How to make a right turn

These are references to California-specific laws.

In mid December 2016 (SanFrancisco Bike Coaltion) issued a warning regarding how Uber autonomously driving cars make right turns. At nearly the same time Uber has de-camped from CA (see e.g. this 12/22/2016 article from recode), literally loading their fleet onto car carriers and driving them to…. Arizona! The decision was based on CA’s regulatory environment for autonomously-driven cars; Uber decided they didn’t want to pursue special permitting which the CA DMV said was required, whereas Arizona has no special permitting required — so long as there’s a live driver sitting in the driver’s seat. More about Uber, below.

That’s all very interesting, but ultimately just a side-show. How are drivers of vehicles supposed to make a right turn? Below will list both the Arizona rules (ARS), as well as the Uniform Vehicle code (UVC) and since sfbike brought it up, the California laws (CVC) are also included, since they have an interesting additions.

Required position and method of turning

The basic rule is pretty simple:

ARS §28-751. Required position and method of turning
The driver of a vehicle intending to turn shall do so as follows:
1. Right turns. Both the approach for a right turn and a right turn shall be made as close as practicable to the right-hand curb or edge of the roadway.

UVC §11-601 — Required position and method of turning
The driver of a vehicle intending to turn shall do so as follows:
(a) Right turns — Both the approach for a right turn and a right turn shall be made as close as practicable to the right-hand curb or edge of the roadway.

CVC 22100. Except as provided in Section 22100.5 or 22101, the driver of any vehicle intending to turn upon a highway shall do so as follows:
(a) Right Turns. Both the approach for a right-hand turn and a right-hand turn shall be made as close as practicable to the right-hand curb or edge of the roadway except…


We see that ARS and UVC are verbatim copies, and that CA is operatively identical because the added exceptions aren’t relevant… All three contain the identical operative phrase “Both the approach for a right turn and a right turn shall be made as close as practicable to the right-hand curb or edge of the roadway”. The astute reader will notice that the phrasing is identical to the bicyclist FTR (Far to The Right) law, e.g. in Arizona, §28-815A.

Drivers of vehicles violate this law all the time; this is irrespective of the presence or absence of any bicyclists or of the existence of a bicycle lane. It is simply more convenient to not move to the far-right. It is easily one of the most-violated laws. It is considered normative to violate this law, similar to the way not making a complete stop is considered okay.

Whenever there is any excess width in a lane, drivers tend to make the right from the left part of their lane, this allows them to execute the turn faster than they would otherwise be able to. This has safety implications because anyone who might be crossing a driveway or crossing the street will tend to suffer more severe injuries of a collision results, whereas at slower speeds the collision is less severe or can be avoided entirely.

Bike Lanes

Definition per MUTCD: Bicycle Lane—a portion of a roadway that has been designated for preferential or exclusive use by bicyclists by pavement markings and, if used, signs.

What’s wrong with this picture?

When there is not a dedicated right-turn only lane (RTOL), the addition of a designated bike lane complicates matters considerably. (See sidenotes, below; and also see guidance from ITE guide, also below)

The complication stems from placing a lane of through-going traffic, the bike lane, to the right of a lane of traffic which is permitted to turn right. It should be noted that this configuration would NEVER be permitted for two general-purpose lanes of traffic, yet for whatever reason, it’s considered okay to configure bike lanes this way.

So, when a driver is preparing to turn right adjacent to a bicycle lane, what are they supposed to do?

Essentially, the bike lane is constructed between the lane the driver is driving in (the right lane, if there’s more than one available), and the “right-hand curb or edge of the roadway”. However…

ARS §28-815D. A person shall not operate, stop, park or leave standing a vehicle in a path or lane designated as a bicycle path or lane by a state or local authority except in the case of emergency or for crossing the path or lane to gain access to a public or private road or driveway.

UVC (can’t find any explicit prohibition on driving in a bike lane, there are a couple of generic prohibitions)

CVC 21209. (a) No person shall drive a motor vehicle in a bicycle lane established on a roadway pursuant to Section 21207 except as follows:
…(3) To prepare for a turn within a distance of 200 feet from the intersection.

