Idaho passed its law allowing bicyclists to treat stop signs as yield signs and red lights as stop signs in 1982. Since that time many bicycling advocates have attempted to spread this law to other states, and have been met with strong resistance. These efforts continue and the strides that cyclists have made since the early 80s have not lessened the calls for this reform.

More than 30 years after Idaho passed its law, the evidence suggests that it is a safe and effective reform. In 2008, Jason Meggs contacted Idaho’s Office of Highway and Traffic Safety and analyzed statewide yearly summaries of traffic injuries and fatalities, including summaries by county and mode. His analysis found no evidence of a long-term increase in injury or fatality rates as a result of the adoption of the “Idaho stop” law. In 1983, the year after the law was adopted, bicycle injury rates declined by 14.5 percent and there was no change in the number of bicycle fatalities.

While there has not yet been much movement towards broader adoption of the “Idaho stop” there has been some recognition that traffic signals do not always work well for bicycles. This has led to a number of laws, sometimes called “dead red” laws, which allow bicycles and certain other vehicles that are not always sensed by traffic signals to legally proceed through a red light that does not detect them. These laws are more limited, but provide an analogous situation where a rule is modified because the traffic control was not designed for all vehicles.

This post will discuss the “Idaho stop” and “dead red” laws together because they both modify rules for bicyclists when entering an intersection controlled by a traffic control device.

Spotlight State: Idaho

The “Idaho stop” law is really comprised of two rules that modify how bicyclists treat traffic control devices that control intersections. The first rule is the real “Idaho stop” in that it modifies how bicyclists treat stop signs. Although several localities have adopted similar rules, it is singularly unique as a state law.

When bicyclists in Idaho approach a stop sign they:

Slow down, and if required for safety, stop. Yield the right-of-way to any vehicle in the intersection or approaching, if the approaching vehicle will create a hazard while they cross the intersection. Proceed after appropriately slowing and yielding without stopping.

The second rule is a very permissive red light exception. While all other red light exceptions contain language that indicates that proceeding against a red light is only appropriate when the signal fails to detect a bicyclist, the exception in Idaho contains no such language. As with the “Idaho stop” the reason for the law is encouraging cycling by making it easier.

When cyclists in Idaho approach a red light they:

Stop. Yield to all other traffic. Proceed through the red light with caution.

In addition, a bicyclist can proceed through a red light after yielding, without stopping, if making a right turn. Since the law was adopted in 1982 the only change has been a clarification of the red light exception. That change clarified that a cyclist must come to a stop when making a left turn onto a one-way highway, rather than in the same manner as when making a right turn.

What are they?

An “Idaho stop” law allows a bicyclist to treat a stop sign as a yield sign. Therefore, rather than being required to come to a stop, the bicyclist is required to slow down, stop if required for safety, and yield the right of way to any approaching vehicle or pedestrian before proceeding through an intersection controlled by a stop sign. This is an “Idaho stop” because it has been the law in Idaho since 1982, but may more functionally be referred to as a “stop as yield” or “yield-stop” law. Since this is a legal maneuver, it is not to be confused with the practice of motorist rolling stops, known colloquially as the “California stop.”

For an excellent explanation of the “Idaho stop,” watch this video by Spencer Boomhower.

Red light exceptions take several forms and may also be referred to as “dead red” laws. Most of these laws are a reaction to the inability of traffic lights to detect small vehicles, such as motorcycles and bicycles. These laws allow certain vehicles to proceed through a red light after stopping for a specified amount of time. The major features of these laws that vary by state are: 1) the conditions under which a vehicle can proceed through the intersection, 2) the nature of the light that can ignored, and 3) whether there are additional qualifications for the exception.

Why should you care?

The “Idaho stop” gets a lot of strong reactions within the bicycling community. “Dead red” laws get less press. However, both fit together because they are, at least in part, reactions to the difficulties of being a cyclist in a traffic system that was not designed for cyclists. You should care about these laws because they make cycling easier and, based on the available evidence, make it safer. In a world where governments are making great strides to promote cycling as a solution to health and environmental problems, and as a key to economic development, laws that make cycling easier without having a quantifiable downside should be an easy sell.

One problem with the “Idaho stop” is that it undermines an idea that has great mindshare in the cycling community: "Same road, same rules." The “Idaho stop” is clearly a case of "same road, different rules." Earlier this year an opinion piece on the BBC offered that motorists hate cyclists “when they use the roads but don't follow the same rules as cars.” The relationship between motorists and bicyclists is likely not that simple, but the historical commitment of both cyclists and motorists to this idea contributes to making the “Idaho stop” politically perilous for cycling advocates and makes it difficult to discuss the merits of traffic behaviors that cyclists do, but motorists cannot do.

The League supports the development of traffic laws that ensure the fair and consistent treatment of cyclists. We do not currently have a position on “Idaho stop” and “dead red” laws. Our core principles include following the rules of the road including all traffic signs, signals, and markings. “Idaho stop” and “dead red” laws may have many positive benefits and have not been shown to be dangerous, but are currently not widespread. Responsible cyclists should follow the rules of their state and local jurisdictions. Many of the inconveniences of unwarranted stop signs and traffic lights that do not detect bicyclists can be mitigated or solved by engineering solutions, such as the creation of bicycle boulevards and better adjusted signals.

Who has them?

Idaho is the only state that has both a stop as yield rule and a red light exception that allows a cyclist to proceed through a red light after yielding.

Arizona, Illinois, Kansas, Minnesota, Missouri, Tennessee, Utah, and Wisconsin allow bicyclists to proceed through an inoperative and/or malfunctioning light after either a specified period of time or a reasonable period of time.

South Carolina, Virginia, and Wisconsin allow cyclists to proceed through a red light after either a specified period of time or a reasonable period of time.

Tennessee and Wisconsin qualify their laws in unique ways. Tennessee requires that the intersection actually be controlled by a vehicle detection device. Wisconsin requires that the bicyclist have a reasonable belief that the intersection is controlled by a vehicle detection device. Under either law, a cyclist should take extra care to ensure that they can proceed through the intersection and should familiarize themselves with common vehicle detection devices. Utah's law only applies to persons age 16 or older and will sunset in July 2014.

Washington State has a law that requires signals to be adjusted to routinely and reliably detect bicycles. However, there is no law that allows a bicyclist to proceed through a signal that fails to detect a bicycle or otherwise does not change for a specified or reasonable period of time.

Click the chart for the full-size PDF.



Where did they come from?

There is no Uniform Vehicle Code (UVC) provision equivalent to an “Idaho stop” or “Dead red” law. Obedience to traffic lights is generally dealt with in UVC §11-202 and obedience to stop and yield signs is dealt with in UVC §11-403. The authorization of local regulations of bicycles is addressed in the UVC in section 15-102(a)(8). An excellent history of the Idaho law is available here.