Review of motorist slow speed rules

— some vehicles are “slow by nature” (e.g. buses, heavy equipment, or most commonly a heavily loaded truck; especially up a grade, etc). Police seem to have no trouble understanding this is not an impeding violation…
§28-704(A) “A person shall not drive a motor vehicle at such a slow speed as to impede or block the normal and reasonable movement of traffic…”
§28-704(C), A person “driving a vehicle at a speed less than the normal flow of traffic … on a two-lane highway” must give way when more than five others are impeded, but only when safe to do so. [This rarely applies anywhere in a metro area]
§28-721B, “a person driving a vehicle proceeding at less than the normal speed of traffic .. shall drive the vehicle in the right-hand lane then available for traffic or as close as practicable to the right-hand curb or edge of the roadway”. [when driving slowly, must use the right-hand lane on laned roads]
Bicyclists and Far to the Right
Bicyclists are subject to 28-704C, same as motorists — this rarely applies in metro areas; because roads with significant traffic tend to have more than two lanes.
Bicyclists traveling at a reasonable speed (for a bicycle) are not subject to the impeding rule, 28-704A (for two reasons); they are, however subject to being required to ride as far right as practicable 28-815A but only under certain conditions and ONLY WHEN SAFE; This is NOT a safety rule, it is a motorist convenience rule which allows passing of slower bicyclists by faster motorists.
Narrow Lane Exception
Safety advice from experts: when the lane is narrow, to ride near the center of the lane. Where to ride on the road…
When can you “take the lane”, legally? How narrow is narrow? links to cyclingsavvy reference page.
§28-815A is Arizona’s FTR / AFRAP Law, compares ARS to UVC

Since arterial roads throughout the metro region are virtually all narrow-laned, around 10 to 12 feet [see album of typical Tempe arterials w/measurements]; the effect of the exception is that bicyclists cannot be in violation of 28-815A (“FTR”) virtually anywhere on arterial roads. Their position anywhere within the lane is legal, and as mentioned above, a position near the center, or just left of center is safest.
Bicyclists are subject to 28-721B whenever the more-specific rule (FTR / 28-815A) doesn’t apply; typically because of a narrow lane. Bicyclists going slower than the normal speed of traffic (unless turning) must use the right lane (the “slow” lane) while faster traffic uses lanes to the left.

Mandatory Bike Lane use

When bike lanes (designated; not edge lines, shoulders, etc) are provided, bicyclists will tend to use them, even though Arizona has no mandatory use rule, neither for bike lanes, or for shoulders.
Bike lanes, even when provided, often become impassible for a variety of reasons. Commonly: construction and landscape maintenance. When a bike lane is obstructed or otherwise cannot be used, the bicyclist will merge out of the BL into the adjacent travel lane when safe, and continue along using the general purpose travel lane.

First come, first served; motorists wishing to go faster must pass following the usual procedures (in the same lane if the lane is wide, or change into another lane if narrow)
One other common misunderstanding of FTR law
Bicyclists should always Ride With Traffic, because wrong-way riding is very dangerous. It is, however, either extremely unlikely, or impossible to be a 28-815A violation.
Bicyclists traveling in the roadway must, like drivers, use only the right-half of any two way street. If they fail to do so it is a violation of §28-721.
Bicyclists traveling the wrong way on a sidewalk are not in violation of 28-815A, or any other state law (though local laws may apply; only Tempe and Yuma have such laws). Much more about sidewalks here.
Temporary Heading — Extracted from tempe-traffic-collisions
Listing of each Bicyclist Fatality Occurring in Tempe Since 2009
The nine fatal bicyclist crashes (covering years 2009 – 2021; 13 years total ), click on the date for more details:
- 2010-05-10 Right angle at signalized intersection. Cyclist disregarded signal.
- 2010-05-17 Right angle at signalized intersection. Motorist disregarded signal.
- 2013-10-03 Right angle at signalized intersection. Wrong-way sidewalk cyclist collided with right-turning motorist.
- 2014-06-12 Right angle at signalized intersection. Wrong-way sidewalk cyclist collided with turning motorist. [this was coded as Guadalupe, apparently in error(?), anyway it’s included here, click thru the date for full details]
- 2016-02-02 Right angle at signalized intersection (freeway off-ramp). Bicyclist is said to have ignored signal.
- 2017-11-16 Bicyclist in crosswalk struck by motorist turning left; both had “green”.
- 2018-12-06 right-angle at signalized intersection; driver arrested DUI; click thru for latest.
- 2019-01-23 A cyclist was struck from behind while attempting to turn left by a distracted driver.
- 2021-04-02 right-angle at signalized intersection of Mill and Baseline; it involved a turning hit-and-run driver who was arrested for DUI.
Note that, for arcane statistical purposes, ebikes and motorized bicycle are counted as motorcycle, not as bicyclists. In addition to the above a motorized bicyclist was killed 2010-07-10 when a motorist left-crossed the bicyclist at a signalized intersection and fled the scene. And in 2020-05-15 a motorized bicyclist was killed while traveling along sidewalk and crosswalk when he was struck by a motorist who had a stop sign.
In any event, consistent with other urban areas, strike-from-behind tends to be rare. Of the eight total fatalities in twelve years (2009-2020) there has been at most one; the Jan 2019 incident was arguably a strike from behind, but not classic since it involved a bicyclist changing lanes)
Typical arterial narrow-lane
Broadway Rd near Elm, Tempe, AZ westbound.
Typical of multi-lane arterials; Curb lane is 10′ measured from center of lane dividing line to gutter seam. Gutter is 16″. There are also periodic drainage grates that protrude out past the usual gutter seam, the one pictured here is 28″ from curbface; narrowing the usable width in the curb lane to about 9′.