Getting it Right on Iris

The City of Boulder has proposed four options for Iris which are detailed in their storymap.

The City’s Transportation and Mobility department will present this plan to the Boulder City Council on June 27th.  Please write Council in support of alternatives that are safe and can be completed in the near term, OR speak at Council meetings. Letters to the editor are also encouraged. The city will perform further analysis and refine the proposal later this summer, followed by a selection of a preferred option and will be reviewed by Council. Please review Community Cycles analysis and recommendations of alternates A & B below.  Iris for All!

What the city is planning

The City of Boulder Transportation & Mobility Department has prepared options to make Iris Avenue safer and more comfortable for all users. All four options include protected bike lanes. Community Cycles applauds the City for planning this change to Iris Avenue.  

Alternatives A and B would change Iris into a three-lane configuration; two lanes for through-travel and one lane for turning left. A & B would also add protected intersections.  Alternatives C and D would maintain a four-travel lane configuration with no center left-turning lane. Alternatives A and C would put protected, one-way bike lanes on either side of Iris. Alternatives B and D would put a single, two-way protected bike lane on the north side.

The number of lanes at the “bookends”, the intersections at Broadway and at 28th St, will remain unchanged to alleviate traffic backups. The plan would extend the protected bike lanes up to both intersections.

There are substantial differences between the options, with options A and B providing much greater safety for all road users as well as a much reduced timeframe and expense.

Why change is needed

At present, Iris Avenue, a primary east-west route, is dangerous to drivers, not welcoming to pedestrians, and completely unsuited to and unsafe for bicycling. The City notes that average speed on Iris (between Folsom and 19th) is 45 mph, 10 miles an hour over the speed limit of 35 mph, meaning that many drivers are going well in excess of 50 miles per hour on this road. In a collision between an automobile and a pedestrian or cyclist, these are deadly speeds. 

It is not sufficient to assert that cyclists should be expected to use parallel streets like Kalmia and Hawthorn. While these streets may be suitable alternatives for some uses, they include several unsignalized crossings of busy, high-speed streets that would be dangerous for many, including the young, the elderly, and those with disabilities. Moreover, many cyclists will continue to use Iris because it is a more direct route to many destinations, and, therefore, it must be made safer, even if many cyclists prefer alternative routes.

Learn More

Benefits of a 4:3 Conversion

Building bicycle lanes with physical barriers to protect cyclists from fast moving cars is an increasingly standard solution to our unsafe roads. Also becoming standard is reconfiguration of four-lane roads into three-lanes, where there are two travel lanes and one center turning lane. This increases safety by eliminating lane-change-jockying and allowing construction of safer crossings for pedestrians. It also significantly improves access for first responders, who can use the center lane to get around cars.

Learn More

Comparing the Alternatives

Options A and B create more safety for everyone compared to C and D. With their left turn lanes, they also create more convenience for drivers. C and D are much more expensive and slower to implement because utilities must be moved, curb & gutter work, additional concrete,  and additional right-of-way purchased as part of road widening. A and B actually improve routine emergency access because the left turn lane gives first responders a clear path around cars. In contrast, C and D have less room than now because the bike lanes will be separated. In a disaster situation when people want to drive eastward, the two-way bike path of B and D provide a contra-flow lane for emergency vehicles traveling west. 

The City is not ready to present a full-fledged analysis of the pros and cons of each alternative. That will come this summer.  The City did present some basic comparison information in their presentations of the alternatives. Community Cycles built a comparison table based on that information and our knowledge of bicycling infrastructure.

Learn More
Comparision Table

Rebuttal to Arguments

Opponents of change to Iris speak to three primary concerns: Traffic congestion or slower travel, neighborhood cut-through traffic, and emergency access. 

Travel time: We do not yet have complete information on how much travel will slow down if the street goes from four to three lanes. The city’s A and B options do preserve the existing lane configuration at Iris and 28th and Broadway because it is at traffic signals where congestion mostly occurs. Experience in many other cities shows that 4:3 rebalancing has only modest effect when traffic volumes are comparable to those on Iris. Arapaho Avenue from Broadway to Folsom has the same traffic volume as Iris and has a three-lane configuration, yet travel time is generally okay.

Neighborhood cut-through: Neighbors of Iris fear that traffic congestion on Iris will cause some drivers to to leave the corridor and try to accomplish this short journey by cutting through adjacent neighborhood streets such as Kalmia or Hawthorn or Grape. If this happens, the city can install the traffic calming engineering features it has successfully created in many other locations. And if traffic congestion does not increase, few will be motivated to drive these longer, slower streets.

Routine emergency access will actually improve with options A and B  due to the center turning lane.

Disaster evacuation and emergency response will improve in alternatives B and D due to the two-way cyclepath.


Learn More

What you can do

There are two indispensable actions that you should take today: 

  • Write to City Council in support of both options A & B. The easiest way is through their website contact form. You can also send email to the Council. OR, sign up to speak at Council.
    • Please resist the temptation to criticize Option B. Some cyclists oppose two-way cycle paths, but it is critical that we support both options because (1) a failure to do so may mean we end up with the substantially worse options of C or D, and (2) the concerns that one might have about a two-way cycle track (as is proposed in option B) can be successfully mitigated. Those who care about safety (for all users of the roadway) must unite around both options A and B.  

Write a Letter to the Editor of your favorite local news outlet.



Report a Maintenance Problem, City of Boulder

City of Boulder: To report a street maintenance related problem (potholes on the bike path, paths blocked by snow), complete the form and provide your contact information.


Report County Road Service Issue

Boulder County: To report a street maintenance related problem (potholes on the bike path, paths blocked by snow), complete the form and provide your contact information.


Report an Aggressive Driver

If you find yourself in a situation with an aggressive driver, remember you can dial *CSP (*277), free of charge. Report “real time” aggressive driving behavior to the Colorado State Patrol.


Report a Close Call – Inquire Boulder

Have you had a close call with a bicycle, pedestrian or motorist? This data is important and used in analysis of the safety of our streets.


Bike Theft Prevention & Registration

Learn tips and tricks for preventing your bicycle from being stolen, like registering your bike on Bike Index and knowing which lock to use how to properly use it.

Learn More

Join the Advocacy Committee

We aspire to help Boulder become a dynamic and sustainable city that maximizes the safety, comfort, and convenience of its residents and prioritizes long-term environmental stewardship.

Learn More