Engineering Tips To Make City Intersections Safer

U.S. cities continue to experience ongoing growth, and this means that pedestrians and motorists are having to engage with each other frequently. As populations get denser in urban areas, local politicians need to find new and innovative ways to ensure efficient travel for drivers while also maintain safety for pedestrians.

This is no easy task, and intersections the areas where interactions between pedestrians and drivers become most dangerous. While pedestrians have the right of way in crosswalks, physics and mass give cars an advantage if they strike pedestrians.

Cities are starting to use technology and other strategies across their public roads. This is an effort to combat the trend of increasing deaths from traffic accidents in the United States.

Address The Need For Safer Intersections

Most municipalities are willing to invest in new technology across their transportation systems to help improve efficiency and reduce carbon emissions. Cities often invest in conventional traffic safety equipment like traffic cones to assist roadway construction, but many situations require more advanced solutions to address inefficiencies and dangerous intersections.

These improvements not only improve public roads, many cities are starting to turn their city into a “smart city” with advanced technologies communicating across a complex network of systems.

Since these systems are expensive and concerns about security and other issues prevent these systems from being fully implemented, many cities are not able to implement the advanced tech necessary.

This means that only the wealthiest cities are capable of taking a technological approach, but even cities who struggle to balance their budget can build safer public streets with some simple, yet effective intersection designs.

Designing or updating our city intersections is one of the most important aspects of roadways safety because any improvements will have an immediate impact on citizens. Drivers will be able to commute safely with reduced collisions, and pedestrians will be able to cross busy roads with less risk of injury or death.

 

Types of Intersection Innovations to Protect Pedestrians

At the most basic level, making intersections safer for pedestrians and motorists comes from making the environment more controlled.

One of the most significant variables that lead to injuries and deaths is when either pedestrians or drivers act in unexpected ways, so finding ways to alter traffic flow when pedestrians are present or maintaining consistency at intersections is key to reduce injuries and deaths

Here are a few ways that engineers and local policymakers can work together to ensure smooth transportation for drivers while also making intersections safer for pedestrians. 

Connected Traffic Safety Lights

One of the most practical ways to make intersections more predictable is to install street traffic lights. While these lights can be conventional safety lights, there are several models that allow traffic control officials to install sensors on lights to change timing and improve the security of the area.

These lights will sense when pedestrians are present, and their timing will change based on the time of day and traffic density. This will result in improved throughput of traffic, while also taking into consideration the needs of pedestrians at specific times and on specific days.

Connected signals are smart enough that it knows when to offer a way for cyclists and mass transportation. Aside from that, they could help the emergency workers get to the destination faster by providing them green lights.

Pedestrian Head Starts

One of the simple, yet effective adjustments that can be made to modern intersections is to allow an interval of pedestrian walk time before the signal changes. This type of timing adjustment will provide a buffer between the time that pedestrians cross the road and turn signals for cars to take left or right turns.

pedestrian safety city intersection pedestrian head start
Source: https://www.sfmta.com/blog/giving-pedestrians-head-start

This gives the walkers an idea when to move, and it also reduces the conflicts between pedestrians and turning vehicles. As a result, this type of signal change will improve the visibility of crossing pedestrians by reducing the amount of time overlapping for cars and pedestrians crossing the same area of city roads. “No Turn on Red” signs are also suggested, and it should go with the modified signal timing to create a brief walkers-only zone in the crosswalk.

Protected Left Turns

Left turns are considered to be the leading cause of traffic accidents, and it even outnumbers right turn crashes in heavily congested city streets. OTREC studies have shown that that left turning drivers are more distracted because they have to worry about oncoming traffic, and since their attention is on their own safety many drivers fail to ensure the safety of pedestrians.

intersection safety pedestrian protected left turn city intersection safety
Source: https://www.fhwa.dot.gov/publications/research/safety/04091/04.cfm

When motorists don’t have protected left turns, which are often marked by a green arrow. This holds true to the standard, green-light free-for-all as well, which creates a dangerous mix.

Fortunately, this can quickly be resolved without the need to spend a lot. That small green arrow could save lives because left-turners are a potential time-saver, and that’s why it’s a common practice in most cities. Aside from that, according to David Hurwitz, a lead researcher of OSU, there will be situations where it’s ideal that the goal of safety would override the goal of efficiency.

Raised Crossings and Intersections

Raised crossings and intersections are like speed-bump platforms that ramp up crosswalks, and it can also be utilized on intersections. This traffic calming technique introduces a physical barrier to prevent motorists from injuring or killing pedestrians.

raised intersection pedestrian safety city intersection engineering tips
Source: https://safety.fhwa.dot.gov/intersection/other_topics/fhwasa06016/chap_6.htm

Raised crossings are speed table for the entire intersection, and it works in two ways– it improves the perspective of motorists as it makes them taller, and slows down the vehicle. In Phoenix, Arizona, one of the intersections there are called “bollards,” and they are placed on the sidewalks and leveled with the raised-up streets.

Protected Intersections

These are specifically designed to protect bike lanes from the intersection. Alta Planning + Design’s Nick Falbo came up with blueprints that are prioritizing bikers and walkers within the vicinity.

protected intersections city intersection pedestrian safety intersection technology
Source: https://momentummag.com/protected-intersections-latest-trend-cycling-safety/

One essential design element of this is the “corner refuge island,” that’s similar to a neckdown, but with a bike lane running through the center.

This encourages the motorist to turn a full 90 degrees before hitting the crosswalk whenever they do a right turn, as it makes the intersection overall, shrinking the distance pedestrians have to traverse.

Neckdowns

Neckdowns contract the amount of street space pedestrians have to cross as they extend the curb into the intersection.

pedestrian safety city intersections neckdown intersection safety technology
Source: http://opendurham.org/news/quick-updates-duke-gregson-east-end-connector

Through this, the safety of slower pedestrians are guaranteed– this includes the elderly and small children. Also, because the curbs are often built in large bulb shape, they are also capable of slow turning drivers down.

The Barnes Dance

Last, but not least, is the Barnes Dance– this was named after Henry Barnes, a traffic engineer because he created a system where it restricts right turns on red and turns the whole intersect into a walker’s only zone.

the barnes dance intersection safety pedestrian city intersection technology
Source: https://www.bedloo.com/bedloos/do-you-like-the-barnes-dance-style-diagonal-crosswalk

Crosswalks are often placed in the shape of an X through the center, with four corners for the walkers to cross diagonally. This allows pedestrians to cross from one corner to the opposite end without having to wait for two lights. Not only does this engineering method make crossing intersections more convenient for pedestrians, it also reduces their exposure to oncoming traffic. 

Making Intersections Safer For All Cities

City planners and policy makers will need to work together as more drivers take to public roads and interact with pedestrians at intersections. While driver distraction and other variables lead to increased injuries and deaths on the road, the above engineering tips cities can improve the safety of their intersections with limited resources. The future of city development looks bright as more city planners implement these modern traffic calming techniques on busy intersections!

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Author: Chris Giarratana

Chris is a Digital Media Strategy and PPC management consultant in Orlando, FL. He develops marketing strategies for small businesses, researches emerging technologies, and enjoys studying transportation issues.

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