Designing for All Ages & Abilities

To make our city safe for travel by walking, bicycling, and other micro-mobility transportation, our streets must be and feel safe for everyone, including those with physical disabilities, age 8 to 80 or beyond. Safety should not depend on the unrealistic assumption that drivers, cyclists, and pedestrians will always behave perfectly. With our current street designs, a simple mistake can quickly lead to tragic consequences.

To achieve safety, we need changes to the design and construction of our streets. This section notes some street engineering solutions that work.

Protected Lanes

In general, where automobile speeds are likely to exceed 20 miles per hour, cyclists and pedestrians need infrastructure that provides physical protection, usually by separating the vulnerable users from the roadway entirely or providing a physical barrier that ensures that cars do not invade road space allocated to other modes.

Protected Intersections

The Dutch have developed a type of intersection that protects cyclists and pedestrians from automobiles in the way described in this video and this one. Boulder now has one such intersection at the junction of Colorado and 30th Street and another partial implementation at Baseline and Mohawk. Variants on this design can accomplish the same underlying goals without compelling cyclists to jog particularly far to the right as they cross the intersection, though these designs use more road space in order to do so. In all variants, the design slows turning speeds and improves sightlines, ensuring that drivers have a real opportunity to spot cyclists in time to avoid a collision, whether they are turning right or left through the space allocated to bikes and pedestrians.

Safe Traffic Signal Operation

The primary danger for cyclists and pedestrians at intersections comes from cars and trucks turning left or right. Several pedestrians have died in Boulder in recent years from exactly this problem. We can drastically reduce the number of these collisions by changing the operations of traffic signals.

One change is called “Pedestrian Head Start”, wherein the pedestrians and cyclists who are crossing in a crosswalk get a head start of three to seven seconds which is shown to reduce pedestrian/vehicle collisions by upto 60%.  This makes them more visible to the turning drivers.

Another change is to not allow left turns when the signal is green, allowing them only on green arrows if the signal head is equipped with a green arrow. This is especially important when left-turning drivers must cross multiple traffic lanes, or when speeds are high. The left-turning drivers must be very attentive to oncoming cars, so they generally cannot pay sufficient attention to the possibility that a cyclist is crossing or someone will be in the crosswalk.

With right turns the problem is similar. A driver making a right turn onto a busy road must watch for cars coming from the left. When they make their right turn, they may not see a person cycling on a multi use path or a pedestrian who is in the crosswalk.

Allowing turns on green-arrow-only means the crosswalks are not occupied by pedestrians and cyclists. This change does reduce the capacity of the intersection to handle a lot of cars. Right now, this trade-off is generally resolved in favor or automobile throughput, at the expense of safety. It is time to truly put safety first in the operation of our traffic signals. These changes do not have to happen at all signals, nor at all times. But they are critically important at many busy intersections.  Cities that have changed all their left turn signals to allow turns on green arrow only observed nearly a 45% reduction in crosswalk collisions.

Eliminate Slip Lanes

Eliminate Slip Lanes – Boulder, like many cities, installed many “slip lanes”, which are curved lanes that make it easier for cars to turn right. Their wide turning radius makes drivers go faster around the turn. Speed around the turn is the purpose of slip lanes, and that means they increase danger to pedestrians and cyclists who are trying to cross either street of an intersection.

Since they are designed to allow faster car turns, slip lanes usually don’t have a stop sign. Drivers often do not yield to pedestrians. Drivers may also que in the bike lane while attempting to access the slip lane. An experienced, careful bicyclist was recently broad-sided on a slip lane at Foothills and Valmont and his serious injuries put him out of work and immobile for two months.

Slip lanes should be eliminated. Boulder has installed many slip lanes that will be expensive to remove and difficult or impossible to meaningfully improve. Nonetheless, the City expects to study ways to make our existing slip lanes less dangerous.

Safe Mid-block Crossings

Nearly 3 in 4 pedestrian fatalities occur at mid-block crossings, often because no crossing facility is provided or because the provided crossing facility is not honored by drivers. In 2018, this amounted to 4,612 deaths in the United States. Perhaps nowhere else in our transportation infrastructure is it more critical to design for all ages and abilities because, especially at unsignalized, mid-block crossings, speed is at issue both for pedestrians (and cyclists) and drivers. For the very young, the elderly, or the disabled, crossing is apt to be relatively slow, making it difficult to discern a gap in traffic long enough to cross safely, especially when crossing more than two lanes of traffic. Reducing the number of lanes that must be crossed and adding a pedestrian refuge in the center makes for a crossing that is much less stressful and much safer. The pedestrian refuge is a safe waiting area in the middle of the crossing, allowing pedestrians to focus on traffic approaching from one direction at a time. Also, when the number of lanes to be crossed at a time is just one, pedestrians can simply wait to cross until a car has stopped in the lane they are crossing. When the number of lanes to be crossed is more than one, any car in the nearest inner lane to be crossed can block the pedestrian’s view of oncoming traffic in the outer lanes further away, especially if that pedestrian is small (such as a child) or in a wheelchair. The threat is particularly severe for children on bicycles because they will likely cross at higher speed and, thus, have less time to react to any cars that have not stopped in the far lane(s). This is among the many reasons that reducing the number of lanes on a street can substantially increase the safety for cyclists and pedestrians

Safe Neighborhood Streets

No one likes cars racing down quiet neighborhood streets. Some people speculate that changing the city’s arterial roads will result in cut-through traffic on residential streets. Boulder and other cities have employed effective strategies to control speed on many neighborhood streets, ranging from speed cushions and speed humps to mini-roundabouts,  chicanes, diverters and more. Which solutions best fits a particular street requires careful analysis by traffic engineers, but you can find many of the typical solutions described here.

Street Design Resources

We like these excellent guides to better street design by the ​​National Association of City Transportation Officials.
A good book on this topic is “Walkable city rules: 101 steps to making better places”. It is available online or at the Boulder Public Library.



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