maintenance costs
  • Lower travel speeds and less injurious crashes
  • Smaller footprint which can allow limited right of way to be reallocated to other uses such as on-street parking, bike lanes, or landscaping.

Even with all of the advantages of narrower travel lanes it is often impossible to have transportation agencies allow the implementation of narrower travel lanes. The FHWA summarizes the potential adverse impacts to safety and operations for a design exception for lane width as follows:

  • Sideswipe (same direction) crashes
  • Reduced free-flow speeds
  • Large vehicles off-tracking into adjacent lane or shoulder

Jeff Speck’s article, “Why 12-Foot Traffic Lanes are Disastrous for Safety and Must Be Replaced Now“, provides a strong case for why reduced free-flow speeds are desirous and how narrower lanes help to achieve lower speeds and safer streets:

Forest Hill Boulevard Details

Our case study is the section of Forest Hill Boulevard (SR 882) in West Palm Beach between I-95 and S. Dixie Highway. This section of road has five lanes and is classified as an urban minor arterial with an AADT that varies from 28,000 at the western end near the I-95 interchange to 17,000 at the eastern end near S. Dixie Highway.

In spite of the 17,000 to 28,000 vehicles passing by each day on the road the walk on the sidewalk is relatively pleasant. The trees provide much-needed shade on hot Florida days and also a feeling of safety from errant vehicles.



The sidewalk and a wide tree-lined landscaped buffer frame 48′ of asphalt located between the curbs. As shown in the below section from FDOT, Forest Hill Blvd. was proposed to be resurfaced with 9′ wide lanes and a 9.5 wide center turn lane.

Forest Hill Blvd. - FDOT section

Forest Hill Blvd. – FDOT section

It seemed unbelievable that Forest Hill Blvd. had 9′ lanes so Walkable West Palm Beach field investigators measured the lane widths to verify.


Walkable WPB confirmed the 48′ curb to curb dimension, but, as shown in the below section, there were a few minor variations in the lane and shoulder widths compared to the FDOT drawing. Forest Hill Blvd. has 9′ wide inside travel lanes located between narrow, by highway standards, adjacent lanes.


How do roads such as Forest Hill Boulevard compare from a traffic flow and traffic safety standpoint to a similar 5 lane road with 11′ to 12′ lanes? There isn’t much information on the performance of 9′ lanes, but by reviewing the data on 10′ wide lanes we may be able to glean some insight. In Jeff Speck’s article he states that there are very few studies on the issue of 10′ wide lanes, but the few studies that do exist support the theory that 10′ lanes are as safe or safer than 12′ wide lanes and have the same vehicular capacity.

An analysis of crash data obtained by Walkable WPB from FDOT for Forest Hill Boulevard also supports the theory that narrow lanes are as safe as wider lanes. For the 0.787 mile portion of Forest Hill Boulevard just east of the I-95 interchange to S. Dixie Highway there were 60 crashes from January 1, 2011 to December 31, 2013. From this data a crash rate of 3.094 crashes per Million Vehicle Miles (MVM) is calculated by averaging the 17,000 and 28,000 AADT counts. 60/[(22,500 vehicles per day X 365 days a year X 3 years X 0.787 miles)/1,000,000]

This crash rate is less than the average crash rate provided by FDOT. FDOT provided the following information on average crash rates via email:

The average crash rate for 4-5 lane urban divided roadways with painted/paved median for the 2011-2013 period For FDOT Managing District number 4, which includes Palm Beach, Martin, Indian River, St Lucie and Broward Counties, is 3.719 crashes per MVM.

The FDOT crash data for Forest Hill Boulevard is available for download here.

Buses are cited as a reason to not utilize lanes narrower than 11′. Forest Hill Boulevard has bus service.