CVC 21717. Whenever it is necessary for the driver of a motor vehicle to cross a bicycle lane that is adjacent to his lane of travel to make a turn, the driver shall drive the motor vehicle into the bicycle lane prior to making the turn and shall make the turn pursuant to Section 22100.


So, in Arizona and just about everywhere a driver of a vehicle adjacent to a bike lane may “cross” the lane in order to reach their destination; they, however, are prohibited from “operating” in the bike lane. All at the same time, they must also somehow comply with the method of turning, which requires the approach and turn be made from as far right as practicable. Kind of vague.

California, on the other hand, is one of a tiny handful of states (MN is another, see 169.19) that offers specific guidance as to how to actually legally accomplish the task. CA being extraordinarily specific, both allowing (an exemption in 21209) and requiring (21717) driving/merging into a bicycle lane by right-turning motorists within 200 feet. The MN law is similar but less specific, no mention of how many feet.

This is all very interesting, but as a practical matter by my observation, the law is widely ignored in CA; as mentioned above the basic rule is ignored by drivers in all states nearly all the time.

Sidenote #1 about Bike Lanes: per MUTCD 9C.04: “Standard: A through bicycle lane shall not be positioned to the right of a right turn only lane or to the left of a left turn only lane.”

Sidenote #2: when a BL is to the left of a RTOL, the right-hook issue becomes irrelevant, because there is no conflict at the intersection — the conflict is simply comes earlier. A potential criss-cross problem arises.

Advice for Bicyclists

The threat of a right-hook collision is a serious safety risk for bicyclists; e.g. in Tuscon there have been three fatalities in the past 3 years involving right hooks, all in bike lanes.

Illustration of a semi-truck right-hooking a car

When riding straight through, bicyclists are at heightened risk for a right-hook conflict anytime there is any excess width, be that a bike lane, or even just a moderately wide travel lane; and don’t forget: this extra risk exists any place a right turn is possible, not just at intersections.

See e.g. Right Hook at Behaviors and Risks for advice on how to mitigate the conflicts.

Fake Bike Lanes

Fake bike lanes are edge lines when used on urban roads. They are generally not warranted per MUTCD and therefore should not be used — however (some) traffic engineers persist; see numerous examples, ADOT, City of Phoenix, City of Tempe and I’m sure many other places.

In any event, they present additional legal difficulties… an edge line is by definition the edge line on the right is by definition the edge of the roadway; irrespective of any curb.

A bicyclist who chooses to ride on a shoulder (in the “fake bike lane”) is not riding in the roadway. Who must yield to whom? An interesting twist to this was codified recently for golf carts driving on the shoulder — the driver of the golf cart is explicitly required to yield to any right-turning traffic(! and see 28-777).

Odd BL Striping

Sometimes the striping can be downright perplexing, and only add to the confusion; as well as add to the possibility of right-hooks.

In this example, installed in early May 2017, the BL stripe formerly just ended ~ 200′ from the intersection, allowing traffic to naturally sort itself out according to destination. This is Central Ave Northbound at I-17, Maricopa Freeway.

Now the BL stripe is extended all the way to the intersection, and follows the (huge)curb radius. Large radii of course allow drivers to speed around the corners without, say, yielding to pedestrians in the crosswalk. [Update: a few days later; so the later part of May 2017, the area was slurry sealed and yet another striping pattern was installed, the BL stripe is still extened to the intersection, but is now straight (doesn’t bend with the curb), and dotted (like a fast dash) ]


What about Uber?

I think autonomously driving vehicles, including Uber, should follow the laws. The law in CA clearly requires that a driver move into a bike lane prior to turning. That being said, I doubt disobeying this CA law by an autonomously driven vehicle is a safety issue — they have sensors that “see” everything, in every direction, at all times, regardless of lighting conditions.

What about Google / Waymo?

So this is pretty straightforward (also see discussion of vidfeo on reddit):

According to the youtube, this is at California St and Rengstorff Ave, Mountain View, CA. As such as noted above is a flagrant violation of CVC 21717 concerning proper position for making a right turn. My recollection was google was aware of this and said they were programming (if that’s the right term) their cars to merge right into a BL when preparing for a right turn; of course I suppose it’s hard to know whether or not the car in the video is operating autonomously(?).

