Let me start by saying I really like road diets (a.k.a. lane diets), because they have at least the potential to reduce motorist’s peak speeds, while maintaining flow.
This was a streetscape and lane diet along a brief stretch of Broadway Road, between Rural and Mill in Tempe (just under 1 mile long). It’s a high bicycle volume corridor, with College Ave intersecting the project area. It was completed in March 2016. There is also a sidepath on the north side that I don’t fully understand / there was and is also an existing frontage road (“Broadway Lane”).
In any event, Broadway is one of Tempe’s (in)famous 3×2 arterial streets, with 3 through lanes eastbound but only two westbound. There are of course more lanes: center turn lanes and so forth, as well as some RTO pockets. The supposed need for the “extra” lane had something to do with the freeway system, or lack thereof decades ago. US60, which runs parallel and 1.5 miles south of Broadway, has since been massively widened. There were traffic volumes stats presented showing volume has decreased over the past many years, as well as a simulation of closing the lane and not having significant adverse effects.
The project road-wise involved a major resurfacing, and then removed the one “extra” (eastbound) through lane and added 2 BLs with that space. Some raised medians were added, and apparently curbs were even moved(?). Anyway, the end resulting BL, and that’s why i mention it here on this page about “shoehorn” BLs, looks pretty tight to me… the asphalt area according to my shoes is a few inches shy of the 4′ “standard” recommended width, while the adjacent lane only appears to be maybe 10′. You can see from the illustratration, above, how a bicyclist fits next to a Ford F-150 (the most popular car in America) in 14′ of space. Any larger vehicle cannot pass a bicyclist legally in the adjacent lane — its driver would be required to change lanes, at least partially, to pass legally.
Undersized Bike Lanes
The BL is substantially under-width; as shown in this pic at the College Ave.
The recommended usable space (usable space excludes gutter) is 4 feet per AASHTO guide.
Riding it feels quite tight. Also, it feels especially tight when next to the very high (15 feet?) sound wall (not visible in this picture, it’s behind from where this pic was taken). The wall is *very* close to the curb (there’s no sidewalk in the walled section, and lends to a nagging feeling of no possible means of escape.
Poking around the City’s project page, this presentation seems to be what got built. It quotes 5′ BLs next to two 11′ general purpose travel lanes, there’s a snazzy perspective diagram extracted from that presentation, at the top of this article. The project was quite expensive in total ($3.857M, for what is less than 1 mile) and I think it moved curbs.
I returned today (3/27) to measure more carefully. It appears the BL is indeed 5′ (from curbface) as shown in the snazzy diagram. The picture above is, indeed, acutely undersized because the gutter pan there flares to a full 2′ near the intersection, leaving only 3′ of usable space. If you are wondering why all this griping about usable space see the example photo at right — this is an under-sized designated BL in city of Tempe. In any event, excluding those oddly-wide gutter pans near College, the gutter pans are the usual ~ 1.5′, leaving 3.5′ of usable space.
When somebody says they’re going to build a Bike Lane — I just imagine they are going to, if nothing else, meet the widths specified in AASHTO, of at least FOUR FEET usable space. It seems to me if the R-O-W available was correct at 27 feet per direction (=5 + 11 + 11 including gutter), it could have been built to 5.5 + 11 + 10.5 (including gutter); this would represent a minimal BL, at 4 feet usable. And realistically, should have been built 6 + 10.5 + 10.5, or even 7 + 10 + 10 (all including gutters). Dedicated space for bicyclists is never required, if you’re going to do it, do it right.
There seems to be ample engineering cover for using narrow — narrower than the designed 11 feet — general purpose travel lanes, see e.g. The Truth about Lane Widths… no loss of capacity, increase (for everybody) safety, slower peak MV speeds. A win-win, yet a lose-lose was chosen.
Anyway, the way it was designed — a 5′ BL (including gutter) next to an 11′ travel lane, here is what typical side-by-side traffic would look like; the driver of anything wider than a sedan, like e.g. the pickup shown, would need to consciously schooch over to the left portion of his lane to provide 3′ of clearance, and anything wider than that, like a heavy truck, or bus, would need to move, at least partially, into the the left lane. [and note when the cyclist is riding through the area where the gutter is a full 2′ wide, in the picture this would mean the cyclist’s tire was just a few inches from the gutter seam]
For another (in?)famous 3×2 and road diet, seeMcClintock Road, just a mile away… That project is most certainly NOT Shoehorned Bike Lanes.
Note that in the potential project discussed at Shoehorn-bike-lanes on Baseline in Phoenix there was no dieting involved; it was just all bad.