[10/12 4 pm edit –  We’ve been asked about the outer lane the bus is traveling in. The outer lane is actually 8.5 feet in width, with a 1.5 foot shoulder. So if you include the shoulder with the lane width, the bus is operating in a 10 foot lane. If you do not, the bus is operating in a 8.5 foot lane.]​


A few feet reduction in lane width can have a huge change in appearance of a road. Below is a photo of a five lane road in Palm Beach County that meets the standards.

Gun Club Road West Palm Beach Florida

Gun Club Road West Palm Beach Florida

…contrasted with our study section of Forest Hill Boulevard

Forest Hill Boulevard - West Palm Beach

Forest Hill Boulevard – West Palm Beach

The first photo of the standard five lane road provides a 3′ shoulder, 11′ lanes, and 12′ center turn lanes for a total of 62′ of asphalt. Note, the lack of trees because there isn’t room for them. Forest Hill Boulevard only requires 48′ of asphalt for the same five lanes of traffic. The difference between the two roads is dramatic.

On which of these would you rather take a walk or own a home?

The Forest Hill Boulevard section is more nuanced and contextually sensitive to the area where it is located. Designing a street section for an urban environment involves tradeoffs. We must avoid the tyranny of specialists who demand that we design roads to optimize only one outcome for one mode of transportation at the expense of other modes. The “standard” five lane road shown with 62′ of asphalt optimizes auto comfort at the expense of higher maintenance costs, greater stormwater runoff, less comfort for pedestrians, and lower property values. A question that engineers and the public should be asking is if the benefits that wider lanes provide for automobiles outweigh the costs. Does the design make sense for the context in which it is located?

Many of the improvements recommended in the Jeff Speck West Palm Beach Walkability study require that FDOT roads in West Palm Beach have their lanes reduced to a 10′ width. While FDOT has switched from 12′ to 11′ lanes in urban areas there is still significant resistance to adopting lanes narrower than 11′ in width. For those that are frustrated at the continued reluctance to utilize 10′ lanes a quote by the German philosopher, Arthur Schopenhauer, may provide some comfort:

All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.

Given the Forest Hill precedent that 9′ lanes work in an urban environment then what logical argument is left to deny the use of 10′ lanes in low speed urban roads? Even the Federal Highway Administration is endorsing context sensitive design on streets designed for speeds less than 50 mph. From Streetsblog:

The one-size-fits-all approach to street design has been propagated, in part, by federal standards that apply to a surprisingly large number of urban streets. But not for much longer. In what appears to be a major breakthrough, yesterday the Federal Highway Administration proposed rule changes that will allow cities and towns to more easily design streets in a way that’s consistent with an urban setting.

Bill Schultheiss, an engineer with the Toole Design Group, said the changes are welcome news.

“We need to move away from cookie cutter, cut-and-paste designs and allow engineers to be the creative problem solvers that most of us naturally are,” he said. “This is a tremendous change of direction by FHWA that needs our support.”

It’s worth noting this is a relatively busy minor arterial, according to its FDOT classification. Of course, low volume neighborhood streets can be even skinnier still.

Big Asphalt and the Bigger Takeaway

The American transportation model operates under the belief that if some asphalt is good, more is even better. Wider roads drive positive economic indicators, so the theory goes: More asphalt = more growth, more jobs, more tax base.

Forest Hill Boulevard demonstrates there is a point of diminishing returns to this approach and at some point roadway expansions do not increase our prosperity, but rather decrease it (I highly recommend watching Urban3’s analysis of Palm Beach County property tax productivity for the evidence). Our national obsession with short term growth manifests itself in public malinvestment in highways; repeat this same scenario one million times over and you start to find some answers for why we’re having trouble paying for basic infrastructure maintenance despite decades of robust economic growth post WWII.

If you’re interested in changing things, Strong Towns is an organization working hard to get us back on a path of a fiscally sound development pattern and sustainable transportation funding. Here’s a great place to start the conversation.

