I am a retired architect now living in Marley Park, who for the last 15 years of my career worked on roadway and bridge projects with a civil and structural engineering firm in Tucson and Phoenix, which specialized in bridge design.
I was also a runner, who ran in college, nationally and internationally, and then started riding and racing on the bike; I am now back running. Team New York Life was my last bike racing team.
When the construction started on Bullard Avenue, I was curious as to what they were doing regarding the designated bike lanes, as throughout my career I had never seen anything like it.
My years in bridge design were done primarily in Tucson (although I’ve designed bridges for Goodyear, city of Phoenix, Scottsdale, etc.).
Tucson is a bike-friendly community and on every project we worked hand-in-hand with city of Tucson bike program people, as well as Pima County and local bicycle groups and teams, using all applicable design standards and guides for our roadway and bridge designs, including municipal, county and American Association of State Highway and Transportation Officials standards.
I have never seen or encountered “bike lanes” of the type recently completed on Bullard Avenue. I believe that these lanes are remarkably dangerous for bicyclist and motorist alike for the following reasons:
It appears that the gutter-to-barrier width of the designated bike lane is intended to be 72” wide.
Given a minimum “shy distance” (the distance one instinctively rides away from a curb to the outside of their foot when pedaling), the effective width of the bike lane is only 53”.
I am unaware of any designated bike lane design standard of that width, not to mention that with the shy distance added to the bike centerline to outside of pedal distance, if one were attempt to ride as close to the gutter curb as possible, these dimensions would put their wheels almost directly on the seam between the concrete of the gutter and the asphalt of the bike lane and roadway.
There is no escape from the gutter curb and barrier curb for a bicyclist, so a tree limb, glass or other debris in the bike lane is inescapable – the bicyclist cannot swing wide to avoid the road hazard other than to shoot through one of the barrier curb-cuts out into the roadway.
No typical street sweeper is 72” wide – it is highly likely that the bike lane will never be swept or maintained.
The curb cuts in the barrier curb are for roadway drainage in the event of rain; but rain falling on the roadway will flush the roadway as it drains and the drainage will run along the roadway face of the barrier curb, then drain into the bike lane. In that case, roadway debris may accumulate at each of the curb cut crossings rather than be drained along the entire length of roadway.
The cross slope of the bike lane should be a consistent maximum of 2 percent (2 feet rise over 100 feet of run); given a clear width of 72” from curb to curb, from the bike lane face of the barrier curb at the asphalt ... the riding surface of the bike lane should slope down no more than 1.44”. The cross slope of the bike lane is far in excess of this – not to mention the significant rough drop from the asphalt to the concrete of the gutter.
A broken down vehicle has no where to go except to stay in the roadway – there is no “break down lane” (this is a roadway design term and a secondary function of a typical bike lane). A passenger getting out of a stalled vehicle would necessarily swing their door into the bike lane.
People driving in narrow spaces get nervous and can overreact, especially given the speeds that people non-sensibly drive around here. The roadway travel lane widths are minimal. It is highly likely there will be frequent barrier curb impacts and vehicles mounting the barrier curb, possibly ending up in the bike lane.
Here is a summary of recommendations based on personal experience and professional judgment:
City officials should explain specifically and in detail to which standards the designated bike lanes were designed to; and explain the maintenance, drainage, clear width vs. effective width, and safe and allowable cross-slope employed in their design.
Riders should us great caution while riding in those lanes and never attempt to ride side-by-side; it is not wide enough and someone will definitely dig a pedal and go down – there is simply no room to recover.
Ride right down the middle of the asphalt strip between the face of the barrier curb and the gutter seam (concrete to asphalt seam) to avoid a pedal dig and to avoid a front wheel dig in the rough seam between asphalt and concrete.
Carry extra tubes and air (if you use cartridges to fill); there will be a lot of punctures in these lanes.
What they did on Bullard Avenue is scary and dangerous. Period.
