More evidence that the Idaho Stop is safer

Someone sent me some links to other studies of the Idaho Stop. Like the oft-cited Meggs study, both seem to indicate that the Idaho Stop law is either safer or, at least, no less safe. 

The Idaho Stop Law and the Severity of Bicycle Crashes: A Comparative Study; Brandon Whyte.

This study found that crashes at stop-light controlled intersections were more severe in Urbana-Illinois than in Boise, Idaho. 

While no significant difference in proportion of crashes exists at intersections verses midblock between the cities, there were differences in the severity of crashes overall. Champaign/Urbana held a 54 percent level of Type B crashes and a 24 percent level of Type C crashes. This compared to Boise’s more balanced 45 percent and 40 percent respectively. 

Type B crashes are more severe than Type C crashes.

It is possible that cyclists in Boise are more accustomed to judging the traffic conditions that are safe for crossing. They may be more likely to use caution when crossing a signalized intersection, while their counterparts in Illinois, who are required to stop and wait at all controlled intersections, are not as skilled at judging a safe traffic crossing, thus resulting in a proportionately higher level of severity and one statistically different than in Boise.

Another plausible explanation for these findings is that drivers are more likely to expect cyclists crossing at controlled intersections when the driver has the right of way. Thus, motorists may in fact be more likely to slow down and avoid a crash or greatly decrease the severity of crash.

Bicyclists’ Stopping Behaviors: An Observational Study of Bicyclists’ Patterns and Practices; Catherine Marie Caverly Silva

This is not a study of the Idaho Stop, per se, but it does have a lot of information about it. In addition it studies non-compliance by cyclists at stop signs in Seattle, noting that this is similar to compliance elsewhere.

Results from this study find that approximately 55% of all bicyclists used rolling stops and/or track stands, 25% failing to stop and only 19% coming to a complete stop. Despite this high degree of non-compliance with the stopping law, no reliable evidence was found exhibiting decreased safety resulting from the use of rolling stops by bicyclists at stop signs.

No accidents or near-incidences were observed during the pilot study, which indicates that this significant non-compliance at two-way stops, two-way yields may not be an exceptionally important issue

Other interesting findings

curbside parking, after crossing an intersection, actually inspires more obedient stopping behaviors for bicyclists

a significant relationship between not turning left and not stopping at the stop sign. These findings are not surprising, as it is logical that left turning bicyclists will stop more often, as they need to yield to more lanes of traffic than do bicyclists turning right or traveling straight.

Descriptively and with a consideration for the limited validity of this qualitative variable, these results support the theoretical assertion that bicyclists are capable of making safe decisions regarding rolling stop.

Update: I'd like to see this second study repeated in Boise. Is compliance in Boise different than in Seattle (and New York City, which this study says is similar)? If compliance is the same, it implies that the law and enforcement does little to nothing to change behavior, so the argument for one law or the other is about optics, politics and the "hardship" of enforcement. If compliance is lower in Boise, then that means we need to do more to study whether or not it is safer. If, counter-intuitively, compliance is higher, then we should still study the safety difference but also need to check our assumptions. In all cases, of course, some confounding variable could be the cause of the difference, but that would be more likely in the latter scenario. 

Comments

[Joe D]

In what way is a "track stand" not a complete stop? I don't have to put my foot on the ground when I stop my car.

[DE]

I didn't read that as meaning that a track stand was necessarily a failure to stop; I just read it as them lumping them all together, which could imply that it's not a complete stop or may just have been done for simplicity so they didn't have to figure each incidence out.

I think a track stand can be either a complete stop or a rolling stop. But I can see how a motorist might not understand that a track stand means the cyclist is stopping, which is why I give them a wave-through when I'm doing one.

[Joe F]

I track stand is most definitely a complete stop.

Likely a person who does not know what a track stand is and assumes it's a very, very slow yield. They just want to make things more difficult for the cyclists.

The same way drivers think that drivers never yield stop themselves. I would LOVE it they actually used red light cameras more. I'm tired of the drivers whining about cyclists and peds when they yield stop as much as cyclists and treat the speed limit as the minimum and not the max speed.

[scoot]

55% of all bicyclists used rolling stops and/or track stands, 25% failing to stop and only 19% coming to a complete stop

I can understand why track stands get lumped in with rolling stops, if the metric used by the observers is whether or not a foot touched the ground. But then what is the difference between "failing to stop" and "rolling stops"? Is "failing to stop" just blowing through an intersection without looking or yielding? Hard to believe that 1 in 4 cyclists is suicidal.