Urban3 tax productivity analysis of Palm Beach County



S. Dixie Highway Road Diet

On Saturday March 28 the Treasure Coast Planning Council held a public design workshop for the section of South Dixie Highway from Albemarle Road north to Okeechobee Blvd. On everyone’s mind was a road diet for this section of South Dixie Highway. The default road diet in these situations is to convert the existing four lane section to a three lane section with parallel parking on both sides. This is a tried and true method and it would be a fantastic improvement.

However, there is an alternate design that should be considered. The inspiration for the alternate design was a postcard of Clematis Street in the early 1900s with a single row of angled parking in the middle of the street

Clematis Avenue, Looking West from the Palms Hotel State Archives of Florida, Florida Memory, http://floridamemory.com/items/show/152572

Clematis Avenue, Looking West from the Palms Hotel
State Archives of Florida, Florida Memory, http://floridamemory.com/items/show/152572

and a recent award winning complete complete street project in Lancaster California with angled parking in the center of the street. The street, shown below, is referred to simply as the Boulevard.

Lancaster Boulevard - After

Lancaster Boulevard – After

The Lancaster Boulevard transformation resulted in hundreds of millions of dollars of private investment along the corridor. (A google street view link of the Boulevard is at the end of the post)

This is what Lancaster Boulevard looked like before the road diet:

Lancaster Boulevard - Before

Lancaster Boulevard – Before

For reference, below is a photo of S. Dixie Highway in the study section. Note the four travel lanes and parallel parking on the east side of the road. In some areas the parallel parking area is replaced by a landcape buffer.

South Dixie Highway - Existing

S. Dixie Highway (Existing) in study area

and here is what S. Dixie could look like in the study section using a mashup of the alternating direction angled parking from the historic Clematis photo and the ramblas of Lancaster Boulevard:


Proposed Dixie Highway center parking

Here is a street mix section (note: existing dimension were estimated from google earth):


Note – It gets even better south of the study area. There is wider right of way that would allow for two lanes with a single row of angled parking in the middle and parallel parking along the sidewalk side like this:

Dixie Hwy. with center angled and outside parallel parking

Dixie Hwy. with center angled and outside parallel parking

In order to have a successful street where people will walk it needs to be comfortable. Two important elements of a comfortable walk are shade and cars that travel less than 30 miles per hour. Drivers take cues from their surroundings to determine the speed they will drive. Cues that slow drivers include on-street parking, pedestrians, cyclists, buildings built to the street, narrow lanes and trees close to the roadway. Pedestrian activity is akin to the classic riddle of which comes first the chicken or the egg. You will not have significant pedestrian activity until you begin to slow cars with the other cues. Once the cars begin to slow then the pedestrians will come and further slow the cars which will then bring more pedestrians.

A few advantages of the street section with parking in the middle of the street compared to a three lane section with parallel parking on both sides are:

  • A three lane section would only provide minimal on-street parking due to number of conflicting driveways on S. Dixie Highway. Providing parking in the middle of the street solves this problem.
  • Placing the trees in the middle, versus on the outside curb side, provides a superior tree canopy that doesn’t interfere with overhead utilities. There will be no need to give trees an ugly haircut to avoid the power lines.
  • Parking in the middle provides edge friction and visually the street appears narrower than the wide open three lane section with parallel parking. Wider streets without edge friction = higher car speeds.
  • The median area can be configured to have pedestrian Ramblas areas as shown here:
Lancaster Boulevard - Ramblas

Lancaster Boulevard – Ramblas

The center median also functions well for community events such as farmers markets and art shows as shown here:

Lancaster Boulevard

Lancaster Boulevard

In summary, providing parking in the middle of the street is the only option that can immediately provide the necessary cues to drivers that they are entering a place and are no longer on a high speed urban arterial. A three lane design with parallel parking will not be effective with the existing driveways and overhead electrical lines.