Engineering Guidance

This from the ITE (Institute of Transportation Engineers) Traffic Control Devices Handbook, 2nd Edition:

Bike Lanes and Intersections
As noted in the section on bicycle crashes, most minor vehicle-bicycle crashes on roadways occur at intersections or driveways. Special attention should be given to proper design and channelization of bike lanes at intersections to allow for smooth and consistent traffic flow and to minimize unexpected conflicts.

Bike lanes may complicate both bicycle and motor vehicle turning movements at intersections. Bike lanes encourage bicyclists to keep to the right and other road users to keep to the lef, which may create problems at intersections. Some bicyclists may initiate left turns from the right-side bike lane, placing them in conflict with vehicles proceeding straight through the intersection. Some motorists will begin right turns from the travel lane to the left of the bike lane, placing through bicyclists in conflict with right turning vehicles, contrary to the established rules of the road .. Also, bike lanes can encourage bicyclists to overtake stopped vehicles on the right where drivers will not be expecting overtaking maneuvers. Intersections with free-flow turn lanes or ramps can further complicate intersections where bike lanes are present.
ITE Traffic Control Devices Handbook, 2nd Edition / Chapter 14

On the subject of the how to handle striping at intersections, the ITE Handbook has a diagram of three choices (Fig  14-20: solid to intersection, discontinue / drop near intersection, or dotted near intersection, then they give this noncommittal advice, noting that the MUTCD illustrates (in MUTCD’s fig 9C-6) the dotted option:

Solid, Dotted or Dropped? …There has been quite a bit of discussion in the bicycle transportation community about which of these options is preferable at certain types of intersections, with some practitioners making strong arguments in favor of one or more treatments. Although all three types of markings have been in use for almost four decades, there has never been any formal research study to determine which of them is most effective at a specific type of intersection and at the time of writing of this Handbook, proposals to perform this research have not received funding. Therefore, no detailed guidance can be given at to exactly which marking style is “best,” and engineering judgement should be used to select an option that may be “best” for a specific situation.
ITE Traffic Control Devices Handbook, 2nd Edition / Chapter 14

The MUTCD, as mentioned above by the ITE Handbook, has nothing explict in the body of the Bicycle Lane Markings section 9C-4 saying only that “Standard: Longitudinal pavement markings shall be used to define bicycle lanes.”; but does show the BL stripe becoming dotted 50 – 200′ from the intersection, see Figure 9C-6. Example of Pavement Markings for Bicycle Lanes on a Two-Way Street



Thanks to Dan G for parsing the CA laws.


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3 thoughts on “How to make a right turn”

  1. You are correct that bike lanes complicate intersections. They encourage right-turning motorists to stay left (until time to turn) and cyclists to stay right. Prescott has two roads (Prescott Lakes Pkwy. and Rosser St.) with bike lanes to the right of marked right turn lanes, in violation of MUTCD. These are also at the bottom of steep hills (7% grade) at the intersection with SR 89.

    I’ve told the bike-ped committee about this and I think the city engineer plans to move the bike lanes but he plans to wait until the roads are re-paved. A mitigating factor is the hills are so steep, few people bike there. But it is still no excuse for the road layout.

    There are other places in Prescott with bike lanes on steep hills with the stripes carried into intersections. One of the worst is Willow Creek Road (6% grade). There are no right-turn only lanes so it does not violate MUTCD but it is still dangerous. A cyclist can easily coast at the 40 mph speed limit. The bike lanes are carried right into the intersections, which I call “coffin corners”. I am hoping to get the city to remove the stripes on the downhill side, replacing them with shared-lane markings.

    — Fred

  2. In the always concise words of JF:

    The American (and often elsewhere) traffic system divides turning movements into two parts. The first part is a merge to reach the lane of traffic going in that direction “nearest” the turn: Far right lane for a right turn, far left lane for a left turn. That movement ensures that the turning movement will not cross overtaking traffic that is difficult to see. Only then is the turning movement itself allowed, so that the turning driver has to yield only to the traffic that he can easily see and pay attention to.

    This was from a discussion thread about right-turn comparisons to the “Dutch system”

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