[DE]

A real track stand, done correctly, is definitely a complete stop. I can even go backwards, so how is that not a stop? But you can also do one as part of a rolling stop. I think they just lumped them together for simplicity.

25% suicidal does seem high, but maybe some of these were blow-throughs where there wasn't any traffic and the cyclist could clearly see that. Think empty neighborhoods full of stop signs. No cyclist in the world is even going to think of stopping at those when no one is around. Since they saw no "near-incidents" at all during the pilot study, the blow-throughs really must have been with no traffic around.

[DE]

The PDF of the master's thesis for the second study shows the six locations studied.

(A) Capitol Hill;
(B) Queen Anne;
(C) Greenlake;
(D) Ballard;
(E) the University District; or
(F) Sand Point.

Don't know the city and haven't found any info in the study on traffic levels, but it's 267 pages so maybe I've missed it? She does note gender, helmet use, weather, topography, type of bicycle facility, time of day. She even calculates the influence of observed wind speed on cyclist stopping behavior. Traffic counts missing (or not at least noting the presence of traffic at the intersection) would be odd since traffic would necessarily have an effect of stopping frequency. However, she used volunteers and maybe could only gather so much data.

[Crickey7]

The uniqueness of the Idaho Stop Law, Id. Statute § 49-720, begged the question are citizens less safe by not being required to stop at stop signs and pause at red lights. This study was not intended to answer this important question, but more specifically, to ascertain if any difference in crash severity between Boise (subject to this special legislation) and Champaign/Urbana (subject to the conventional rules of the road) existed in any meaningful manner. . . Findings of significant difference within the study areas showed no real difference in severity with one exception. Property damage
was significantly different within Champaign/
Urbana if the crash occurred midblock versus
intersection.

[Crickey7]

As the designated safety weenie, I hereby declare track stands (and even slowing to a near stop) to be complete stops.

[washcycle]

what is the difference between "failing to stop" and "rolling stops"?

Failing to stop means the cyclist doesn't slow down and behaves as though they have a green light. Rolling stop means they slow down and behave as thought they have a yield sign. Figure 1 on page 18 shows the differences.

[SJE]

Personally, I think we should allow rolling stops for all vehicles. If there is no cross or turning traffic, a complete stop is unneeded, wasteful on traffic flow and gas, and its what 80% of people do anyway.

[ACyclistInThePortCity]

"I hereby declare track stands (and even slowing to a near stop) to be complete stops."

In SF, where legislation has passed the Council (may be vetoed by the Mayor though) to effectively eliminate enforcement against Idaho stops, they have defined such a stop as requiring cyclists to slow to 6MPH or below, as well as yielding.

[Mike]

@SJE: the difference is that a car rolling slowly over someone still causes a lot of harm

[DE]

Too many drivers are already distracted and not really looking where they're going. A complete stop at least allows time for the subconscious to notice things like pedestrians. Allowing drivers to roll through stop signs just reinforces that that it's okay to not really pay attention.

There would be some who would say that if it's okay for one group it should be okay for another, but a driver is protected by a hunk of metal which allows them to be a bit cavalier. Most sane cyclists won't risk blowing through without looking because they don't want to get crushed.

[Smedley Burkhart]

One cannot legislate safe behavior and enforcement of stop signs for motor vehicles, let alone bicycles, is rare enough to be considered arbitrary and capricious. Hence, the law seems relevant only in assigning fault after a collision. To my cynical mind, this relegates the discussion of safety to the far reaches of weenyism.

...but I'm reading. :)

[SJE]

Mike: The point is whether we can have a workable solution. The problem is not whether someone creeps through a stop, its speeding, distraction, fatigue, ignorance and meanness on the road, and lack of enforcement. Enforcing a complete stop is safety theater, a "do something" that avoids the real issues.

[Mike]

@SJE: no, people actually do get hurt/killed when run over by a slowly drifting car

[oboe]

I can see how a motorist might not understand that a track stand means the cyclist is stopping, which is why I give them a wave-through when I'm doing one.

#stealthbrag

[Smedley Burkhart]

Nice one, oboe. One hand to the chest, the other extended in the direction of travel, and a humble inclination of the head, I assume.