The middle parking ramblas is not appropriate for all of S. of Dixie Highway. It is recommended that this design be placed in two to three block groups spaced at a 1/2 mile. Two to three blocks make a destination. These blocks would serve as mini villages much like the commercial nodes found at stops along early twentieth century streetcar suburb lines. The mini-villages would be where nearby residents could walk for a cup of coffee, meet friends for dinner, or pick up their dry cleaning. These blocks would be placed equidistant in the north-south direction between the major east-west arterials such as Forest Hill, Southern, and Belvedere. A half mile spacing is suggested since people are typically willing to walk a ¼ of a mile.

An obvious question will be how can a four lane road be turned into a two lane road? First, it is important to understand that a four lane road in an urban area with high amount of access points doesn’t make effective use of all four lanes since the inside lanes serve as de facto left turn lanes. By only providing these two to three block mini villages at half a mile increments it is possible to keep five lanes at large signalized intersections such as Forest Hill, Southern, and Belvedere and have traffic merge down to the mini-villages. A single lane in the mini-village has a capacity similar to two lanes at the large intersections with traffic signals. This is because of the limited amount of time available for all the conflicting traffic movements at the large intersections with traffic signals.

Intuitively the amount of traffic along S. Dixie is not constant. It is reasonable to assume that there is less traffic on S. Dixie as you move away in the north or south directions from the east-west arterials that connect to I-95. By placing the mini-villages halfway between the east-west arterials the amount of traffic passing through the mini-villages is minimized. Drivers whose destination is near the east-west arterials will not experience any delay from the mini-villages. For someone with a longer drive say from Lake Worth to downtown West Palm Beach the additional delay would be a small amount on their overall trip. We also need to consider that the number of trips a road experiences isn’t a zero sum game. Roads experience a phenomenon called induced demand. Induced demand is when the supply of something is increased (like roads) people actually use them even more. A great example of this is the TED talk on Stockholm Sweden’s experience with congestion tolling of roads. The takeaway is that when Stockholm instituted modest congestion tolling at rush hour the traffic dropped by 20%. So 20% of the trips before the tolls really weren’t necessary, but were caused by induced demand from a having a free commodity.

The current four lane road, besides being inefficient at moving cars is also unsafe. This type of  road has a very high crash rate due to rear end crashes that occur when vehicles stop for a left turning vehicle in front of them or sideswipe when changing lanes to go around a left turning vehicle. From a commerce standpoint this type of road is awful as drivers spend their time looking to change lanes around left turning vehicles instead of looking at the businesses along Dixie Highway.

One final point. For many the thought of converting sections of Dixie from a four lane road to two lanes with parking in the middle is far too radical of an idea. There is no way it would work. All the fancy visualizations and well written prose isn’t going to convince them. What should be done is for the City and FDOT to perform a low cost experiment by temporarily installing a few the middle parking mini villages. The Better Block movement has shown how this to provide cost effective temporary installations. Here is a video of a better block project:

Lancaster Boulevard


American Multiway Boulevard examples

The multiway boulevard is an alternative to conventional higher-volume, higher-speed arterial streets. This thoroughfare type may be used where the community’s objective is to accommodate urban mixed use or residential development and a walkable environment on corridors with high traffic demands. A multiway boulevard combines a central thoroughfare for higher-speed through movements bordered by landscaped medians that separate the central thoroughfare from one-way access lanes on each side of the boulevard. The access lanes provide for slower local traffic, parking, bicycle travel and a pedestrian oriented streetside and are designed to discourage through traffic. Multiway boulevards may be considered where a community desires to make a very wide arterial street more pedestrian friendly yet recognizes the need to retain traffic capacity. ( ITE Designing Walkable Urban Thoroughfares Manual)

Multiway Boulevards aren’t that common in the United States. Although recently, they have begun to experience a renaissance. They are much more common in European Cities such as Paris. Below are examples of American multiway boulevards. It is hoped that this list will benefit the planner, engineer, or citizen that is interested in advocating or implementing this type of roadway.

