Intersection Repair
A few weeks ago, we shared a post about Slow Streets, a Vancouver-based planning and urban design group. Today, they're back with an in-depth look at a dangerous intersection in their city. This report is written by Darren Proulx and Samuel Baron.
For decades, a typical North American city’s mobility objectives were simply about ensuring that the personal car could travel unencumbered through our cities and towns. Today, many forward-thinking cities are recognizing the importance of building a more inclusive and safe mobility system. The Vision Zero initiative, with its roots in Sweden, is now becoming standard policy in many North American cities like San Francisco, Portland, Vancouver, New York and Chicago. This inclusive approach to mobility recognizes that it is unacceptable to deem collisions as simply a necessary cost of travel in your city or town.
Acknowledging that traffic engineering has prioritized automobiles for decades, progressive cities like Vancouver are creating plans that place people walking and cycling at the top of the transportation hierarchy of modes. While Vancouver has made significant improvements in its cycling infrastructure, the considerations and infrastructure for people walking are the same as they have been for decades. To demonstrate, simply go to any intersection in your city and observe the relationship between crossing timings and street widths. We suspect that in the vast majority of cases, like Vancouver, your city’s intersection is designed to move vehicles through quickly at the expense of the safety or comfort of people walking. This is despite the knowledge that 75% of collisions with people walking occur at intersections.
Slow Streets’ latest report Intersection Repair: Pender St. & Abbott St. provides empirical evidence of this situation and how it undermines the safety of everyone regardless of how they get around. In December 2014, using publically available crash data, Slow Streets mapped the collision data, finding that higher volumes of collisions were correlated with wider streets. To the Strong Towns network, this should come as no surprise - combining highway geometries with dense urban environments is certainly a recipe for disaster. However, this data only tells us that a street or intersection is dangerous – it doesn’t explain what specifically makes it dangerous for people walking and cycling. To truly determine what's happening at one of Vancouver’s top collision spots, Slow Streets conducted sidewalk observations in August 2015 at the intersection of Pender St. and Abbott St.
The Data
Slow Streets used video footage to capture the activities and directional volumes of all modes entering and leaving the intersection. In total, we observed over 3,500 people walking and cycling and counted 1,454 vehicles. The counts were conducted during weekday middays, weekday peak hours and weekend midday to obtain a snapshot of the intersection’s activity at various times.
On average there are over 4,800 people per hour moving through this intersection. Of that, 75% of people entering the intersection were walking, cycling or using transit. On average there are 187 people cycling per hour, however, Slow Streets observed as many as 286 people cycling per hour through the intersection. These levels of cycling are comparable to the volumes observed by Slow Streets on nearby Union Street, one of Vancouver’s busiest cycling neighbourhood boulevards.
When you break down the mode volumes directionally, it becomes even more clear that people walking account for the vast majority of people moving through the intersection. On average, people walking accounted for 65% of the modal share along Abbott St. (people driving only account for 27%). With a higher transit share, people walking on average account for 33% of people per hour moving along Pender St. The average volumes of people walking North-South along Abbott St. are also 28% higher than the volumes of people driving East-West along Pender St. If there are higher volumes of people walking, why does the intersection design still prioritize the movement of fewer people driving in the opposite direction, at the expense of the safety of people walking?
Dangerous By Design
Standing on a corner and observing people can really help pinpoint how people negotiate city spaces. After analyzing the walking speeds of people, Slow Streets astonishingly found that only 16% of people can safely cross Pender Street in the minimum legal crossing time. We discovered the main reasons for this were the wide crossing distances (17 meters) and short traffic light timing (13 seconds, from when the orange hand starts flashing). This is typical of most streets in North America. Your city’s transportation department likely seeks to maximize vehicular flow through an intersection - wider streets have more roadway capacity and receive a longer light signalization time.
At 5 lanes (4 travel lanes and 1 left hand turning lane), Pender street is 17 meters wide. Due to an automobile focused intersection design, the traffic light timing primarily only accounts for the vehicular traffic volumes on Pender St. Since Abbott Street has significantly less vehicular capacity than Pender Street, it therefore receives a shorter traffic light signalization. This creates a dangerous environment for people walking. People on foot have at most 20 seconds and at least 13 seconds to cross the 17 meter wide Pender Street.
The traffic light signalization design and wide crossing distances for people walking indicates a transportation engineering and city planning preference for maintaining the status quo which prioritizes the movement of vehicles. Simply put, it places people walking to the bottom of the transportation hierarchy. How are we to achieve Vision Zero if our intersection design emphasizes vehicular movement over the movement and security of more vulnerable road users?
From Rhetoric to Reality
While changing the traffic light signalization can help, the central issue is the long crossing distance exposing people walking and cycling to vehicular traffic for protracted lengths of time. Wide streets are dangerous for people walking – one study found that every additional 1 meter of crossing distance results in 3% more collisions. As one cost effective solution, Slow Streets recommends removing the left hand turning lane on Pender Street. The left hand turning lane accounts for 17% of road space, adding 3 meters of crossing distance for people walking. Meanwhile, only one-third of the existing vehicular road capacity is being used on Pender St.’s other lanes. Reallocating the 3-meter left-turning lanes into 1.5 meter floating medians on both sides of Pender Street will increase the number of people who can successfully cross Pender over the minimum legal traffic light timing from 16% to 50%. These changes will not only enhance safety for walking—by reducing the time mixing with vehicular traffic—but will also protect people cycling. Skinnier road right-of-ways also help slow down vehicular traffic, which further reinforces a safer environment for walking and cycling.
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We suspect that this situation is no different than any other major road in cities across North America. Short traffic light timing, combined with long crossing distances, speaks to the bias in transportation engineering and city planning. It places people walking and considerations for their safety and comfort at the bottom of the transportation hierarchy. The movement of vehicles through this intersection is prioritized over people's ability to safely cross the street.
As Strong Town readers know, road diets can result is a safer travel environment for everyone while simultaneously preserving existing road capacity. In North American cities, streets and traffic lights are designed to prioritize the uninterrupted and quick automobile travel. This comes at the expense of everyone’s safety (drivers included!). Many of these streets are over-built and there is plenty of opportunity to re-design these spaces so that they are safer for everyone.
To get to Vision Zero, we need to rethink intersection design in our cities. We must go beyond collision statistics and observe the small minutiae of life in our urban fabric. Designing a more inclusive mobility system starts with understanding the full scope of activities and dangers present on our streets. Those who follow the Strong Towns movement know that to get to Vision Zero, the most critical issue to address is auto-oriented street design through hard measures. We can’t #slowthecars by simply lowering speed limits, this needs to be reinforced with physical designs that force the behavior you want.
Thank you to Slow Streets for sharing this report with our audience. Slow Streets, a Vancouver-based planning and urban design group demonstrates through research that designing streets strictly for automobile right-of-ways is ultimately harmful to cities. Slow Streets calls for slower, more inclusive streets that generate more value and a greater return on investment.