Please feel free to add other multiway boulevard in the comments.

Esplanade Chico, California

This road is unusual in that it was constructed in the 1950s. The design was developed in two hours based on a desire to keep the existing trees. Here is a good article on the history of the Esplanade.

Pendleton Ave. – Lewis-Mc Chord military base (No google street view available, recently constructed)

Palm Beach Lakes Boulevard West Palm Beach Florida. This is unique in that is was constructed after WWII (late 1960s) after multiway boulevards had fallen out of favor and prior to Allan Jacobs work on resurrecting the multiway boulevard.

SE Dixie Highway Hobe Sound Florida. (Service lanes on one side of highway)

K street District of Columbia – There is a photo of this boulevard in the 1957 AASHO Policy on Atertial Highways in Urban Areas (figure E-16).

Octavia Blvd. San Fran. (This project began the multi-way boulevard renaissance. It replaced a double deck freeway spur that was severely damaged in the Loma Prieta earthquake).

El Camino Real Milbrae, CA (Note the very narrow outer median. In order to allow street trees in the outer median the parallel parking is periodically eliminated to allow outer median to widen for street trees. Boulevard on one side).

San Francisco Blvd. Sacramento CA. Suburban street car subdivision. Small multiway boulevard. Center road only has two lanes.

Shattuck Avenue, Berkeley, CA

E Palm Canyon Dr, Cathedral City, CA (This was a retrofit to your typical post war Stroad. A google search will reveal the amazing before and after pictures.)

Pearl Parkway Boulder Colorado (Recent construction)

Southern Parkway, Louisville, KY

Bothell Way, Bothell Washington (Recent construction, currently not shown in google maps)

Lincoln Parkway Buffalo, New York

Ocean Parkway, Brooklyn, NY

Eastern Parkway, Brooklyn, NY

Grand Concourse, NY (An example of what not to do when designing a multi-way boulevard. Vehicle speeds are too high on service lanes. Poor crash history.)

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How to make a great Southern Boulevard Bridge – Part #2

Since our last post the WalkableWPB team has been busy researching the proposed design of the Southern Boulevard Bridge and we have crafted an alternate design that would provide proper bike and pedestrian facilities with a $1.15 million dollar cost savings from the current FDOT proposal, shown in the following rendering:

Southern Boulevard Bridge - FDOT

Southern Boulevard Bridge – FDOT

The current design is very aesthetically pleasing and even pedestrians have been taken into consideration by providing a pergola on the bridge as shown here:

Southern Boulevard Bridge - FDOT

Southern Boulevard Bridge – FDOT

Everything is so perfect that you would want to buy a post card of the future bridge. Unfortunately, if you dig a little deeper you will find that the beauty of the proposed bridge is only skin deep. As we pointed out in our prior post, the proposed Southern Boulevard Bridge fails at providing pedestrian and bicycle facilities worthy of its $90 million price tag. The bridge provides narrow 6′ wide sidewalks (compared to 8′ wide sidewalks on the Royal Park bridge to the north) and a painted white line provides protection to cyclists in the automobile shoulder. It gets even worse on the island, where 5′ wide sidewalks are provided. One a positive note, the latest drawings we received from FDOT now show a 7′ wide buffered bike lane for the island section. However, providing physically buffered bike lanes or widening the 5′ sidewalk to an 8′ wide multimodal path is a much better solution when you have a road pass through a linear park.

The proposed pergolas and overlooks on the bridge make one think that FDOT is really trying to provide first class pedestrian accommodations. However, the proposed narrow sidewalks aren’t in keeping with that vision. It appears that the design has become so focused on aesthetics that everyone forgot who the aesthetics were intended to benefit. All the landscaping, sophisticated bridge design, and Mediterranean Revival architecture doesn’t matter if you don’t create a space where people feel safe walking and biking.

So what could be done differently?

In order to create an environment where people feel safe walking and biking the sidewalks on each side of the bridge need to be widened to a 10′ width. This would allow for a bike lane and sidewalk to be placed behind the protection of a barrier. This configuration would be similar to this proposal:

Approved-for-the-cambridge-street-bridge-over-i-90 www.bostoncyclistsunion-org

Approved-for-the-cambridge-street-bridge-over-i-90 http://www.bostoncyclistsunion.org

Better bicycle and pedestrian facilities can be provided on this bridge for less money; in fact, approximately $1.15 million can be saved from the current design. An explanation follows.

In order to have 10′ wide sidewalks we must find four additional feet on each side of the bridge. Let us start with FDOT’s current bridge proposal. (Note the 6′ wide sidewalk on the right side with two people walking side by side. They must have shrunk the people!)

FDOT Proposal for Southern Boulevard Bridge over the Intercoastal

FDOT Proposal for Southern Boulevard Bridge over the Intercoastal

First, let us look at the automotive shoulder width in our quest to find 4′. At the December 11, 2008 public hearing an 8′ wide shoulder was proposed. Somehow since 2008 the shoulder grew 2′ to a 10′ width. An 8′ shoulder is perfectly adequate to park a broken down car or truck. In fact 8′ is the FDOT standard width for a parallel parking space. FDOT’s current version of its Plan Preparations Manual (PPM) figure 2.0.2 – Bridge Section allows for an 8′ shoulder for “low volume” undivided bridges. So we have found 2′ of the 4′ that we need for each side at no additional cost.

The next place to look is the 12′ wide travel lanes. When choosing lane widths it is helpful to consider context. The project is in an urban area with a traffic signal at the bottom of the bridge on the West Palm Beach side along with a 35 MPH speed limit. FDOT’s one size fits all policy requires a 12′ wide travel lane for an undivided roadway. A 12′ wide travel lane on an undivided highway makes a lot of sense if you have a 55 MPH rural two lane state highway such as SR-710 (Beeline Hwy.) in the northern part of Palm Beach County, but it makes absolutely no sense on an urban bridge with a 35 MPH speed limit. An identical City or County bridge in Florida is allowed to have 11′ wide travel lanes. Cities and Counties in Florida use a less stringent design manual based on national standards. If we go from 12′ to 11′ lanes we now have 3′ of the 4′ required feet.

Now that we have right sized the lane and shoulder widths we will look at the potential cost savings in the type of bridge proposed. The current FDOT renderings depict a post tensioned slab bridge for the main channel bridge. FDOT’s Draft Bridge Development Report (BDR) found that a conventional prestressed concrete I-beam girder was a feasible structure at a cost savings of approximately $2.16 million dollars over the post tensioned slab option. ($134 / sq.ft. prestressed I beam, $171 / sq.ft. post tensioned slab). (957′ long X 61′ wide X $37 sq. ft savings).

With the $2.15 million dollar cost savings we can add the missing one foot of width to each side of the bridge to provide our 10′ wide sidewalk. Using FDOT’s square foot bridge costs it is estimated that adding 2′ of bridge width for 1,080′ of conventional prestressed I-beam bridge ($134/sq.ft.) and 228′ of bascule bridge($1,494/sq.ft.) would cost $971,000. So a 2′ wider conventional prestressed concrete I-beam bridge would actually cost $1.15 million less than the current proposed post tensioned slab design.

In the interest of keeping the post short an analogy would be useful for these two types of bridges. The prestressed concrete I-beam is the Honda Accord of bridges – boring, reasonably priced, and reliable. The post tensioned bridge is the Ferrari of bridges. FDOT’s own bridge development report identified the post tensioned bridge as being higher risk than the prestressed concrete I-beam. The risk is due to the post tensioned slab bridge being a custom design and needing significantly more quality control in construction. Mistakes can happen. The 2007 collapse of the I-35W highway bridge over the Mississippi River in Minneapolis, Minnesota was due to a design flaw.

Perhaps the best question to ask as a taxpayer is what type of bridge would a private toll company, interested in maximizing profit, choose? The answer would be the lower cost, tried and true durable bridge. There is nothing wrong with a signature bridge if you can afford it, but there is something wrong with a signature bridge that provides substandard facilities for the user of the bridge. It is important to get this right. If you are reading this post then you will probably not be alive when the future Southern Boulevard bridge needs to replaced.

Action item: Ask FDOT, Town of Palm Beach, and the City of West Palm Beach to provide wider sidewalks on the both the bride and the island. Go to the Public Meeting this Wednesday, March 11th at the St. Catherine Greek Orthodox church and ask for wider sidewalks.


How to make a great Southern Boulevard Bridge over the intracoastal

In recent weeks the Florida Department of Transportation (FDOT) has issued new policies that makes one think they are finally treating all modes of transportation as equal and understanding that our road rights of way have tremendous place making potential. These policies include buffered bike lanes and making highway beautification a design objective.

So we have a Department that is finally starting to get it, but the Southern Boulevard Bridge is a $90 million project that had its study completed on May 12, 2009 under the old paradigm that created a roadway network with the dubious distinction of having the most bicycle and pedestrian fatalities in the country.

Shown below is the current bridge proposal:

FDOT Proposal for Southern Boulevard Bridge over the Intercoastal

FDOT Proposal for Southern Boulevard Bridge over the Intercoastal

The design is an unimaginative slightly improved replacement of the current bridge. Bicycles get to use the car shoulder and minimum width sidewalks are provided for pedestrians.

The highway section on the causeway is even worse. Unbuffered bike lanes placed right next to the travel lanes and narrow sidewalks

SR-80 Intercoastal Bridge causeway section

SR-80 Intercoastal Bridge causeway section

There have been cyclists fatalities on other intracoastal bridges in Florida with a similar design. The way to build bike facilities to prevent these fatalities is to provide separation of the cyclists from the roadway. This is a relatively new concept in American highway design, but it makes so much sense once you see it. Below is a recent example of where the bike lanes were placed behind the barrier next to the sidewalk.

San Francisco-Oakland Bay Bridge Protected Bike Lanes

San Francisco-Oakland Bay Bridge Protected Bike Lanes

Would you rather ride your bike behind a barrier or next to a car with a white line providing protection?

In addition to being a safety feature these buffers can also be an aesthetic improvement. Below is a rendering of a citizen group’s plan to add buffered bike lanes to the Rickenbacker Causeway in Miami.

Plan Z Rickenback Causeway - http://planzmiami.com/

Plan Z Rickenbacker Causeway – http://planzmiami.com/

In the rendering above it is easy to imagine the causeway becoming a linear park.

We can do better. One only needs to look north to the West Palm Beach side of the Royal Park Bridge for an example of a world class project executed by FDOT and the City of West Palm Beach.


Royal Park Bridge multimodal path along intracoastal

We need to insist on a great Southern Boulevard Bridge. If you don’t insist on a great project then you are going to get the bare minimum in pedestrian and bicycle accommodations. Remember that the new bridge be will around for at least 75 years. Many of us will not be around to see the replacement of that bridge. Right now the current plans are just lines on paper that aren’t set in stone. FDOT has recently decided to spend an additional $12 million on the project to build a temporary bypass bridge. How about spending a little more to have proper bicycle facilities for the next 75 years?

How you can help: Email the FDOT project manager and tell them you want a safer bridge for bicyclists and pedestrians!

FDOT Project Manager:

Vanita Saini, P.E.

FDOT District IV

3400 West Commercial Blvd.

Fort Lauderdale, Florida 33309-3421

Phone:    (954) 777-4468

Toll Free: (866) 336-8435 x4468

E-mail: vanita.saini@dot.state.fl.us

Contact form: http://www.southernblvdbridge.com/contact.html